"He needn't say" / "He doesn't need to say"

When I studied English at school (in Italy, more than 35 years ago), we were taught a rule according to which one should say, e. g., "He needn't (need not) say", but NOT "He doesn't need to say".  If I'm not mistaken, it was explained to us that the rule holds good with the following limitations:  1) only in the negative form: thus, "He needn't say", but "He needs to say", and "Does he need to say?";  2) only in the present tense: thus, "He needn't say", but "He didn't (won't, wouldn't, etc.) need to say";  3) only when an infinitive follows: thus, "He needn't see a doctor", but "He doesn't need a doctor".  But, if I google "doesn't need to", I find 125,000,000 occurrences.  I was wondering: does the rule hold good more for British than for American English?  Also, perhaps it isn't an absolute rule, and both constructions ("He needn't say" and "He doesn't need to say") are possible.  Is the rule at least a good description of the circumstances when we CAN (but needn't necessarily) use this construction?  Thank you very much, for this and the other answers.


I've never supported Apple in any way, but I like their hardware. As I've just purchased and got working a nice Apple wireless keyboard (bought second-hand!), I'm curious about the possibility of buying a second-hand MacBook and installing Ubuntu on it.   What, of what's important, isn't working? Notably, I do Flash Player development from time to time, so I do at the very least need to get a 32-bit debug player installed. (I usually run 64-bit, so I'm familiar with having to tweak things to get it all working properly) I'd also need to be able to play DVDs with CSS, run Google Chrome, etc. Is it fairly similar in capabilities as a non-Apple computer as far as what I can use? It seems that there's a different architecture used, namely PowerPC, and I don't know what this means to me as an end-user.   Can anyone recommend me for or against installing Ubuntu on MacBookPro?


Should you use hamburger / hidden navigation on larger desktop sized screens?

I've seen a lot of sites hiding their nav on desktop and simply showing a hamburger-esque menu. Obviously this looks more "minimal" But I can't help to think this isn't the best approach from a UX perspective. Does anybody have any opinions, data, or studies to prove either way?


Hi, Im newbie at blender 3d.   I just saw this at motion graphic, but don't understand how to model this shape.   Can I get any advise for modeling this shape?


What's the legal way to stream music online?

It's really hard getting a definite answer on this so I'm going to ask it here. Is there a legal way to stream new music on a website without getting artist consent first. There seems to be a lot of popular sites like hotnewhiphop.com doing this that are hosting from both the US and Canada so I'm guessing there is a grey area that allows it. For the record I don't allow downloads of the music and simply stream each song in a player.


What is the cardinality of the set of the empty set?

Given set $ A = \{  \emptyset   \}$ what is $|A|$? I just learned about sets today in class and I'm unsure how to answer this.


How do I go from Ubuntu 14.04 to Windows?

I bought a Dell laptop used, and it had Ubuntu 14.04 on it, but I prefer Windows. I noticed that there was a sticker on the corner of my laptop that said "Windows Vista Basic" and another one that says, "Intel Core 2 Duo inside". I would like to switch back to Windows, but I don't know how. Also, I am not able to use a disc to switch because the disc drive doesn't work.


Is it harmful to plug a POE energized data source into non-POE NIC card?

Some of our wired ethernet data connections are energized with  at 48 volts.  But not all of our devices utilize POE.  Is it harmful to plug a device into POE when the device's NIC does not utilize POE?  I would like to use the wired ethernet connection for data on a device which does not utilize POE.


I hit Shift+F4 to get the Blender Python console.     PYTHON INTERACTIVE CONSOLE 3.2.3 (default, Sep 25 2013, 19:38:45)  [GCC 4.7.2]  >>> import numpy Traceback (most recent call last):   File "<blender_console>", line 1, in <module> ImportError: No module named numpy   On the web, I found some instructions that might work, that involved copying my Python3 numpy into the Blender Folder.     Install python3.2 Install numpy for python3.2 using the python3.2 command instead of python on my system numpy was located in /usr/local/lib/python3.2/dist-packages. Copy numpy from there to blender/2.57/scripts/modules   Looking around and with help from  In my case, copied numPy to /usr/lib/blender/modules however it still cannot find.  I may have done some of these steps wrong or not represented them accurately. This is to the best of my memory.


