How do I fix this java.lang.NullPointerException: null on my code?

My teacher asked us to create a class named Pizza that stores information about a single pizza, which should contain:   Private instance variables that store the size of the pizza (small, medium, or large), the number of cheese, pepperoni and ham toppings. Constructor(s) that set all of the instance variables. Public methods to get and set the instance variables. A public method name calcCost() that returns a double that is the cost of the pizza.   Pizza cost is determined by size. Small = $10 + $2 per topping. Medium = $12 + $2 per topping. Large = $14 + $2 per topping.   A public method named getDescription() that returns a String containing the pizza size, quantity of each cost and the pizza cost as calculated by calcCost().   Here is my class:  public class Pizza {      private String pizzaSize;      private int numOfCheese;      private int numOfPepperoni;      private int numOfHam;  public Pizza (String a, int b, int c, int d) {     a = pizzaSize;     b = numOfCheese;     c = numOfPepperoni;     d = numOfHam; }  public String getSize() {return pizzaSize;}  public int getCheese() {return numOfCheese;}  public int getPepperoni() {return numOfPepperoni;}  public int getHam() {return numOfHam;}  public String getDescription() {     return ("Size: " + pizzaSize + "," + "\t" + "Cheese Toppings: " + numOfCheese +          "\t" + "Pepperoni Toppings: " + numOfPepperoni + "\t" + "Ham Toppings: " +          numOfHam + "\t"); }  public double calcCost() {     double cost = 0.0;     int numOfToppings;     int costOfToppings;     if (pizzaSize.equals("Small"))     {cost = 10.0;}     else if (pizzaSize.equals("Medium"))     {cost = 12.0;}     else if (pizzaSize.equals("Large"))     {cost = 14.0;}      numOfToppings = ( (numOfCheese + numOfPepperoni) + numOfHam);     costOfToppings = (numOfToppings * 2);     cost += numOfToppings;     return cost;     } }   Here is the demo driver that goes with it:      public class Question11 {     public static void main(String[] args)     {         // Create a few sample pizzas and output their prices         Pizza supreme = new Pizza ("Large",1,2,1);         Pizza cheese = new Pizza ("Medium",2,0,0);         Pizza pepperoni = new Pizza ("Small",0,0,2);         System.out.printf( "%-75sCost: $%5.2f %n",     supreme.getDescription(), supreme.calcCost() );         System.out.printf( "%-75sCost: $%5.2f %n", cheese.getDescription(), cheese.calcCost() );         System.out.printf( "%-75sCost: $%5.2f %n", pepperoni.getDescription(), pepperoni.calcCost() );     }  } // Question 11   The java.lang.NullPointerException: null error comes up on the size.equals part and the supreme.calcCost() for the driver. Any help is appreciated, and yes I read the other java.lang.NullPointerException forums/questions on this site and I am still confused.


In Javascript what is the difference between:  var name = function() { //stuff to do };  {name : function() { //stuff to do } };  function name() { //stuff to do };


fantasy- looking for a zombie/supernatural book

The book has a college-age girl gets hired at a supernatural bookstore as a editor for a city guide, and involves zombies and other creatures. It also involves citywalkers who hear the personality/voice of the city itself.


MStest throwing errors for Class library using multiple config files

I have created a class library MultipleConfigFiles, which has a method getConfigData. This method reads data from config files.      public class Class1     {       public string getConfigData()       {         string configData = ConfigurationManager.AppSettings["key"].ToString();         return configData;       }     }   Now I have a console application ConsoleAppConfig, in which I have given the reference of the class library.In the main method, I have created a object for the library class and called the method.  static void Main(string[] args)         {             Class1 c = new Class1();             string data = c.getConfigData();             Console.Write(data);             }   This console application has 2 different config files dev.config and prod.config. In the main App.config file , I have used configSource to map the appropriate config file.  <appSettings configSource="dev.config" />   Dev.config file looks like this:  <?xml version="1.0" encoding="utf-8" ?> <appSettings>     <add key="key" value="dev" /> </appSettings>   Till here it is working fine.That is, when I run the console app, the method returns dev.  Now,I have created a MSTest project for this class library.  public class Class1Tests     {         [TestMethod()]         public void getConfigDataTest()         {             Class1 obj = new Class1();             var result = obj.getConfigData();                         }     }   Now the problem is, when I run this test, it throws an error saying "An exception of type 'System.NullReferenceException' occurred in MultipleConfigFiles.dll but was not handled in user code. Additional information: Object reference not set to an instance of an object."  Since the config files are in ConsoleApplication , the method is not able to read the appsetting variables from there. Is there any way I can maintain the configuration files globally so that both of them use individually , or is there any better way to handle this.    Any inputs are appreciated.Thanks.


Mavericks Internet Sharing over Ethernet stopped working

I'm on 10.9, and I had been using internet sharing successfully again for the first time since Lion. Today though, it just decided to stop working again.  Network layout:  Modem -ethernet-> Router -ethernet-> Mac Pro -ethernet-> MacBook Pro Retina   The internet works fine on the Mac Pro, but it is no longer forwarding the proper DHCP settings to the MacBook.  Previously, the MacBook would get the IP address of 192.168.2.12, and was able to surf the web fine. (Though it wasn't able to connect to any AirPlay/AirPrint devices while on the ethernet interface)  Sometime today, a setting got messed up, and I'm not sure how to fix it or what setting it is.  The MacBook now has a "Self-assigned" IP of 169.254.121.24, even though it is set to use DHCP. The ethernet port on the Mac Pro that the MacBook Pro is connected to is showing a "Self-assigned" IP of 169.254.36.53, even though it is set up to use DHCP as well.  The internet sharing options appear to be correct: share connection from Ethernet 1 to Ethernet 2.  But alas, for no apparent reason, I'm not getting internet access.


Is it possible to get the output of only sudo command?

I want to write the output of only sudo command to some file i.e. the line which I get on terminal after writing sudo i.e.   [sudo] password for user:   If I use sudo ls > file or sudo ls 2> file then I get the stdout and stderr respectively of the whole command. Also I can't use sudo > file or sudo 2> file, then I will get error that I should use some options or command after sudo. So, is it possible to achieve?


Prove that 41^n-14^n is a multiple of 27 I tried to factorise 41^n-14^n but 41 is a prime.  How should I go about


I use SQL Server 2008 R2 and want to set value for fill factor property in each index. I look for recipe to calculate best value for this property (have better performance when insert record) . Also how I can meter query performance by set deference value to this property.  Thanks a lot in advance.


Let $G,H,K$ be three groups. If $G\times H$ is isomorphic to $G\times K$, then is it true for $H\cong K$?


Prove that convex set has empty interior if and only of there exists a hyperplane containing the set.

I was reading about the convex set and its various properties. I came up with a theorem but don't know how to prove it.  Theorem: A convex set has empty interior if and only if there is a hyperplane containing the set.  Someone please give an idea how to prove it.


I have read both but not sure which means what?     There are many such products available on the market.    There are many such products available in the market.    Note: I'm pretty clear about using on while describing the product availability on the Internet where in does not sound okay to me.


i want find the answer and method of solve of $\int\frac{1}{1+x^4}dx$.  I know $$\int\frac{1}{a^2+x^2}dx=\frac{1}{a}\arctan\frac{x}{a}+C$$,  How I can use this to solve of that integration.


I want to start a guide for explaining the theory behind industrial robot arms, like this one:    I want to create some command for drawing a 3D schema of the robot arm. My commands should:   Store in a variable the robot parameters (like number of arms and their length); Store in a variable the kinematic state (angles of joints); Have a command for drawing the arm using the previous two variables as argument. Draw some data in the figure, like a formula near a joint.   At the end I'd like to have commands for easily drawing something like that:    I don't want that you creates these commands for me, it should be my effort and I have to try something by myself at first, of course...  Instead I'd like to know which packages I have to study in order to create a custom package with commands that I need. I know a bit TikZ, but  that's not very well suited for this kind of work. I've read about Asymptote, that I know but I've never used, as well as .  Do you suggest one of these two, or you have some other package in mind that it's more suited for my needs?  EDIT:  I don't think that's a duplicate question, because it's not regarded on how draw something general. My question is very specific on about drawing a schema of a 3D robot by creating a specific command, so the package must be able to draw 3d shapes and it should be possible to do it in a parametric way.


LaTeX symbols like \diamond, \circ and \square when compiled are in the form of symbols that are transparent. How can I fill black color into these shapes? For example, \circ shaded black is \bullet. Is there any command similar for \diamond and \square?


Restoration of system image causes STOP 0x07B BSOD

I restored a Windows 7 Clonezilla image of a Dell laptop I had to a virtualbox hard drive. During the boot process, I get a BSOD,  I've tried repairs using both the internal system repair and using a Windows installation CD. I've run chkdsk and bootrec as well with no success. Booting in safe-mode hangs at classpnp.sys. Any ideas how to fix this?


md5 Hash for 12.04.3 versions not listed

The UnbuntuHash page only lists hashes up to version 12.04.2.  Where can I find the hash for 12.04.3?


Recovery of deleted folders in home folder

By accident I've removed some folders (they were empty) in my home folder. I've created a new ones but they doesn't have proper icons etc... how can I recreate them step by step?


Let $(x,y)\in \mathbb{R^2}$ and consider the series   $$\lim_{n\rightarrow \infty}\sum_{\ell,\,k=0}^n \frac{k^2 x^k y^\ell}{\ell!}$$  Then for what values $(x,y)$ the series converges. I have absolutely no idea how to deal with it.


I wish to upgrade my current Ubuntu 13.04 to 13.10. While upgrading via software updater, it popped up a window with information that "Ubuntu 13.10 is beta".   So, may I know when it would be beta-free? As it's beta, so can it be reckoned stable or once it's free of beta then only it's stable? Is it preferred or advantageous to not upgrade my system now and put off until it's beta-free?


Consolidate photos and eliminate duplicates?

I have a client who is having a lot of trouble managing his photos.  He has multiple copies in multiple Aperture and iPhoto libraries, imports from old PCs, etc.  What I'm looking for is a piece of software for OS X that can grab all these photos and reorganize them by EXIF data, say into YYYY/YYYY-MM-DD/*.jpg, eliminating duplicates as it goes.  Does such a thing exist?


I hereby propose that the tag  be burninated. The tag's wiki:   is for questions about the entire network of Q&A sites that make up the Stack Exchange network.  is circular to the site definition:  Ask questions about issues that affect all Stack Exchange sites   Theoretically speaking, all questions on the site should use this tag! However, only 1,281 questions do. I think this tag is pointless and circular. Please burninate.


Assessing the performance of a neural network in classification task that involves more than two class types

In terms of evaluating how well a neural network performs in a classification task with the number of classes greater than 2 (for example, classifying an observation into one of the 4 classes), which would be a better measure to use: (i) error-based measures such as the cross entropy loss, or (ii) strict accuracy rate? And what would be the advantage(s) of one measure over the other? The previous posts on this topic only discusses about the case of binary classification. Thank you.


How to display a number as output value in node-editor?

I would like to input a numeric value and output also a numeric value after it has gone through some nodes realizing a mathematical function.   I know how to realize the mathematical function with multiply and adding nodes (here: f(x)=x^2 + 5x ) but I do not know how to continue from the ADD-node on to display the output as a number.