Row row = sheet.getRow(rowNumber) returns java.lang.nullpointer exception even when row exist in Excel sheet. I am using Apache POI

EDIT:   I am using this code to read rows and columns of an excel sheet.But the line marked with double star throws exception(java.lang.nullpointer exception).Apart from this i also want to convert null columns found in between to blank columns.Please help.         There are 2 loops one for row and inner one for column as obvious. Niehter the row is getting read nor the blank cell issue is getting resolved.  public void read(String filePath) throws NullPointerException {                      try {                     FileInputStream file = new FileInputStream(new File(filePath));                     System.out.println("going to create Workbook object to read excel row wise");// Create Workbook instance holding reference to .xlsx file                     XSSFWorkbook workbook = new XSSFWorkbook(file);                     System.out.println("going to create object sheet to read excel row wise");                     XSSFSheet sheet = workbook.getSheetAt(0);  //extracts the first sheet of excel                     System.out.println("Running row iterator to read excel row wise");                      for (int rowNumber = sheet.getFirstRowNum(); rowNumber <= sheet.getLastRowNum(); rowNumber++) {                         if (rowNumber == sheet.getFirstRowNum())// this row was skipped as it was header row.                         {                         System.out.println("skipping first row");                         continue;                         }                         this.rowconcat = ""; // all values of perticular row will be concatinated in this variable.                         this.flag = 0;                          if (sheet.getRow(rowNumber) == null) {                             System.out.println("row detected null");                         } else {                             // The row has data                             System.out.println("row no inside else==="+rowNumber);                             **Row row = sheet.getRow(rowNumber);**  //This line here throws null pointer exception.                         for (int cellNumber = row.getFirstCellNum(); cellNumber <= row.getLastCellNum(); cellNumber++) {                             Cell cell = row.getCell(cellNumber);                             if (cell == null || cell.getCellType() == Cell.CELL_TYPE_BLANK) {                                 this.flag = 1; // set to 1 to indicate blank cell but this also doesn't work                                 cell.setCellType(Cell.CELL_TYPE_STRING);                                 cell.setCellValue(" "); //inserting space in cell after converting its type to String.                                 this.rowconcat = this.rowconcat + cell.getStringCellValue() + "~";                             } else {                                 cell.setCellType(Cell.CELL_TYPE_STRING);                                 this.rowconcat = this.rowconcat + cell.getStringCellValue() + "~";                                 }                             }                         }                     }                 }//try block closure                catch(Exception e){                //autogenerated                 }             } // function closure


When I turn on my PC it starts Windows giving me no choice to use Linux or Windows

I installed Ubuntu on my PC alongside Windows 10 with a USB key. When I turn on my PC it starts Windows; it gives me no choice to use Linux or Windows. What should I do?


Not being able to grasp the way of fscanf reading a float in my program

This would be the part where I do the readings  do {     res=0;     res += fscanf(in , "%50s",recs[n].city);      res += fscanf(in , "%d.%d.%d ", &recs[n].d.d , &recs[n].d.m , &recs[n].d.y);     res += fscanf(in , "%f", &recs[n].t );     recs = realloc(recs, (n+2)*68);     if(!recs){         printf("Error for second recs");         return 0;     }     n++;         }while(res == 5);   My input file :  Germany 8.01.2020 54.24 Romania 1.2.2019 34.55 Banat 5.1.1999 41.66 Region 4.5.2023 51.71 Idk 12.11.1967 91.981   My output :   Germany 8 1 2020 54.240002  Romania 1 2 2019 34.549999  Banat 5 1 1999 41.660000  Region 4 5 2023 51.709999  Idk 12 11 1967 91.981003      So basically my question is why does fscanf reads 51.709999 instead of 51.71 for example.


Saving a String into a file, then loading it into a String variable will give a "different" string that seems to have the exact same name

So I am having an issue, I put my self to the test of creating a 2D sandbox game kind of for fun, but has turned out evolving into something a bit more after about a week, but, to the point, I am saving chunk data into a few files, these are just .file or, just the most basic file type I assume, and the problem persists even using .txt files. So what's happening is after saving a file containing the object name, x, and y positions, I am creating an object in a linked list using that information, when I enter a new "chunk", but things are not exactly right, somehow, my images load up for the tiles correctly, which is handled in the constructor for that tile, being called after it is added to the list, however, what made me notice is I have a check in the tiles update method, to see if it wants to change to a different grass texture, and it doesn't happen, so I did some checking and printing, and well, I can tell that the name variable certainly contains the desired name, eg. "dirt", however it does not equal "dirt", so I thought it was catching some spaces and I even trimmed the String, and when I run a test like   if(name == "dirt")System.out.print("dirt is actually "+name); else System.out.print("dirt is apparently not "+name);  and the result is always, "dirt is apparently not dirt", with no spaces, and even when looking in the actual file I save it to, it saves the name fine, I have them saving in an order like so;  name x y eg.      dirt 0 560 dirt 28 560  and so on, these all load in position perfectly fine and what stumps me is that the initial image loads in correctly, which is quite explicit, a switch statement to determine what the image, material type and such should be..  I was wondering if anyone has come across something like this and what it could possibly be.  Also any code desired I will add to the desc.  (I didn't know so many people would be so quick to help. Thank you all, I know it was a simple problem, but it had me super confused, now thanks to you all I understand something about comparing variables and objects I should have really known before, and which is really important .)


directlua : misinterpretation of % as latex comments

What is the good way to avoid LaTeX interprete % as comments in \directlua ?  Or in this case one must use an auxiliary file ?


Can a wildcard SSL certificate secure host names of various depths?

I discovered recently that my *.domain.com cannot be used on server1.apps.domain.com because it will only "wild" the one level, not two.  The questions are thus twofold:   Is there such a thing as a *.*.domain.com certificate? Would such a certificate work on both server1.apps.domain.com and www.domain.com? (e.g. two different levels of depth)


Short story "The Viewer" (?) 60's-70's (?) Working on image enhanced viewer, man realizes his device can see remote locations and images from the past

Assigned to enhance image quality for a (let's say) viewfinder, a developer is puzzled when the display seems to show movement when no one else is in the room.  Figures out that the device is seeing through walls.  Refines device and still gets unexpected imagery.  Discovers that the device can display images from any distance and time in the past.  Realizing the consequences of the technology, he produces a few and goes to elaborate lengths to hide his identity, selling them in consignment shops. Instructions said to point in the desired direction and adjust DISTANCE knob appropriately, but always leave TIME knob set on zero.  The device becomes ubiquitous, displaces many other technologies, eliminates crime; advanced computer tracking coupled with the viewer solves ancient mysteries and reveals the identity of the developer after his death.


Nonzero ground state energy of the quantum harmonic oscillator

Since $\frac{1}{2}\hbar \omega$ is the  of the ground state of the harmonic oscillator, then there is no way to extract this energy.  Therefore, in what way is this value different from zero? Is not it just about where we decide to choose the reference point?


Suppose we have two charged shells with a distance between the two centers that they cannot be considered as point-like charges in the mutual interaction, for example three times the radius. Can we still calculate the force between the two spheres by thinking of them as charges concentrated in their center? and why?