Why can't I paste § into a Minecraft command?

According to , using §1 in an item's name should make the text colored dark blue.  However, when I copy-paste a command like this one into chat:  /give @p diamond_sword{display:{Name:"{\"text\":\"§1Sword\"}"}}   it comes out like this:  /give @p diamond_sword{display:{Name:"{\"text\":\"1Sword\"}"}}   See the problem? I can't copy § into chat!  Which means the name ends up being "1Sword" rather than "Sword" colored dark blue.  Why can't I copy § into chat? What can I do to fix it?  Note: I've tested this issue on Minecraft versions 1.14.3 and 1.12.2. It worked the same on both. Feel free to leave a comment if you need more details.


If $S_n$ has cyclic subgroups of these orders or not?

This question was asked in my quiz and I am having difficulties in solving it .  Question : For a positive integer $n$ , let $S_n$ denote permutation group on $n$ symbols. Choose correct statements from below. (a) For a positive integer $n$ and for every $m$ with $1\leq m \leq n , S_n $ has a cyclic subgroup of order $m$; (b) For every positive integer $n$ and for every $m$ with $n<m <n!$, $S_n$ has a cyclic subgroup of order $m$; (c) There exists positive integers $n$ and $m$ with $n<m<n!$ such that $S_n$ has a cyclic subgroup of order $m$; (d) For every positive integer $n$ and for every group $G$ of order $n$, $G$ is isomorphic to a subgroup of order $S_n$ .  Attempt: (a) is true as I can choose an element of length $m$ which will generate cyclic subgroup of order $m$. (b) Choose $n=4$ and $m=19$ to contradict (b). (c) I dont know if there can be found any such case and if yes how to do so . (d) I dont know about it . kindly tell. Answer:   A,C,D are true


How do I protect my website from sql injections?

I have a basic website in PHP that is a search engine and run's off a mysql database but I need to protect it from sql injections can someone explain to me how I can do this?  My PHP script:    <meta http-equiv="Content-Type" content="text/html; charset=utf-8" /> <title>Search Engine - Search</title>
Search Engine
 <form action='./search.php' method='get'> <input type='text' name='k' size='50' value='<?php echo $_GET['k']; ?>' /> <input type='submit' value='Search'> </form>
 <?php $k = $_GET['k'];  $terms = explode (" ", $k); $query = "SELECT * FROM search WHERE ";  foreach ($terms as $each) { $i++;  if ($i == 1) $query .= "keywords LIKE '%$each%' "; else $query .= "OR keywords LIKE '%$each%' "; }  // connect mysql_connect("*******", "******", "*******"); mysql_select_db(*******);  $query = mysql_query("$query"); $numrows = mysql_num_rows($query); if ($numrows > 0) {  while ($row = mysql_fetch_assoc($query)) { $id = $row['id']; $title = $row['title']; $description = $row['description']; $keywords = $row['keywords']; $link = $row['link'];  echo "
$title
 $description

"; }  } else echo "No results found for \"$k\"";  // disconnect mysql_close();   ?>


how to center bigger div under smaller div

I have a login page that is absolutely centered in the middle of the page both horizontally and vertically.  Inside there are 2 divs, smaller pink one and bigger blue one.  How can I center the bigger one?    .container {     background: rgba(249, 249, 249, 1);     bottom: 0;     box-shadow: 0 4px 8px 0 rgba(0, 0, 0, 1), 0 0px 4px 0 rgba(0, 0, 0, 1);     height: 342px;     height: max-content;     left: 0;     margin: auto;     padding: 60px 30px 60px 30px;     position: absolute;     right: 0;     top: 0;     width: 300px;     overflow: visible;  } .smaller {     background: pink; } button {     background: linear-gradient(rgba(239, 83, 80, 1), rgba(179, 47, 47, 1));     border: 0;     color: rgba(255, 255, 255, 1);     margin: 10px;     padding: 8px 70px 8px 20px;     box-sizing: content-box;     width: 50px; } .bigger {     width: 400px;     text-align: center;     background: blue }

Sign In
     <input>

     <button>Back</button><button>Login</button>


Can Phantasmal Force Incapacitate Someone?

The spell Phantasmal Force allows the caster to implant an illusion into a creature's mind. Would it be possible to use some form of illusion that would make the target believe it is incapacitated, so therefore it would be incapacitated?


please help me to remove the "Abstract title" without removing the content of the abstract.  \documentclass[5p]{elsarticle}  \usepackage{xpatch} \xpatchcmd{\MaketitleBox}{\hrule}{}{}{}% remove first horizontal rule (above abstract) \xpatchcmd{\MaketitleBox}{\hrule}{}{}{}% remoce second horizonral rule (below keywords)  \usepackage{lineno,hyperref} \modulolinenumbers[5]  \journal{Journal of \LaTeX\ Templates}   \begin{document}  \begin{frontmatter}  \title{test title}  \author{ Hariha\corref{cor1}*}   \address{820081,Fukuoka, Japan} %\fntext[myfootnote]{Since 1880.} \cortext[mycorrespondingauthor]{Corresponding author} \ead{me@lab.jp}  \begin{abstract} This template helps you to create a properly formatted \LaTeX\ manuscript. \end{abstract}  \begin{keyword} MEMS %\texttt{elsarticle.cls}\sep \LaTeX\sep Elsevier \sep template %\MSC[2010] 00-01\sep  99-00 \end{keyword}  \end{frontmatter}  %\linenumbers \section{The Elsevier article class}  \paragraph{Installation} If the document class \emph{elsarticle} is not available on your computer, you can download and install the system package \emph{texlive-publishers} (Linux) or install the \LaTeX\ package \emph{elsarticle} using the package manager of your \TeX\ installation, which is typically \TeX\ Live or Mik\TeX.  \end{document}


I have three classes inherited from same parent class. and i have function that takes parent type(typical polymorphism) as parameter. How do i distinguish the true type of the object? Thanks  class Parent{} class A : public Parent{} class B : public Parent{} class C : public Parent{}  void test(Parent &input){ /*      how do i know the object is A, B or C?      I want to perform some operations on the input      but it's different depends on input's true type. */ }


Queries to find duplicate rows in a database and  to delete them.   Can anyone explain these queries how they are fetching the result ?  SELECT       *  FROM       emp a  WHERE       rowid = (SELECT MAX(rowid)                FROM EMP b                WHERE a.empno=b.empno)     to Delete:   DELETE FROM       emp a  WHERE       rowid != (SELECT MAX(rowid)                 FROM emp b                 WHERE a.empno=b.empno)


I want to offset the edges. An reference.gif is attached. I have done in other software. Can we offset the edges in that way.


In a faraway country, they have a strange culture where they favor girls over boys. Additionally, they know that boys are trouble, so they settle for one in a family. Thus, each family give birth until their first son is born, and then they stop (they never take the risk of having two boys – double trouble ...). As a result, families in this country are of the following types:  a. Boy  b. Girl, Boy  c. Girl, Girl, Boy  d. Girl, Girl, Girl, Boy  e. … Are there more girls or more boys in this country? You may assume that 𝑃𝑟(𝑏𝑜𝑦)=𝑃𝑟(𝑔𝑖𝑟𝑙)=0.5  Is the answer is that it is equal number of boys and girls because the Expected Value is 2, what means that for every boy there will be born a girl ?


I had Windows 8 installed on my system, which I screwed up, and now I run Ubuntu 12.04. While installing, Ubuntu used all the 461 GB of HDD space (one partition).   Now I want to make a new partition of maybe 100 GB or so, in order to install Windows 7 alongside Ubuntu (with a dual-boot). But I can't even get a partition done. I can't change the partition in GParted either - the option is disabled.


CloseableHttpClient httpclient = HttpClients.createDefault(); HttpGet httpget = new HttpGet("http://localhost/json");  ResponseHandler<MyJsonObject> rh = new ResponseHandler<MyJsonObject>() {      @Override     public JsonObject handleResponse(             final HttpResponse response) throws IOException {         StatusLine statusLine = response.getStatusLine();         HttpEntity entity = response.getEntity();         if (statusLine.getStatusCode() >= 300) {             throw new HttpResponseException(                     statusLine.getStatusCode(),                     statusLine.getReasonPhrase());         }         if (entity == null) {             throw new ClientProtocolException("Response contains no content");         }         Gson gson = new GsonBuilder().create();         ContentType contentType = ContentType.getOrDefault(entity);         Charset charset = contentType.getCharset();         Reader reader = new InputStreamReader(entity.getContent(), charset);         return gson.fromJson(reader, MyJsonObject.class);     } }; MyJsonObject myjson = client.execute(httpget, rh);   Apache gives the above example, but I've never seen that syntax. It looks like the definition of ResponseHandler() is being assigned to a variable; no idea what this means. Is all this code in a single method of a class?


Store password as hash in wpa_supplicant.conf?

This question is very much related .  I want to log into a user and password protected wifi which uses PEAP and maybe MS-CHAPv2. My wpa_supplicant.conf has to contain an entry like this:  network={     ssid="<somessid>"     key_mgmt=WPA-EAP     eap=PEAP     identity="<someidentity>"     password="<somepassword>" }   Now, I do not want to get displayed the password (but rather have it typed in once by a buddy who knows it – I do and shall not know it), so I also do not want to have it stored in plaintext.  Is it possible to replace the password="<somepassword>" entry by a hashsum of the password, preferably generated without the password  being shown? If so, how can I do it?  Do I have to create an additional hash if MS-CHAPv2 is used? (In the other answer I read something about NtPasswordHash, which didn’t yield much duckduckgo-results and couldn’t be found in the wpa_supplicant.conf man pages as suggested in the other question.)  Alternatively: Is it possible to let a buddy type in his log-in data (i.e. identity and password) only once to let me use his account only once for internettt access?


Trying to install trelby by using sudo dpkg -i trelby_2.2_all.deb produces this error:  Selecting previously unselected package trelby. (Reading database ... 267174 files and directories currently installed.) Preparing to unpack trelby_2.2_all.deb ... Unpacking trelby (2.2) ... dpkg: dependency problems prevent configuration of trelby:  trelby depends on python-wxgtk2.8; however:   Package python-wxgtk2.8 is not installed.  dpkg: error processing package trelby (--install):  dependency problems - leaving unconfigured Processing triggers for gnome-menus (3.13.3-6ubuntu3) ... Processing triggers for desktop-file-utils (0.22-1ubuntu5) ... Processing triggers for mime-support (3.59ubuntu1) ... Errors were encountered while processing:  trelby   It clearly looks like a dependency issue, but I don't know how to resolve this.  Any ideas?


How do I clear Bash's cache of paths to executables?

When I execute a program without specifying the full path to the executable, and Bash must search the directories in $PATH to find the binary, it seems that Bash remembers the path in some sort of cache. For example, I installed a build of Subversion from source to /usr/local, then typed svnsync help at the Bash prompt. Bash located the binary /usr/local/bin/svnsync for "svnsync" and executed it. Then when I deleted the installation of Subversion in /usr/local and re-ran svnsync help, Bash responds:  bash: /usr/local/bin/svnsync: No such file or directory   But, when I start a new instance of Bash, it finds and executes /usr/bin/svnsync.  How do I clear the cache of paths to executables?


Recovering deleted emails on IMAP server with Thunderbird

I have an IMAP mail server and use Thunderbird as my client.  I didn't understand the sychronization of client-server using IMAP vs POP.  My IMAP server was filling up, so I logged onto the server and deleted the Inbox thinking that Thunderbird had local copies of the mail.  When I opened Thunderbird, it synched against the IMAP server and marked all my email as deleted.  The emails still exist in the {path}/thunderbird/profile/default/INBOX file fortunately.  After some research on the net, I edited that file and changed all the “X-Mozilla-Status:0001" to "“X-Mozilla-Status:0000".  When I brought Thunderbird back up, the emails were still gone.  Does anyone know how to recover these?


What is the beginning state for Q in a SR latch?

In this diagram     what would be the beginning state for Q?  Since the first NOR for S and R rely on previous results, there must be something for the first iteration?  NOTE: I'm in a first year digital logic class, so the question is for theoretical use (table making, various homework problems it applies to, etc.), not actual implementation.  Just for things like "if R is __ and S is __ what is Q?"  Simple things like that.


How do you combine two different blender files?

I have one file with a scene containing animation in one file and in the other file I have an object with armature. Is there any way I can bring the object with the armature into the file with the animated scene?


If time stops at the event horizon, can we ever detect two black holes merging? In other words, if you are a short distance away, would you encounter a spherically symmetric gravitational field, or a dipole field?


Let $X$ be adapted integrand, for which we know that $E[\int_0^T X_s^2 \, ds]< \infty $. Let $0≤s<t≤T$ and we have some $W∈F_s$ ($F_s$ is $\sigma$-algebra) and we know $E[\int_s^t W^2X_u^2 \, du]<\infty$. I have to show  that $\int_s^t W X_u \, dB_u=W \int_s^t X_u dBu$.  I know that for simple integrands this follows from definition. We also know that for $X$ there exists sequence of elementary integrands $X^n$ such that $E[ \int_0^t (X^n_u-X_u)^2 \, du]$ converges to $0$, when $n \to \infty$. From this one can see that it also holds $E[ (\int_0^t (X^n_u-X_u) \, dB_u)^2]$. I wonder if I can show that it  holds $E[ |(\int_s^t W (X^n_u-X_u) \, dB_u)|] \to 0$ as $n \to \infty$ . (I think I should use Cauchy- Schwarz inequality: $E(XY)^2 \leq E(X^2)E(Y^2)$, but not sure where. If I could show this convergence in $L^1$, it would be enough for my proof. If I rewrite it as $E[E[|(\int_s^t W(X^n_u-X_u) \, dB_u)|  \mid F_s]]$ I don't know if I can put $W$ out of integral. Would it be correct? Any help would be really very appreciated. Thanks.


Why do people omit the definite article?

I'm used to always hearing or seeing a  before certain nouns.  Yet on certain occasions the article is totally omitted, and it bothers me.  I'm wondering what the justification for omitting the article is, especially when the definite article would seem to be required, or if it is just bad English either on the part of the individual in question or more likely by tradition.  The most frequent place I hear this is at the doctor or dentist's office. In every one I have ever visited, the receptionist or assistant always says things like "Doctor will see you shortly" instead of "The doctor will see you shortly."  The wikipedia article linked above says this: "A definite article indicates that its noun is a particular one (or ones) identifiable to the listener".  In the case of a clinical setting, I know who the doctor is, especially if this is not my first visit.  The people in the office know the doctor even better than I, so it would seem to be inappropriate to omit the article. Even the indefinite article would be incorrect. It further says, under "Zero article":  "In languages having a definite article, the lack of an article specifically indicates that the noun is indefinite."  Since the noun is not indefinite, why are they omitting the article?  Another place I see the article omitted is with the word "bar".  Bartenders apparently don't say "I tend the bar" they say "I tend bar".  Unless a bartender works in multiple bars, it would seem like an article would be required.  Furthermore, "the bar" can mean any bar a person goes to, so even in a case like , it seems like the word "the" should be in the sentence.  The only thing I can think of in this case is maybe the speaker doesn't want to confuse the listener into thinking they work in the legal field.  Is this just a bad habit, a historical corruption or tradition, or is there really a valid reason (or perhaps more than one) for these omissions?


I want to set the caption font for all tables in the document (so I want to do it in the preamble, and not have to specify it in each table) to use uppercase letter (not sc, the small case already provided by the caption package). I have tried declaring the caption font with "\uppercase", "\MakeUppercase", "\MakeTextUppercase" but to no success (also all combinations with {} at the end as shown in preamble below). Any suggestions?   Here is my preamble:   \documentclass[a4paper, 11pt]{article}  \usepackage{textcase} \usepackage[]{caption} \def\tablename{TABLE} \DeclareCaptionFont{up}{\MakeTextUppercase{}} \captionsetup[table]{     labelsep=period,     justification=centering,     font=up, }  \begin{document}   Many thanks :)


why is $\dfrac{dr}{r~d\theta} = \cot \psi$?

why is $\dfrac{dr}{r~d\theta} = \cot \psi$ ?  Extracted from Ordinary Differential Equations, Garrett Birkhoff, in the chapter  of Linear Fractional Equations (First order Differential Equations).  When solving an homogeneous linear fractional equation $$\frac{dy}{dx}=\frac{cx+dy}{ax+by}$$  We came up with:  $$\frac{dv}{F(v)-v}=\frac{dx}{x}=d(\ln x)$$ where $v={y\over x}$  Finding the solution of $x$ is straightforward. However, I do not understand when we "introduce polar coordinates".  The book says: $x=r \sin\theta$ and $y=r \cos\theta$. If $\psi=\gamma - \theta$ is the angle between the tangent direction $\gamma$ and the radial direction $\theta$, then:  $$\frac{dr}{r~d\theta} = \cot \psi$$  Also, why do we do that? is it equal to $d (\ln(x))$? May you explain it?


What are the best ways to improve a site's position in Google?

What are the best ways to improve a site's position in the Google search results?


Why are the fighting me? Skyrim Special Edition-Xbox one

So I just got done killing a dragon with Farkas, So I go back to the companions, and they start fighting me! I did nothing wrong, and im very confused- is it a bug? It’s only two people. Farkas and his twin brother seem cool, there just staring at me- what do I do? I’m playing Skyrim on Xbox. This is random-but for some reason, I’m in love with Farkas, anyone else?


Since upgrading my user's crontab has been wiped out. This is not the first time this has happened this year and it's a pain restoring it each time.  I'd like to be able to back up the crontab for my user but for that I need to know where it's stored.


I am Canadian Permanent Resident with an Indian passport.I have a multi entry UK business visa which is for valid for 2 years but I have not used to enter to UK as of now.I am planning to travel from Canada to India on a personal visit.My wife who is also a permanent resident and indian passport holder plus my daughter who is also a permanent resident of canada with indian passport are travelling with me.We have flight from Halifax to London and the connecting flight from London to Delhi.The London to delhi flight is after 16 hours .The date of landing in london is Dec 1st while ongoing journey flight to india is on next calendar day.My question is that would we all require UK visa  for transit or since I do have business visa,I do not require visa.Also my son who is a canadian passport is travelling with us.I understand for him we do not need visa.


shutdownd service missing on Ubuntu server 16 LTS

Following Rinzwind's kind advice as to how to detect a pending scheduled shutdown, I hit the following problem (on a fairly fresh Ubuntu 64bit 16.04.1 server install):  root@m________a:~# lsb_release -a No LSB modules are available. Distributor ID: Ubuntu Description:    Ubuntu 16.04.1 LTS Release:    16.04 Codename:   xenial root@m________a:~# shutdown +5 Shutdown scheduled for Sun 2016-10-16 20:18:40 BST, use 'shutdown -c' to cancel. root@m________a:~# systemctl status systemd-shutdownd.service ● systemd-shutdownd.service    Loaded: not-found (Reason: No such file or directory)    Active: inactive (dead) root@m________a:~#    Yes, I have systemd-suspend.service, and also -halt, -poweroff, and -reboot services.  Where is the shutdown service?  Shutdown still works!


Is it OK to add [Solved] to the title of a question?

I was confused when I saw this Question with [Solved] in its title where I couldn't find a solution: .  Then I found out that the "[Solved]" part was put there by someone else through editing like these:       I was feeling that this was not how it's supposed to be done and searched meta to find, that it is indeed discouraged to do so:        But on the other hand, the user who did the edits has a whole lot of reputation so I might me missing something here. So what's the correct thing to do? Should those edits be reverted?


I have 3 levels in my information architecture for my hamburger mobile menu. First level: 5 items Second level: 8 - 10 items in total Third level: 6 items Would you use an accordion style or a sequential drill down menu? and why?


What is the essence of electric charge? Is it an independent object carried by the charged particles, or simply some kind of property of charged particles?


Can the adjectivized nouns have a plural form?

Good day! Explain it to me please:)  Is is right to say:  Five-storeys houses  or  Five-storey houses?  Thanks a lot!


Can I prevent home screen shortcuts from getting deleted or moved around?

I had recently gifted my Mom a Nexus 7, with a hope that she will like to read books. She is old with poor eye sight and can't read English that great. I find her eager to learn and she had made a good progress in reading few books. Since she is not used to these gadgets, I am trying to keep settings in  her tablet constant. Recently I observed that the shortcut in home screen for PDF reader disappeared and resulting in discontinued  reading till my arrival. The frequency of this sort of interruption has increased now a days. Rather than finding how the shortcut is being deleted, I think preventing changes to home screen is sensible.  Hence, I would like to know about any means to keep the icons or shortcuts in  home screen  and in launcher  constant, immune to long press and drag and drop operations.  Device info: Nexus 7, running stock 4.2.1, unrooted, but willing to root if required.


How to use search and update cursor on two tables to update values?

I would like to read the values from the company field of linefc, if the values from this field in table then a the WORSTOFFENDER field should be updated with the value YES, if it is not, then NO.  What needs to be added to complete this?  with arcpy.da.SearchCursor(linefc,["Company"]) as cursor:     for row in cursor:         linecur =row[0]  with arcpy.da.SearchCursor(table,["DAMAGING_PARTY"]) as tablecursor:     for tablerow in tablecursor:         tablecur =  tablerow[0]   print "DONE"


I want to write a query similar to this:  Select * from table where EMPLID = 1 OR EMPLID = 2 OR EMPLID = 3 OR EMPLID = 4;   Is there any easy way to break this down or do I have to use OR for each case?


"was" or "were" in the context of "X wishes that he [was / were] Y"

If you are saying that somebody wishes that they could have been somebody else, which would be more correct:  E from the eels wishes he was Elliott Smith  or  E from the eels wishes he were Elliott Smith?


How do I evaluate $\int_{-R}^{R} \sqrt{R^2-x^2}\,dx$ using the change of variables $x = R\sin(w)$?

I'm trying to answer this question from my calculus 1 exam I did last December. The question asks us to compute a definite integral by using the following change of variables $$ x=R \sin(w)$$ in the following equation: $$\int_{-R}^R \sqrt{R^2-x^2} \  dx $$ The thing that's confusing me is how to do this change of variable if the equation is already expressed in terms of $x$?


In the situation where we have:  It used to be thought that...  We use the past tense with the verb that follows since it's something in the past. But what if the following is meant to be a fact?  I came into a question that says:  It used to be thought that the Earth is flat. It used to be thought that the Earth was flat.  Aside from the piece of information in the sentence, it represents a fact(Earth is flat) which makes the tense simple present. I believe that the correct one is is, am I right or not?  Thanks in advance.