Read SQLite Database from download folder and retrieve information

I am very new to android development and have some problems about application. I have a database in Download folder named database.sqlite, this database contains name, surname, age and job. I want my application to read database from Download folder and print retrieved information to text view. I want to execute query when I click on find button: SELECT * FROM NAMES WHERE name="John" AND surname="Doe";, Name and Surname should be got from editText control.  Here's my activity.xml:  <?xml version="1.0" encoding="utf-8"?>     <TextView         android:layout_width="wrap_content"         android:layout_height="wrap_content"         android:text="Enter Name, Surname" android:id="@+id/textView" android:fontFamily="sans-serif"/> <EditText         android:layout_width="wrap_content"         android:layout_height="wrap_content"         android:inputType="textPersonName"         android:ems="10"         android:backgroundTint="@android:color/holo_green_light"         android:layout_marginTop="13dp" android:id="@+id/editText"         android:layout_below="@+id/textView" android:layout_alignParentStart="true"         android:hint="Name"/> <EditText         android:layout_width="wrap_content"         android:layout_height="wrap_content"         android:inputType="textPersonName"         android:ems="10"         android:backgroundTint="@android:color/holo_green_light"         android:id="@+id/editText2"         android:layout_below="@+id/editText" android:layout_alignParentStart="true" android:hint="Surname"/> <Button         android:text="Find"         android:layout_width="wrap_content"         android:layout_height="wrap_content"         android:id="@+id/button2" android:layout_alignTop="@+id/editText" android:layout_alignParentEnd="true"         android:layout_toEndOf="@+id/editText" android:layout_alignBottom="@+id/editText2"         android:textAllCaps="false"/> <ListView         android:layout_width="match_parent"         android:layout_height="match_parent"         android:layout_below="@+id/editText2" android:layout_alignParentStart="true"/>     I tried other solutions from here, but failed, The database 1 GB, I use API 25  Thanks for attention, please help


Compare String array elements to literals Strings

What am I doing wrong in here:  public void processFinish(String[] result) {     System.out.println(result[0]);     System.out.println(result[1]);     System.out.println(result[2]);      if(result[0] == "true")         comments.setText("Success");     else if (result[1] == "true" && result[2] == "false")         comments.setText("Username is already used");     else         comments.setText("Phone number is already used"); }   The output is: true false false  Yet, it always executes the else clause !!!


I need to copy a hiddden dot directory from remote to local. I tried this:  scp ssh:/home/ubuntu/.gnupg/ /local/target   But this gives me an error scp: /home/ubuntu/.gnupg: not a regular file


Why do you want to "View your basic profile info"?

I have been logging into SE using my Google account and SE have always asked to "View your email address".  Today it also asked for "basic profile info":    This is a NEW development (I was not asked for "basic profile info 3 days ago).  What has happened?  I do not want to divulge my "basic profile info".  What are my options?  Can I create an SE account and move my old account history over?


What is the advantage of local classes in Java or in any other language that makes use of this feature?


Q:Who is to activate Singing Bell Strike's ability? Who controls this Aura?

is, in my opinion, a really peculiar Aura, from the point of view of ruling's exceptions.    While the controller of the Aura remains the one who cast it, it is also true that the ability granted to the enchanted creature can be activated by the creature's controller only.    What happens, then, if after casting Singing Bell on an opponent's creature, I cast , choosing the opponent controlling a creature enchanted by Singing Bell   Singing Bell Strike returns to its owner's hand Singing Bell Strike goes to the graveyard   Although i think the correct answer is 2,I question it just the same because it is not easy to entangle like others. This question is different from others, in the way that a beginner may do not understand that paying the activation cost of an Aura placed on an opponent's creature does not mean that the Aura's controller is the opponent itself.  There is a point in the rule 303.4e : -"Only the Aura’s controller can activate its abilities" - that can be read in ways that lead to bad interpretations of this situation, and this in my opinion should be clarified.


Simplifying the expression of a product of inner products

Let $\mathbf{v}=(v_1,\cdots,v_n)^T, \mathbf{w}=(w_1,\cdots,w_n)^T, \mathbf{a}=(a_1,\cdots,a_n)^T     \in\mathbb{R}^n$, and let  $$ A = (\mathbf{w}\cdot\mathbf{a})(\mathbf{v}\cdot\mathbf{a})=\left(\sum_{i=1}^{n}w_ia_i\right)\left(\sum_{j=1}^{n}v_ja_j\right) $$ Is there any way of simplifying this quantity? Into one sum, maybe?