How to find the mode of a probability density function?

Inspired by my other , I would like to ask how does one find the mode of a probability density function (PDF) of a function $f(x)$?  Is there any "cook-book" procedure for this? Apparently, this task is much more difficult than it seems at first.


When can I use a temporary IFS for field splitting?

In bash, say you have var=a.b.c., then:  $ IFS=. printf "%s\n" $var a.b.c   However, such a usage of IFS does take effect while creating an array:  $ IFS=. arr=($var) $ printf "%s\n" "${arr[@]}" a b c   This is very convenient, sure, but where is this documented? A quick reading of the sections on  or  in the Bash documentation does not give any indication either way. A search for IFS through  doesn't provide any hints about this effect either.  I'm not sure when I can reliably do:  IFS=x do something   And expect that IFS will affect field splitting.


So I accidentally left my defrosting turky in sink of cold water in my cold garage for 24hrs as a work emergency came up. I am wondering if it will still be safe to cook? it feels cold. Ugh..I have nothing else for dinner today.


How to understand Cauchy's proof of AM-GM inequality(the last step)

The AM-GM inequality: $$a_1a_2\cdots a_n\leq\left(\frac{a_1+\cdots + a_n}{n}\right)^n$$  the trivial case: $a_1a_2 \leq \left(\frac{a_1+a_2}{2}\right)^2 $ is self-evident.  then cauchy use this fact repeatedly. He get: $$a_1a_2\cdots a_{2^m} \leq \left(\frac{a_1+a_2+\cdots +a_{2^m}}{2^m}\right)^{2^m}.\tag{$\ast$}$$  This is easy to understand, and natural, but next step:  he let  $$b_1 = a_1,\ b_2=a_2,\ \ldots,\  b_n=a_n,\  b_{n+1}=\cdots=b_{2^m}=\frac{a_1+a_2+\cdots a_n}{n}$$  replace $a_1, a_2,\ldots ,a_{2^m}$ with $b_1, b_2, \ldots b_{2^m}$ in $(\ast)$ and simplified both left and right. He get the answer. I can repeat his proof, but I don't know why Cauchy can got this idea. How does he got it?


How to use supplementary -ing clauses at the end of sentences

I'm wondering how to use those "(noun-y) -ing clauses" when they are at the end of the sentence.  Most grammar references I've found on the internet only talk about their use as adverbials at the beginning of a sentence. For example:     1) Wanting more money, he accepted the offer.   But I've seen many times people put them at the end of sentences:     2) He issued an attack on her at the company, describing her as an amateurish programmer.      3) She ran all the way to the playground, her friends following.   In these last two examples above, the -ing clauses don't look like adverbials to me. They can be paraphrased as separate sentences. I feel like, because they are related, instead of writing two separate sentences, the writer combines them together.  Grammatically, what are those types of -ing clauses called? And when is it appropriate to use them?


If a player forgets to create a token creature during upkeep, do they get to do it during their opponent's turn?

For instance, Player 1 has  on their battlefield, which has the ability: At the beginning of your upkeep, if you control six or more lands, create a 5/5 red Dragon creature token with flying. If Player 1 fails to create the token creature during their turn, can they create it during the Player 2's turn (and block an attacker with it), or create two token creatures on their next turn? I love playing this game, but the fights my 11-year-old son and I get into sometimes are nuts!


Unwanted striations and shadows on flat surfaces

So I consistently experience this problem where faces have weird shading on the surface. I just want the surfaces to be uniform in texture (like a default plane). I have attached screenshots below. The first one has this weird shading error where there's that shadow on the uipper right corner. The second one has these striations that show the edges on the face. How do I get rid of these?


This is a spin-off question from .   says this on the subject of storage order (clustered index) and the output order     A lot of people believe that a clustered index guarantees a sort order on output. But that's not what it does; it guarantees a storage order on disk.   See, for example, .   I've read the blog post by Hugo Kornelis and understands that an index doesn't guarantee that the sql server reads the records in a specific order. Yet I have a hard time accepting that I can't assume this for my scenario?  CREATE TABLE [dbo].[SensorValues](   [DeviceId] [int] NOT NULL,   [SensorId] [int] NOT NULL,   [SensorValue] [int] NOT NULL,   [Date] [int] NOT NULL, CONSTRAINT [PK_SensorValues] PRIMARY KEY CLUSTERED  (   [DeviceId] ASC,   [SensorId] ASC,   [Date] DESC ) WITH (     FILLFACTOR=75,     DATA_COMPRESSION = PAGE,     PAD_INDEX = OFF,     STATISTICS_NORECOMPUTE = OFF,     SORT_IN_TEMPDB = OFF,     IGNORE_DUP_KEY = OFF,     ONLINE = OFF,     ALLOW_ROW_LOCKS = ON,     ALLOW_PAGE_LOCKS = ON)   ON [MyPartitioningScheme]([Date])   My original query was this:  SELECT TOP 1 SensorValue   FROM SensorValues   WHERE SensorId = 53     AND DeviceId = 3819     AND Date < 1339225010   ORDER BY Date DESC   But I suggest that I could as well use this one (read below for my explanation):  SELECT TOP 1 SensorValue   FROM SensorValues   WHERE SensorId = 53     AND DeviceId = 3819     AND Date < 1339225010   As you can see, my table rows are small (16bytes) and I've got only one index, a clustered. In my scenario, the table consists of 100.000.000 records at this moment (and this will most likely increase tenfold).  When the database server queries this table it has two ways of finding my rows, either it seeks the primary key and thereby reading and returning my values in desc. order of Date, or it has to do a full table scan. My conclusion is that a full table scan on all those records will be way too slow and the database server will therefore always seek the table via its primary key and thereby returning the values sorted by Date DESC


How do you check if a sequence of numbers is truly random?

Suppose a source produces an indefinite sequence of positive integers. How can you check whether the numbers are generated truly randomly?


The absolute value of importance is not very helpful, than how to calculate the relative importance of variables in a random forests Regression

I have used a random forest model for regression analysis. Now, I am having difficulty in working out what can be used in measuring variable importance.  The importance function provides the mean decrease in accuracy and the mean decrease in MSE.   the question is:  why the absolute value of importance is not very helpful and how to build relative importance values.


In beta plus decay proton gets converted to neutron-- where does the extra mass come from?

Beta plus decay seems to be violating law of conservation of mass-energy-- when a proton changes to neutron a very small quantity of Mass is added to the right side of equation -- but where does this mass come from?


What's another name for a circular continuum?

A continuum is anything that gradually changes from one thing to another. But I want another word that describes something that changes gradually and whose opposite extremes are actually one and the same.   Have you ever seen one of those apple charts that describes the many different varieties of apples from sweet to tart? . They call it a spectrum, but a spectrum is not necessarily circular.  If the best answer to my question is "circular continuum" or "circular spectrum", so be it. But if anyone can think of a better word or phrase, I'd be interested to hear it.


How to delete all the files with a certain extension from a folder and all of its subfolders?

I want to remove all the .jpg files from my Music folder in order to save room. My Music folder contains subfolders, and I would like to know if there is a command to remove all the .jpg files from all these folders regardless of their level. Thanks for your help!


Let $H \triangleleft G$ such that $[G:H]=n$. Show that $g^n \in H$ for all $g \in G$.   So I've been trying this for a while and got to nowhere. So I tried to solve it by arriving to a contradiction. So take $g \in G$ such that $g^n \notin H$. Then if  $G=\bigcup_{i=0}^{n-1}Hg^i$,  I was able to arrive to a contradiction. However I wasn't able to prove that $Hg^j \cap Hg^k = \emptyset$ for every $0 \leq k,j \leq n-1$ as to be able to write $G$ as that disjoint union of coclases.  Am I on the right track? Is that true? Any hint if not?  Edit:     The idea is not to use the quotient group. It's an exercise of a chapter of Rotman's Introduction to Theory of Groups which is previous to the introduction to the quotient group.


Enable ADB and/or change USB connection mode on Galaxy S7 w/ broken screen

My Galaxy S7 Edge has a broken screen (totally black, and doesn't respond to touch). However, the phone does turn on and is recognized by Kies 3 and SmartSwitch. I am also able to unlock the phone via thumbprint (sometimes), or via OTG USB keyboard input (always).  The problem is that the USB connection mode is PTP, and I can't see the screen to change it to MTP so that SmartSwitch can retrieve data from the device.  I don't have USB debugging enabled on the device, so I can't change the settings that way.  And since the S6, there's no video output, so I can't buy an MHL+OTG adapter to view the output on a TV and change the settings via mouse.   I've tried booting into recovery mode by holding volume down + power + main button for 30 seconds, but nothing seems to happen. Even if I get into recovery mode, I'm not sure if I can enable ADB, and if that setting would persist after a restart.  I've also called Samsung support, which was useless.  Are there any options for me to either enable ADB, change the USB connection mode, or send video output to another display?


Do presentations given during interviews count as invited talks?

I am in the process of interviewing for faculty positions and trying to keep my CV up to date as I go.  Should I include research (or teaching) presentations given during on-campus interviews as invited talks? Or are they considered just a part of the interview process and better left off the CV?


Is it correct to say e.g. "I like your way of wearing" or "the way you wear looks perfect"?  Is it politely? Is it in use or not? May I use "the way you wear" referring to whole wearings including dress, scarf, hat, bracelet. jewellery, etc?  Thank you for your suggestions in advance.


How does the mean influence PCA? What happens if I use PCA on data with a mean $\ne0$?


I have been using the definitions of Dot and Cross products to understand several natural phenomena. What I have not yet understood is that how are these products defined the way they are. Having no idea about how they came about only makes me think that these calculations are miracles.   "They surprisingly work!"   I would like to drift away from my surprise because I am bothered by simple acceptance of the product rules. So, how are these products defined?


Data model value providers in Lightning Components - any insight or links to more information?

The  documentation mentions these value providers:     Value providers include m (data from model), v (attribute data from   component), and c (controller action).   but I have only ever seen v. and c. in examples.  (In AngularJS 1.x, the model is simple JavaScript objects and the view updates based on the model. Something closer to that in Lightning Components would be welcome.)  Anyone have any insight or links to information about m.?


Prove that $(G, \circ)$ is a group if $a\circ x = b$ and $x\circ a = b$ have unique solutions

I have some difficulties with a task in algebra. I guess it's trivial and really easy but I can't figure out how to solve it.  I have a set $G$ and a binary operation on it, let it be $\circ$. I have that the operation is associative and that the equations $a\circ x = b$ and $x\circ a = b$ have unique solutions. I have to prove that $(G, \circ)$ is a group.  I already have that the operation is binary and associative, so I have to prove that there is unique identity element and unique inverse element and it will come from the equations, but how exactly?


Converting CDF file to NetCDF file to use in ArcMap?

This is a GIS question as well as a Remote Sensing question. I have downloaded CDF files from the ESA from MyEarth online and want to use them in ArcMap. In ArcMap you can Make NetCDF a Raster Layer. Is there some way I can convert CDF to NetCDF? Or do I need to? Should a CDF file work here?


Will the following code result in a deadlock using C# on .NET?   class MyClass  {     private object lockObj = new object();      public void Foo()     {         lock(lockObj)         {               Bar();         }     }      public void Bar()     {         lock(lockObj)         {            // Do something          }     }         }


Windows 11 - Minimum system requirements

I've a Omen , I try  and this is the result  About Minimum system requirements ⚪ =  , ✔ = My system pass , ❌ = My system failed 💻 Processor ⚪ 1 gigahertz (GHz) with 2 64-bit processor or System on a Chip (SoC) ✔ Intel® Core™ i7-7700HQ (2.8 GHz base frequency, up to 3.8 GHz with Intel® Turbo Boost Technology, 6 MB cache, 4 cores) 💽 Memory and Storage ⚪ 4 GB RAM and 64 GB storage ✔ 16 GB RAM and 256 SSD + 4TB HHD ⚙ Firmware and TPM ⚪ UEFI, Secure Boot capable and TPM v2.0 ✔ UEFI and Secure Boot are enable on bios and TPM is 2.0 right ? ( in according with image or maybe wrong ???)  🖥 Graphics card and Monitor ⚪ DirectX 12 compatible graphics / WDDM 2.x and Display >9” with HD Resolution (720p) ✔ DirectX 12 with WDDM and first display 15" fullhd ( notebook ) and external 23" fullhd How to understand what missing for pass PC Health ?


Let $E$ be an $n$-dimensional vector space and $F_1,\ldots, F_k$ be linear subspaces of $E$ such that $$\sum_{i=1}^k \dim F_i > n(k-1)$$ Prove $\displaystyle \cap_{i=1}^k F_i \neq \{0\}$.  I find this problem quite puzzling. The condition $\sum_{i=1}^k \dim F_i > n(k-1)$ says that $\sum_{i=1}^k \dim F_i$ is close to its best upper bound so the $F_i$ have relatively big dimensions. I haven't made any progress on this one. I feel there's some trick involved.


I Made some Random Int in C#    Random rnd = new Random();                 int guess = rnd.Next(0, 11);                  int guess1 = rnd.Next(0, 11);                    int guess2 = rnd.Next(0, 11);                 int guess3 = rnd.Next(0, 11);   but I don't know what should I do if I want to have not repeat Number ?!?! (Its for guess number game)


$G$ be a non-nilpotent and supersoluble and 2-maximal subgroup of G permutes with all 3-maximal subgroup of G

Let $G$ be a non-nilpotent and supersoluble finite group.  $G=Q\ltimes P$, Where $P$ is a  group of order $p^{2}$($p$ is prime), all maximal subgroups of $P$ are normal in $G$, $Q=\langle a\rangle$ is a cyclic $q$-group ($q\neq p$) of order $|Q|>q$ and $C_{Q}(P)=\langle a^{q} \rangle$  Then every $2$-maximal subgroup of $G$ permutes with all $3$-maximal subgroup of $G$.  A subgroup $H$ of a group $G$ is called $2$-maximal (or second maximal )in $G$ if $H$ is a maximal subgroup of some maximal subgroup $M$ of $G$.


Should I be concerned about non planar quads like these if I'm modeling for unity?

I'm currently learning modeling for my game, below is a mesh I'm working on which will be part of my character model for unity.    I suspect the scaling in the front face will cause some distortion for the connecting faces, so I use the mesh clean up tools split non-planar faces    So the connecting two faces are indeed non-planar faces. I tried to fix it but there's no easy way at least for my current knowledge of modeling. Should I take care of it before I export it to Unity or this kind of non planar face is OK for game models?   I tried to google answers about non planar faces in modeling, the information is mixed as some articles saying non-planar faces are no but some post also says non-planar faces especially for biological objects are not something to be concerned as game engine will split them to triangles eventually, so I'm confused.  Edit: I have read the post , I think my problem here is: this mesh is gonna be a part of a mech, and I also want to keep the polygons low so I'm not sure if subdividing/smoothing it is the way to do it.


I want to style the input button type="file" of the PrimeFaces component <p:fileUpload value="#{dms.fileToUpload}" mode="simple" skinSimple="true" styleClass="chooseFile"/>.     As you can see the whole background of the ` changes and not the input button itself. Is it possible to change the style of the button?  I'm using PrimeFaces 5.1


Prove the existence of order 4 subgroups of order 8 groups

I am participating in an Introductory course in groups and I have the following question:     Let $G$ be a finite group of order $8$. Prove that $G$ has a subgroup of order $4$ and a subgroup of order $2$.   i know how to prove that $G$ has a subgroup of order $2$ but i can't show the existence of a subgroup of order 4. I am only a begginer in groups so please take this into account.


Non-Relatively Prime Polynomials in a Field Extension are Not Relatively Prime in Original Field Either

Hypothesis:  $E$ is a field extension of $F$.  $p, q \in F[x]$ s.t. $p$ and $q$ are not relatively prime over $E$.  Goal:  Show that $p$ and $q$ are not relatively prime over $F$.  Attempt:   Since $p$ and $q$ are not relatively prime over $E$, we have that $\gcd(p,q) \ne 1$ in $E[x]$. Then let $d(x)$ be the greatest common divisor of $p,q$ in $E[x]$ which from (1) satisfies $\deg(d(x)) \ge 1$.   And from here I'm not sure how to proceed.  Since $E$ is just a field extension over $F$, we don't even know if there exist roots of $d(x)$ in $E$, much less $F$.  If necessary, we can extend $E$ to some field $K$ s.t. $K$ possesses all of the roots of $d(x), p(x)$ and $q(x)$ -- but I'm not sure how this helps us.


Is there an application to preview markdown files (.md files) on OSX (for instance on Maverick)?


create an object difference between var x = new and datatype x = new datatype

what is the difference between the following syntax        1.  var dtm = new DataTableManager();       2.  DataTableManager dtm1 = new DataTableManager();   Many thanks,


In bash, what is the safest way to pass variables to another program -- $* or $@?

Can someone explain to me in a concise way what the difference between these two vars is?   What is the safest way to pass variables to another program?   E.g.   #! /bin/bash  # do stuff  # pass variables onto another program java $@


Copy existing property from e.g. Properties window to a custom panel

So if I have this custom panel in the 3D view, is there a way I can take a property from for example the properties window and paste it onto my panel below the "text" prop, without creating a new property?  The reason I do not want to create a new property is because I want them to share all data, such as values, keyframes, drivers etc.        bl_info = {     "name": "",     "description": "",     "author": "",     "version": (0, 0, 1),     "blender": (2, 70, 0),     "location": "",     "warning": "",      "wiki_url": "",     "tracker_url": "",     "category": "" }  import bpy  from bpy.props import (StringProperty,                        BoolProperty,                        IntProperty,                        FloatProperty,                        FloatVectorProperty,                        EnumProperty,                        PointerProperty,                        ) from bpy.types import (Panel,                        Operator,                        AddonPreferences,                        PropertyGroup,                        )   class inouse_Settings(PropertyGroup):      my_bool = BoolProperty(         name="Enable or Disable",         description="A bool property",         default = False)     class UV_OT_my_panel(Panel):     bl_space_type = 'VIEW_3D'     bl_idname = "UV_OT_my_panel"     bl_label = "Custom"     bl_category = "Custom"     bl_region_type = 'TOOLS'      def draw(self, context):          scn = context.scene         mytool = scn.inhouse         layout = self.layout          col = layout.column(align=True)         row = col.row(align = True)         row.prop(mytool, "my_bool", text="Text")       def register():     bpy.utils.register_module(__name__)     bpy.types.Scene.inhouse = PointerProperty(type=inouse_Settings)  def unregister():     bpy.utils.unregister_module(__name__)     del bpy.types.Scene.inhouse  if __name__ == "__main__":     register()


we're currently planning a larger WPF LoB application and i wonder what others think being the best practice for storing lots of UI settings e.g.   Expander States Menu orders Sizing Properties etc...   i don't like the idea of having dozens of stored values using the delivered SettingsProvider (i.e. App.config file) although it can be used to store it in an embedded database using a custom SettingsProvider. being able to use some kind of databinding is also a concern. Has anyone had the same problems?   What did you do to store lots of ui user settings?


Sending variables to a Cloud Page using a push notification

I'm trying to use push with AppInbox/Cloud Pages. I want the Cloud Page that is linked to the push message to be able to display dynamic content based on an attribute for that contact. This page -  - says that it is possible to personalise Cloud Page content but doesn't say how. I've already had a Salesforce support case opened and closed with no luck - apparently it's not their job to assist me with how to do something even if they say something is possible but back it up with no documentation for how it might be done. I've tried the normal way you'd do it from an email, using both the _subscriberkey personalisation string as well as the RequestParameter function with fields from the entry source DE, but neither of these work. Given you're selecting a static Cloud Page when you set up the send and there's no visible way to add attributes, how do you actually get a Cloud Page to pick up these values?


Narita Airport Custom check for tax-free purchased items

I understood that I need to show my purchased item with the form attached on my passport to a custom officer at Narita Airport.  I would like to know where is this custom office located. Based on what I had googled, the custom check for this purchased item is after the check-in counter. This means I have to hand-carry it.  I would like to check-in my purchased items. Is it possible or must I hand-carry the purchased item?  Appreciate anyone's input.


Windows 8.1: Windows cannot be installed to this disk

I am installing windows 8.1 for the ASUS laptop.  I have two drive in the laptop namely:  Drive 1 : 40  GB Drive 2 : 450 GB   At the time of installation I have formated Drive 1 which I was suppose to use for Operating System installation. After I format I am getting an error:  Error:     Note: After googling I came to know that I need to format whole disk and need to convert the type of disk to GPT. But I have an important data in the drive Drive 2. How to resolve this?


I'm self studying from Category Theory in Context by Emily Riehl and have encountered the following question regarding slice categories:     Let $\text{C}$ be a category and $c$ be an object in $\text{C}$. Show that $\text{C}/c \cong (c/(\text{C}^{\text{op}}))^{\text{op}}$    The exercise appears in an chapter that introduces the notion of opposite categories and duality proofs.     My intuition of why the statement is true comes from the following observation:  Let $x,y$ be objects in $\mathbf{C}$ (or equivalently $\mathbf{C}^{\text{op}}$). Let $g^{\text{op}} : c \to y$ and $f^{\text{op}} : c \to x$ be objects in $c/(\mathbf{C}^{\text{op}})$. By the definition of slice category, there exists a morphism $h^{\text{op}} : y \to x$ in $\mathbf{C}^{\text{op}}$ such that the diagram below commutes:  $\hskip2in$   Now the 'corresponding diagram' in the opposite category $(c/(\mathbf{C}^{\text{op}}))^{\text{op}}$ would be:  $\hskip2in$    which, as I understand it, would also be commutative. Now, to me, this indicates:   that the objects in $(c/(\mathbf{C}^{\text{op}}))^{\text{op}}$ are the same as the objects in $\mathbf{C}/c$, namely, a morphism in $\mathbf{C}$ from an object $z \in \mathbf{C}$ to $c$. the commutativity of the seconds diagram describes morphisms $h$ in both $\mathbf{C}/c$ and $(c/(\mathbf{C}^{\text{op}}))^{\text{op}}$ if you reverse the arrows again you return to the same diagram. This makes me think you could construct a map between morphisms by first making a map from $ \mathbf{C}/c \to (\mathbf{C}/c)^{\text{op}} ( \cong c/(\mathbf{C}^{\text{op}}) )$ by $h \mapsto h^{op}$     Now, what I am really looking for is a way to structure a proof. I feel like I have some intuition but am very unsure of how to write it down in a concise way. I am new to category theory so I'm still very much learning how to construct these types of proofs using duality; I feel like what I have written is maybe overkill but I'm trying to be as explicit as possible to make sure I understand everything.  In particular, I don't know how I would get a concrete correspondence between morphisms in the two categories that respects associativity of composition etc.  Any help or pointers would be appreciated!