What will be Summation $\sum_{n=1}^{\infty}\frac{n^2}{n!}$

I break it down into two parts the numerator one into $\dfrac{n(n+1)(2n+1)}{ 6}$ but what should be summation of $n!$ ?


Recommendation for a precalculus textbook

I'm a high school senior interested in pursuing a major in quantitative economics, which I understand is heavily math-intensive. However, as it stands, my academic strengths are more verbal (780 on SAT) than mathematical (630 on SAT). Therefore, I'd much like to increase my skills at math and plan to devote a great deal of my summer studying from a precalculus textbook or two. That's where you good people at Math Stack Exchange come in. I'm hoping some of you could recommend a precalculus level textbook that has the potential to initiate a neophyte such as myself to the math world. Bonus points if you can recommend a textbook that somehow also has applications to economics.   By the way, I actually have already purchased a precalculus level textbook, the University of Chicago School Mathematics Project's Precalculus and Discrete Mathematics, but am of the understanding that it is more of a primer text and thus would be wisely supplemented by something a little more in-depth. This might be helpful to take into consideration as well. I asked this same question at Math Overflow and was told that the site is more reserved for research-level mathematics, and was referred here instead, so I hope this is the right domain for this sort of question. Many thanks for any and all replies.


Transparent elements are different than viewport when saved as .png

I am working on a project where I composed many layers with an transparent background. Now I rendered the whole thing and when I saved it the result looked different than the saved version (The white background of the second image is alpha but opened with spacebar on mac)


If $G/N$ is nilpotent and $N\leq Z(G)$, then $G$ is nilpotent

It seems to me that I didn't need the condition that $N\leq Z(G)$, since I can just prove the theorem by simply applying third isomorphism theorem on a central series of $G/N$.  What am I missing here?  My proof:  Take a central series of $G/N$: $1\unlhd G_0/N \unlhd G_1/N \unlhd ... \unlhd G/N$. Then we have $(G_i/N)/(G_{i-1}/N) \cong G_i/G_{i-1}$ (by third isomorphism theorem) $\cong Z((G/N)/(G_{i-1}/N)) \cong Z(G/G_{i-1})$ (by third isomorphism theorem).  Also $G_i \unlhd G$ by correspondence theorem from $G_i/N \unlhd G/N$.


If $P$ and $Q$ are distinct primes, how to prove that $\sqrt{PQ}$ is irrational?

$P$ and $Q$ are two distinct prime numbers. How can I prove that $\sqrt{PQ}$ is an irrational number?


No, really — should the logo tag be renamed to logo-language?

Stack Overflow has a “” tag for questions about the programming language Logo, and a “” tag for questions about logos (e.g. getting them to display correctly on web pages).  Yesterday I looked at how many questions used each tag:   logo: ~80 graphical-logo: ~85   However, around 50 of the questions tagged “logo” (almost all of which were in the most recent 50) were referring to graphical logos, rather than the programming language. I went through and corrected them (it was a slow afternoon at work), leaving:   logo: 30 graphical logo: 135   It seems that, at least recently, when users type “logo” into the tag field, they’re almost always talking about graphical logos, not Logo the language, but don’t realise that graphical-logo is the appropriate tag.  I know this isn’t by any means a big problem, but I was wondering whether renaming the tags (from “logo” to “logo-language”, and “graphical-logo” to “logo”), or possibly doing some sort of special-case thing in the tag autocomplete, might result in fewer mis-tagged logo/Logo questions.  Previously suggested here:


How to store a version sequence per product

I need to create a table like the following one:  +----+---------+---------+ | Id | Product | Version | +----+---------+---------+ |  1 |       1 |       1 | |  2 |       1 |       2 | |  3 |       2 |       1 | |  4 |       1 |       3 | |  5 |       2 |       2 | +----+---------+---------+   Where ID is an Identity(1,1) and I need the Version to be auto-populated depending on being inserted Product.  A similar effect could be achieved upon SELECT by using ROW_NUMBER() with PARTITION like this:  SELECT ID, Product, ROW_NUMBER() OVER(PARTITION BY Product ORDER BY ID) AS Version FROM Products   What are my options?