Is a 2-hour transit time enough to catch a connecting flight in Muscat airport? Both flights are with Oman Air

I am flying from Dubai to India with Oman Air with a layover of 2 hours at Muscat airport. Is 2 hours enough for me to catch my connecting flight from Muscat to New Delhi? My flight from Dubai to Muscat as well as the connecting flight from Muscat to New Delhi are with Oman Air. Do I need to re-check in my luggage? Am I taking a risk or should I take an earlier flight from Dubai to get more layover time to be on the safer side?


Unity game crashing when dialogue with NPC initiated

I have 3 NPCs in my "Game". When the player walks up to any of them, they're supposed to have their own dialogue; I've tested this, and they do.  I tried to create a display that shows this dialogue text using a TextMeshProUGUI attached to a blank GameObject called dialogDisplay (tagged DialogDisplay). There is one DialogDisplay object in the scene that I'm trying to get each of my NPC's to use. I tried to make the display object inactive in the NPC Start() function, and enable it when it's time to display the NPC's next sentence.  When I run my game, I get an error on line 21, where SetActive() is called: "Object Reference Not Set to an Instance of an Object".  Here's the NPC script (DisplayNextSentence() is at the bottom, where dialogDisplay is used):  public class NPC : Character { private bool charInRange; public Dialogue dialogue; public bool talkedTo = false; private Queue<string> sentences; public TextMeshProUGUI textPro; public GameObject dialogDisplay; private bool isTalking;  // Use this for initialization void Start () {     charInRange = false;     textPro = FindObjectOfType<TextMeshProUGUI>();     dialogDisplay = GameObject.FindGameObjectWithTag("DialogDisplay");     dialogDisplay.SetActive(false); }  // Update is called once per frame void Update () {     //if player is in range and presses space, triggers NPC dialogue     if (charInRange && Input.GetKeyDown(KeyCode.Space))     {         TriggerDialogue();     } }  //if Player gameObject is in NPC collider, player is in range void OnTriggerEnter2D(Collider2D other) {     if(other.gameObject.tag == "Player")     {         charInRange = true;     } }  //if player exits NPC collider, player is not in range void OnTriggerExit2D(Collider2D other) {     if (other.gameObject.tag == "Player")     {         charInRange = false;     } }  //if NPC has been talked to before, displays next sentence; if not, loads dialogue and displays first sentence private void TriggerDialogue() {     if (!talkedTo)     {         talkedTo = true;         StartDialogue(dialogue);     }     else     {         DisplayNextSentence();     } }  //loads a queue with lines from Dialogue and displays first sentence public void StartDialogue(Dialogue dialogue) {     sentences = new Queue<string>();      foreach (string sentence in dialogue.sentences)     {         sentences.Enqueue(sentence);     }      DisplayNextSentence(); }  //displays next sentence in the queue public void DisplayNextSentence() {     string sentence;     bool done = false;      //if last sentence in the queue, display it again     if (sentences.Count == 1)     {         sentence = sentences.Peek();         textPro.text = sentence;         Debug.Log(sentence);         return;     }      sentence = sentences.Dequeue();     textPro.text = sentence;     dialogDisplay.SetActive(true);     while (!done) {         Debug.Log("In WHile Looop");         if (Input.GetKeyDown(KeyCode.A))         {             done = true;         }     }     dialogDisplay.SetActive(false); } }   Grateful for any insight or tips you can provide. Happy to provide further information if it helps. Thank you!


I would like to calculate the Riemann sum of $\sin(x)$. Fun starts here:  $$R = \frac{\pi}{n} \sum_{j=1}^n \sin\left(\frac{\pi}{n}\cdot j\right)$$  What would be the simplest way to calculate the sum of $\sin\left(\frac{\pi}{n}\cdot j\right)$, so that one could proceed to evaluating the limit and thus getting the value of the Riemann sum, in other words - the integral?   There maybe a way using $\mathbb{C}$?


I've seen a question in my math book with this explanation above it: "If the product of n positive real numbers is 1, then the sum of these numbers must be more than n". I was wondering if this is correct, and if it is, could someone give an explanation or a proof for it?


Lenovo IdeaPad Flex 2 won’t start up Windows directly from Intel 335 SSD

I recently got a  laptop and want to install an SSD  () from my old machine.  So, right now, whenever I start it, it takes me to a menu where it shows what storage device I want to load from. But regardless of whatever I choose it doesnt load anything, restarts my computer and takes me back to the same menu. In order for me to start Windows I have to go to the BIOS and change SATA controller mode from ACHI to IDE if ACHI was previously chosen or IDE to ACHI if IDE was previously chosen.  What can I do to fix this besides getting a new SSH?   Also, I updated my BIOS and it didn’t make any differences.


I have accidentally created a folder in Windows called "..." (the typescript compiler generated it because of a wrong configuration) and now I cannot remove this folder.  I have tried removing the folder via the explorer (the explorer crashed) and also via command line (del/rmdir). A restart didn't help either.  How can I remove this folder?


Regular Expressions: Email validation - Ensure single occurrence of @

I am using the following regular expression to validate email addresses in my application (Angular 2).   ^[a-zA-Z0-9.!#$%&'+/=?^_`{|}~-]+@[a-zA-Z0-9-]+(?:.[a-zA-Z0-9-]+)$  The validation works fine, however, its failing for email addresses that contain more than one '@' symbol (which should be invalid). e.g.  The following emails pass the check (when they should fail):  john@subaru@ferrari.com john@subaruferrari@.com   We are looking at modifying this pattern (and not using another pattern as this is in use in production and we do not want excessive changes) so as to accommodate the above use cases.   EDIT: Apologies everybody. Added the regex now.Although the existing answers on SO address pretty much the same situation (validating email addresses), however, I am looking just a quick modification the regex I am using.


Object reverts back to non-modified state after joining

I am attempting to make a tree but when I try to join the different components together ctrl J my decimated icospheres revert back to its original shape.  Any idea on how I can solve this?  I also forgot to mention that I am trying to create a low poly tree and that I am still in the learning stages.  The first image is the tree before joining and the second is the tree after joining


Ubuntu 14 - unable to use sudo echo to overwrite files

For ubuntu 12.04 bash scripts, I used to be able to run commands like the example below to overwrite files:  sudo echo 'line1    line2 line3' > /etc/some/config/file.conf   Ever since Ubuntu 14.04, I now have to break it up to get the same behaviour like so:  sudo echo 'line1 line2 line3' | sudo tee /etc/some/config/file.conf   I am guessing this is an extra security measure? Is there some way to go back to the old behaviour?    UPDATE  As some have correctly pointed out, this behaviour is consistent across Ubuntu 12.04 and Ubuntu 14.04. I believe I got mixed but because if one runs the command in a bash script called with sudo, then it executes fine, however, pasting the command into the CLI, it results in permission denied. I was comparing apples with oranges.


Automount local drives on boot and hot-plug

I am trying to automatically mount all readable internal and external drives on boot and on hot-plug if they are not already mounted, preferably as a non-root user.  I cannot use fstab to do this because the drives change too frequently, and udisks2 does not appear to automount devices when the user is not actually logged in locally.  I found a udev ruleset to accomplish something like this , but I have read that mounting via udev rules is a  and doesn't work anyway with systemd.  What would be the proper way to do this on a headless Debian (jessie) system?    Note: I've created this udev rule, but I'm not sure if it's the right way to go about this:  KERNEL!="sd[a-z][0-9]", GOTO="automount_disks_END"  # Check if it is a mountable disk, skip if not IMPORT{program}="/bin/udevadm info --query=property --name=%k" ENV{ID_TYPE}!="disk", GOTO="automount_disks_END" ENV{ID_FS_TYPE}=="", GOTO="automount_disks_END"  # Set mount options ACTION=="add", ENV{mount_options}="nosuid,nodev" ACTION=="add", ENV{ID_BUS}=="ata", ENV{mount_options}="$env{mount_options},rw,dmask=022,fmask=033" ACTION=="add", ENV{ID_BUS}=="usb", ENV{mount_options}="$env{mount_options},ro,noatime,dmask=222,fmask=333"  # Mount the disk ACTION=="add", RUN+="/bin/su - user -c \"/usr/bin/udisksctl mount --block-device /dev/%k --options $env{mount_options} --no-user-interaction\""  # Clean up after removal ACTION=="remove", RUN+="/bin/su - user -c \"/usr/bin/udisksctl unmount --force --block-device /dev/%k --no-user-interaction\""  # Exit LABEL="automount_disks_END"   This rule doesn't solve the authorization check issue for users who are not logged in locally, either.    CLARIFICATION:  What I'm basically looking for is the functionality of usbmount that works for ATA devices and doesn't clutter up the /media directory with unused folders, in short.


How can I switch dialog buttons using the keyboard?

Whenever I'm trying to close a file that has been changed, I get the save file dialog    I remember that the Don't Save button used to have focus, so I could press it using Spacebar, while pressing Enter would click on Save. But now on Lion, I'm unable to find a way to press the Don't Save using keyboard only, since Tab doesn't change focus to anything, and space doesn't work either.  This is the same for all file save dialogs in the system. Is there any way I can press the Don't Save button using keyboard only?


Is it wise for researchers to thank Alexandra Elbakyan (founder of Sci-Hub) in the paper acknowledgements?

founded the site , which allows bypassing publisher paywalls.  If this service is used by researchers to access papers that would otherwise be out of their reach - due to their university not having subscribed to publishers or not being able to buy papers due to budget constraints - is it a good idea / wise to thank Alexandra in the Acknowledgement section of a paper citing the otherwise unattainable papers?  For example, "We would like to thank Alexandra Elbakyan for her work / contributions to science" without explicitly mentioning any specifics.  A similar question was already asked with the top rated answer pointing out that it would be unwise for paper authors to . This seems like a reasonable point.  Reseachers thanking someone for their contribution to science does not seem illegal and might get some readers of a paper to research the background of the acknowledgement.


How can I encrypt and decrypt a string in C#?


I have a machine on 16.04 but need to update it before April 2021. Will 18.04 still be available on software updates up until April 2021?

Like the title says, I have a very stable machine running 16.04 at the moment and I'm thinking of updating it to 18.04 (and then maybe 20.04 after). I will want to go the update route rather than a clean install so will I be able to choose 18.04 from Software Updater up until 16.04's EOL?


Can I have multiple mx records for a domain

I have a domain and I want that if one mx record fails then 2nd mx should takeover for sending and receiving mails.


Unable to implicitly 'wrap' an IEnumerable

Given this class:   public class Wrapper<T> {     public Wrapper(T value)     {         Value = value;     }      public T Value { get; }      public static implicit operator Wrapper<T>(T value)     {         return new Wrapper<T>(value);     } }   This code snippet doesn't compile:  IEnumerable<int> value = new [] { 1, 2, 3 }; Wrapper<IEnumerable<int>> wrapper = value;      error CS0266: Cannot implicitly convert type 'System.Collections.Generic.IEnumerable< int>' to 'Spikes.Implicit.Wrapper< System.Collections.Generic.IEnumerable< int>>'. An explicit conversion exists (are you missing a cast?)   But the compiler is perfectly happy with this:  Wrapper<IEnumerable<int>> wrapper = new [] { 1, 2, 3 };   Why?


Why does delete work but not arrow keys in terminal?

In a linux terminal I use "cat > file.txt" to make a file one line at a time.  What I find is that per-line the delete key works but the arrow keys insert escape codes rather than moving left and right in the line.  Why is this? Is there a reason that the terminals basic action cannot do left and right arrow keys? I know there are things like GNU readline which do it but my question is not about those.


How can we use geometric series in calculating Green's function sum over loop effects

I found Greens function summing over repeated insertion of 1PI in Schwartz p.330: $$ \begin{aligned} iG(\not p)&=\frac{i}{\not p-m}(i\Sigma(\not p))\frac{i}{\not p-m}+\frac{i}{\not p-m}(i\Sigma(\not p))\frac{i}{\not p-m}(i\Sigma(\not p))\frac{i}{\not p-m}+\cdots\\ &=\frac{i}{\not p-m}\left[1+\frac{-\Sigma(\not p)}{\not p-m}+\left(\frac{-\Sigma(\not p)}{\not p-m}\right)^2+...\right]\\ &=\frac{i}{\not p-m}\frac{1}{1+\frac{\Sigma(\not p)}{\not p-m}}\\ &=\frac{i}{\not p -m+\Sigma(\not p)} \end{aligned} $$  It seems to use geometric series assuming $|\frac{-\Sigma(\not p)}{\not p-m}|<1$ from 2nd line to 3rd line. I can't understand how the assumption $\left|\frac{-\Sigma(\not p)}{\not p-m}\right|<1$ is valid for all cases.  If I understand correctly, field renormalization and mass renormalization are done in next page, such that $\Sigma(\not p)$ is 1PI of self-energy before field renormalization. For example, electron self energy up to $e^2$ order in dimensional regularization is $\Sigma(\not p)=\frac{\alpha}{2\pi}\frac{\not p-4m}{\epsilon}$. Obviously as $\epsilon \rightarrow 0$, $|\frac{-\Sigma(\not p)}{\not p-m}|<1$ doesn't seem to hold.  Can anyone explain how I can use geometric series in calculating Green's function? Or is it just divergent and can't I use this?  Also I don't understand the idea of 'repeated insertion of 1PI' because it looks like we can count on the loop effect in a very ordered manner, but I think we need proof to legitimate this counting.


So, I've finally obtained the Werewolf form. After returning out of the form, fully naked...  I seem to be stuck in third person view! How can I fix this? Scrolling or pressing F does not work.  I want to get back in first person view...    Mouse wheel allows to zoom in/out but not get me into the first person view but rather behind and slightly to the right of the character. The command animcam locks me at a certain distance, doing it again brings me back into the mode that I'm stuck in third person view. Hitting F after this doesn't work. tfc doesn't help me either, although that command is nice to take screenshots...


I heard today that deuterium for nuclear fusion could be extracted from the Oceans, in which it is present in "heavy water." I heard this claim:     "Deuterium is distributed uniformly with Ocean depth."   This contradicted my naive expectation that deuterium density would increase with depth, on account of it being in "heavy water." For example, salinity increases with depth. I asked, and received two contradictory explanations.   The first was that because powerful waves and Ocean currents mix Ocean water, gravity is negligible. This surprised me; I thought that Ocean's were stratified, with predominantly tangential, rather than vertical, currents.   The second explanation was that my view of seawater is naive - that I should think of seawater not as heavy and regular water molecules, but as a soup of weakly interacting deuterium, the normal hydrogen isotope and oxygen, forming and breaking water and heavy water molecules with a short time-scale. If so, apparently, deuterium density and the normal hydrogen isotope would be distributed evenly with depth. This did not help me, because, I then naturally wondered why deuterium's density doesn't increase with depth, since it is heavier than hydrogen-1?  Is the claim correct? and if so, what is really going on? I have the feeling that Ocean behaviour with depth might be non-trivial...


Is it acceptable to have a research paper with no references?

I (an undergrad) and 2 other profs from my department have been working on something and we were thinking of submitting our work to a conference (a pretty well known one) this week. The fact is there is no related work that has been done on the problem we are solving and therefore there is no paper which we can cite as a starting point for our work. The only existing things that we make use of are trivial definitions from mathematics (like Riemann Integral) and also definitions that are pretty well known in my area (CS). So again, we do not think there is a need to cite any particular papers for that.   Now my question as stated was - is it acceptable to have a paper with no references? Or do you think we should just mention some papers (we never had to use them) where those definitions were actually proposed?  PS: I'm sure some of you might suggest me to ask those profs. But quite frankly none of them have much experience as far as publishing papers is concerned. So it would be great if some one could give me a good advice and help me out.   Edit: Thanks everyone for the answers. Of course somewhere a little sarcastic and ridiculing, but I can understand since this is a little weird. Actually yes, I had the notion that a paper wasn't worth citing unless I use some results from it (say an algo or some theorem). But I guess that isn't the only reason why I should be referencing as many seem to suggest here. The fact is we had seen quite a few survey papers before we started this out and I was under the impression that there wasn't a need to cite them since anyone could find them. But now, things are bit more clear and I guess I should cite them and I will :)


Add a "flag" button in the revision list

Have a look at revision 6 of . How about adding "flag" buttons for individual revisions? Or should I just flag the question itself, category "other", and specify the revision in the text? (That's what I ended up doing.)


What is the largest number whose first digits can be calculated?

The way to calculate the first digits of $a^b$ is to compute the $log_{10} a$ and multiply by $b$, and find the fractional part. But if there are too many digits in the integer part of the result, then the digits after the point are inaccessible. By too many digits I mean enough digits to overflow a computer's memory. So this question boils down to, how many digits can be represented in a computer's memory?  The largest number I have ever computed the first digits of is $2^{2^{2^{32}}}$ which begins with 315921269337233843004... and has more than $9.34*10^{1292913985}$ digits. It took literally almost all my computer's RAM and 30 hours of my time to calculate.  Is there any hope of eventually finding the first digits of, say, $3^{3^{3^{3^3}}}$ at some point?


Prove a function is constant under certain conditions

Let $f: \mathbb{R} \rightarrow \mathbb{R}$ be smooth and such that for every $x$    $$\int_{-\infty}^{\infty}\frac{|f(x)-f(y)|}{|x-y|^2}dy < \infty$$   Prove that $f$ is constant.


What are the optimal settings to photograph moon/dawn/sunrise/dusk/sunset?

I just got a new camera, a Canon EOS Rebel xti and I am still learning what it can do. What setting or ISO should I use to take a photo of a moon (with/without landscape)? And what setting or ISO do I put it on when I take photos of dawn, sunrise, dusk & sunset?   Taking photos of Moons, Sunrise & sunset are my favorites when it comes to taking photo shots!


I'm having some trouble with polar plots. I generate the plot coordinates using Scilab and then plot them in Latex. I can't figure out how to remove the points (mark = \empty does nothing, but changing the mark with mark=x for example does nothing either), nor can I move the ticks out of the picture. Can anyone help please?  I want to add units to the ticks as well, degrees for the x ticks and dB for the y ticks.  My code is as follows:  \begin{tikzpicture} \begin{polaraxis}[xmin=-90,xmax=90,rotate=90]     \addplot table [x index=0, y index=1,col sep = comma, data cs=polarrad,mark = \empty]{mydata05.csv}; \end{polaraxis} \end{tikzpicture}


Let $B$ be a nilpotent $n\times n$ matrix with complex entries let $A = B-I$ then find $\det(A)$

Let $B$ be a given nilpotent $n\times n$ matrix with complex entries. Let $A = B-I$   find out $\det(A)$. What if B is orthogonal or skew symmetric matrix? Then can we say anything about its trace and determinant?


Why does [A-Z] match lowercase letters in bash?

In all shells I am aware of, rm [A-Z]* removes all files that start with an uppercase letter, but with bash this removes all files that start with a letter.  As this problem exists on Linux and Solaris with bash-3 and bash-4, it cannot be a bug caused by a buggy pattern matcher in libc or a miss-configured locale definition.  Is this strange and risky behavior intended or is this just a bug that exists unfixed since many years?


What is the preferred way to add custom javascript files to the site?

I've already added my scripts, but I wanted to know the preferred way. I just put a <script> tag directly in the header.php of my template.  Is there a preferred method of inserting external or custom js files? How would I bind a js file to a single page? (I have the home page in mind)


Please explain this step in proving the square root of 3 is irrational

Assume that  $$3 = \frac{p^2}{q^2}$$  So,   $$ 3 q^2 = p^2$$  So $p^2$ is divisible by $3$. How we can conclude this?


Does anyone know or recognize this symbol or what it could be associated with on an Android phone? Attached is a screenshot showing five of them.


I need to monitor the network activities of a process and the bandwidth of the connection. So I decided to use nethog and netperf combine with grep and awk to write the values to a file.   nethog command: nethogs -t  eth0 | grep firefox | awk '{ print $3 }' (I want to take the upload/download speed). The 1st problem is that command doesn't print anything.  More detail: command: nethogs -t  eth0 | grep firefox output:  usr/lib/firefox/firefox-bi�)/4956/1000  0.338867    0.239063 /usr/lib/firefox/firefox-bi�)/4956/1000 0.543555    0.274219 /usr/lib/firefox/firefox-bi�)/4956/1000 0.794531    0.489844 /usr/lib/firefox/firefox-bi�)/4956/1000 0.794531    0.489844 /usr/lib/firefox/firefox-bi�)/4956/1000 0.749023    0.589844 /usr/lib/firefox/firefox-bi�)/4956/1000 1.30098 3.47617 /usr/lib/firefox/firefox-bi�)/4956/1000 1.90449 8.0127 /usr/lib/firefox/firefox-bi�)/4956/1000 5.31641 25.0033 /usr/lib/firefox/firefox-bi�)/4956/1000 8.60762 42.0176   I want the two values at the bottom right. But as you can see the output ain't consistent (the space), add | awk '{print $3}' most of the time return nothing. And I can't fix this.  netperf command: netperf -H 192.168.1.10 and the output is:  Recv   Send    Send                           Socket Socket  Message  Elapsed               Size   Size    Size     Time     Throughput   bytes  bytes   bytes    secs.    10^6bits/sec    524288 524288 262144    10.00    **718.62**   I want to print the value on the bottom right but have no idea how to. That's the 2nd problem   Can you guys help me out? Any ideas will be appreciated!


Let $W_1$ and $W_2$ be subspaces of a vector space $V$. Prove that $W_1 \cup W_2$ is subspace of $V$ if and only if $W_1 \subseteq W_2$ or $W_2 \subseteq W_1$  Attempt:  $\boxed {p\Leftarrow q}$   (Almost trivial): Assume $W_1 \subseteq W_2$ then $W_1 \cup W_2=W_2$  and since $W_{1,2}$  are subspaces proof of this side is over.  $\boxed {p\Rightarrow q}$  I couldnot do the direct proof so I wanted to assume otherwise, here is where trouble begins.  I don't know how to take negative statement of the $p\Rightarrow q$ as follows:  Otherwise statement of the  $\boxed {p\Rightarrow q}$   is $W_1 \cup W_2$ is subspace $V$ but $\boxed{\boxed{W_1 \subseteq W_2\; or\; W_2 \subseteq W_1}}$  is wrong.  How can I do the proof in the assumming otherwise, and can you give me hint to prove the theorem (hints or answers, of course, can be other methods.)


80s or possibly early 90s anime with a race of giant caterpillar things

Might not be anime (or just Japanese animation, I don't know the difference).  I don't remember much from this movie other than a brief glimpse of an aerial view of the caterpillars moving like a herd. And the hero (or heroine) who sacrifices him/herself by jumping, or throwing herself/himself in the way of gun/laser fire. There were quick-cut shots of the laser/bullets hitting the character. Then (I believe) the caterpillars somehow heals the hero/heroine.


Adding my launcher to the Unity Launcher automatically. How?

Based on official documentation:     In order to add your launcher to the Unity Launcher on the left, you   select and drag it onto the Launcher panel. Alternatively, you can   place your .desktop file at /usr/share/applications/ or at   ~/.local/share/applications/. After moving your file there, search for   it in the Dash (Windows key -> type the name of the application) and   drag and drop it to the Unity Launcher. Now your launcher (.desktop   file) is locked on the Unity Launcher!   It means, that you can add a launcher manually via "drag and drop". But, is it possible to do this programatically?  I can explain why I am asking about it:   I have my own scpirt, it downloads the latest version of Eclipse IDE, creates eclipse.desktop file without iteraction with User.  And on the last step I want to add Eclipse.desktop file to Unity Launcher and I do not want to ask user to do it.  I analized the spesification for *.desktop files and did get an answer.  Please provide advice.


My Pokemon go logged me out and I tried using the same email I used to login when I first started, but it did not work? How do I get my account back?


It is possible to obtain a injective continuous map $f:\mathbb{R}^m \rightarrow \mathbb{R}^n$ when $m > n$?

Let $T :\mathbb{R}^m \rightarrow \mathbb{R}^n $ be a linear map, where $m > n$. Then, it is possible to prove that there is no $T$ injective in this case. In fact,  if such a map exists the Rank-Nullity Theorem gives us  $$ n \geq \dim Im (T) = m  > n, $$ so, we obtain a contradiction. A natural question arises here:   It is possible to obtain a injective continuous (nonlinear) map  $f:\mathbb{R}^m \rightarrow \mathbb{R}^n$ when $m > n$ ?   I try to construct such an example, but it seems so delicate. There exist some way to prove that a such map does not exist ?


How important are pure math grades for applied math graduate schools?

I'm an applied math/econ major in the U.S. and am looking into pursuing a masters degree in applied math.  This term curiosity got the best of me and I decided to take abstract algebra and I am not doing well at all in the class.  Somehow my professor convinced me to stay and now I am heading closer to C territory after two atrocious midterms.  I am wondering:   How will applied math grad schools look at a C in this class?  I mean I've gotten 1 other B but the rest of my grades are all A's.  In fact I am doing better in Real Analysis than in this class! (shocking, i know.)  A few professors I talked to have said that since this is a pure class and it takes some people some time to understand these concepts so admissions might just shrug it off if everything else looks great. If I do get a C how can I compensate for this grade?  I'm taking a grad class in quantum computing concurrently and doing really well.  if I take another grad course that uses abstract algebra (i.e. model theory) will it be enough to demonstrate to admissions that I am still worth considering as an applicant? I have quite a bit of research experience, studied math abroad and did well and will continue to do more math next term.  But if I don't get into a grad school of my choice how can I repair this grade if it tanks in the future?   Please offer some suggestions as I am literally putting in every ounce of energy to resuscitate this grade...


I have exported osm data using osm2pgrouting in the database, it has SRID 4326. I want to change projection of all the tables created to a particular SRID in UTM.  I read the post  and , but these are only changing SRID withour transforming the coordinates. I am using the command   select UpdateGeometrySRID('Schema Name', 'mytable', 'the_geom', newSRID) ;


One of the unicode characters in my display name disappears in the Stack Exchange Android application

So a few days I ago I thought I would make my display name slightly more unique by changing the last three characters to Latin Letter Small Capitals:  C - U+0043: Latin Capital Letter C  ᴏ - U+1D0F: Latin Letter Small Capital O  ʀ - U+0280: Latin Letter Small Capital R  ʏ - U+028F: Latin Letter Small Capital Y  Surely the change is completely pointless.  That said, I seem to have confused the Android application for Stack Exchange. Here's a screenshot from my LG G3:    The darn O is missing!  I would hope that I can keep my cosmetic name change and not have to be known as  "Cry" :). Is this is a bug, or have I picked a non-standard Latin Letter Small Capital O?


Let's say I have a 1 meter steel rod floating in the vacuum of deep space far from any significant gravitational force, and at rest relative to myself.  Say I apply some force perpendicular to it and near one end:  |==============|   ^   |   |   Clearly the bar will remain within the plane of the bar and the force.  Within that plane, will the rod rotate about its center of mass, move entirely together with some veloctiy in the direction of the force, or a little of both?  If a little of both, how can we calculate how much of each as a function of the strength of the force?


Mounted device taking up space on Ubuntu

I have an Ubuntu based Droplet on DigitalOcean which has 25GB of Storage. I am using it to run Backups from 2 different Machines.    Backup 1 is going to /home/server1/ (should have a total of 25GB of disk available) Backup 2 is goint to /mnt/volume_sgp1_01/server2/ (this should be the VOLUMES part of 200GB)   Since 25GB are not enough for my scope I have added a VOLUMES plan, which gave me an additional 200GB on a mounted drive, the problem now however seems that the mounted device also takes up space on the main droplet. Here an example:      4.0K    lib64     4.0K    media     4.0K    opt     4.0K    srv     8.0K    snap     16K     lost+found     32K     root     40K     tmp     608K    run     5.3M    etc     15M     bin     15M     sbin     76M     boot     171M    lib     855M    usr     1.3G    var     6.5G    home     14G     mnt     23G     total   The 14GB of mnt seem to be used / allocated on my Droplet as well, however that should not be the case.  I have added the SPACES (mnt) using the original instructions being:      # Create a mount point for your volume:     $ mkdir -p /mnt/volume_sgp1_01      # Mount your volume at the newly-created mount point:     $ mount -o discard,defaults,noatime /dev/disk/by-id/scsi-0DO_Volume_volume-sgp1-01 /mnt/volume_sgp1_01      # Change fstab so the volume will be mounted after a reboot     $ echo '/dev/disk/by-id/scsi-0DO_Volume_volume-sgp1-01 /mnt/volume_sgp1_01 ext4 defaults,nofail,discard 0 0' | sudo tee -a /etc/fstab   I am not really a LINUX expert, however I think there is definately something wrong here, perhaps I mounted it incorrectly or why is mnt using up disk space on my 25GB? Some expert help would be really appreciated. Thank you!


I'm trying to build a 555 timer with a 50% duty cycle.  I followed the instructions given  (pg 12).  I used a 470 microfarad capacitor, 150 ohm resistor and a kohm resistor. The output voltage is always low.  I've attached an image of my current circuit and would appreciate it if someone could pinpoint what I'm doing wrong.


Name of a story about a man who is colonized by microscopic aliens

A man is injured in a explosion and later he realizes that he has become the host of a whole civilization of aliens.  The aliens help him repair himself physically and provide him with help and advice.  The one thing that they will not let him do is shave with a blade because a nick would cause thousands of alien deaths so he must use an electric razor.  The man eventually finds a woman who is also infected with the same kind of aliens.  They go on a bender with alcohol and drugs resulting in the death of the woman but the man barely recovers. He finds out to his regret that all the aliens inside of him have been killed due to the alcohol and drug fueled episode.   This was a novella or short story from the late 60's or early 70's.


Sum of two eigenvectors for different eigenvalues

Let $V$ be a $k$-vector space and $f\in\text{End}(V)$. Assume that we have eigenvectors $v,w$ of $f$ for different eigenvalues and choose $a,b\in k\setminus\{0\}$. Claim. $av+bw$ is not an eigenvector of $f$.  Choose $\lambda,\mu$ eigenvalues for $v,w$. We get $$f(av+bw)=af(v)+bf(w)=a\lambda v+b\mu w .$$ If there is an $\alpha$ with $f(av+bw)=\alpha(av+bw)$ then we would get $$a\lambda v+b\mu w=\alpha av+\alpha bw\Rightarrow (\lambda -\alpha)av+(\mu -\alpha)bw=0.$$ I think this won't help. Any other ideas?


For any composite modulus $n$, there are two consecutive integers whose product $\equiv 0 \bmod n$

I was considering the properties of factorials in the following context:  Wilson's Theorem affords a simplistic, exact, but impractical, algorithm for the prime number counting function $\pi (n)$ because for $k\ge 5$, $(k-1)!\equiv 0 \bmod k$ if $k$ is composite, and $(k-1)!\equiv -1 \bmod k$ if $k$ is prime. The requirement for $k\ge 5$ arises because the number $4$ behaves idiosyncratically: $3!\equiv 2 \bmod 4$. Making allowance for the two primes $2,3$, we can say $$\pi (n)=2-\sum_{k=5}^n((k-1)! \bmod k)$$ For each prime greater than $3$, the sum is augmented by $-1$, and for each composite greater than $5$, $0$ is added. Adding the negative of the sum to $2$ (corresponding to the primes $2,3$) affords an exact count of primes up to $n$. Alas, this algorithm is highly inefficient due to the huge amount of computation required as $n$ increases. As a matter of minor interest, this approach yields a similar algorithm for counting composite numbers up to $n$: $$1+\sum_{k=5}^n(((k-1)! \bmod k)+1)$$ Here, the outside $1$ accounts for the composite number $4$, and the summand is $(-1+1)=0$ when $k$ is prime, and $(0+1)=1$ when $k$ is composite.   In thinking about shortcuts that might mitigate the computation of factorials, I observed (looking at several examples, using numbers small enough to permit hand calculation) that there seems always to be some positive integer $1<a<a+1<n-1$ such that $a(a+1)\equiv 0 \bmod n$ when $n$ is composite. It is plain that this relationship cannot be true when $n$ is prime. Although the relationship holds for all of the specific examples I examined, I have not been able to work out a general proof (or disproof) of the statement.  In writing this post, I found several previous questions that came close to this question but none that addressed it.   My questions are: 1. Is  it true that $\exists a \ | \ (1<a<a+1<n-1)$ such that $a(a+1)\equiv 0 \bmod n$ when $n$ is composite? 2. Can anyone in  the community provide a proof, disproof, or counterexample? 3. If true, is this observation already known? Where might I find literature or references about it?


I take the definition of the Fourier transform of $f \in L^2 (\mathbb{R}^3)$ to be   $$ \widehat{f} (k) = \int\limits_{\mathbb{R}^3} e^{-2 \pi i k \cdot x} f(x) dx $$  Question: Can we say anything useful about $\widehat{|f|}$ in terms of $\widehat{f}$?