Is the likelihood in Bayes theorem a probability?

First some notation and definitions: In the Bayes formula as written for machine learning applications, $$    p(\theta|D) = \frac{ p(D|\theta) p(\theta) }{ p(D) } $$ commonly $p(\theta)$ is labeled the prior, $p(D|\theta)$ is called the likelihood, and $p(D)$ is called the evidence (or marginal likelihood I think).  Elsewhere (in various books), the likelihood is defined as $$    p(D|\theta) $$ viewed as a function of $\theta$, not of $D$.  But $\int p(D|\theta) d\theta$ does not necessarily integrate to one, and therefore is not a probability density. As support, in the Bishop Pattern Recognition & Machine Learing book p.22, "Note that the likelihood is not a probability distribution over w, and its integral with respect to w does not (necessarily) equal one."    On the other hand, I believe $\int p(D|\theta) d D$ does integrate to one. But this is the integral of a conditional probability, not a likelihood.   Finally the question: is the likelihood in the Bayes formula really a likelihood (since a likelihood is not a probability)?  If not, why is it called a likelihood?  If so, how can a non-probability appear in this formula that calculates the posterior probability?  How to think about this?  (In fact I have a theory about what the answer is, but since I am self learning I hope to hear a better and complete explanation rather than an answer "yea that's right", from which I would learn nothing)


SSH connection refused from inside my LAN

I'm on Fedora 19 and I have a problem with ssh.  Ssh is up and running and I can connect when I enter my lan ip. But when I try my server name (blahblah.no-ip.org) I get a connection refused. No-ip is already running as a service and is working properly (sending the correct ip).  I've already set up port forwarding on my router, I also changed the port of ssh both on the service and on the router port forwarding (in case my beloved ISP decided to block those ports). But still I get a connection refused and when I nmap the hostname I see that the ssh port is closed.  One thing though: I have two PCs under the same external ip (I've set up the port forwarding to the correct internal ip). When I nmap blahblah.no-ip.org I get a Port 23 and 80 open. 80 seems OK but I've never started telnet service on my machine.  Any ideas what else to try? Router is zte zxv10 and port forwarding is correctly set up. I say this because I've already set up port forwarding for deluge and it's working properly.


I'm a terribe novice when it comes to electronics and I've got a question: I have a simple circuit including a photocell that regulates current (I hope this terminology is correct). It works as it should: The more light, the more current flows.  Now I am looking for some opposite device: A schematic / device / photocell (?) that increases its resistance the more light is applied.  Is there something like that? I'd be gracious for any help.  edit details:  I'm quite sure that what I'm doing is a total no-go, but somehow it's working anyhow (i'd be glad for any tip you guys have :)).. My super-simple (dangerous?) circuit consists of a 9V battery and a power-led. in between their connection I simply placed a photocell. As mentioned, I'd like this photocell to work in opposite of its current function: Power-led should become brighter if I "close up" the photocell.   thanks a ton so far!


How can I install Photoshop CS6 on Ubuntu 16.04?

I have some problems with installing Photoshop CS6 on Ubuntu 16.04 through Wine.   My installation starts fine but at end of the charging it displaying an error.


Dropbox error - 'echo 100000 | sudo tee / proc/sys/fs/inotify/max_user_watches'

Dropbox gives me an error that mentions echo tee 100000 but then it disappears. How to fix or remove msg?


I’m not a professional academician by any means. I’m just a medical student trying to write a paper in my spare time.  I don’t have an excellent grasp of the literature in this field. A lot of the information I’m learning comes from a single excellent review article/book chapter.  Here lies my question. This book chapter will say, e.g., ”such and such [1][2]”. Do I just cite the book chapter when I describe such and such in my background? I think not; I should probably cite [1], [2], or both.  So, the real question: is it OK/acceptable/ethical to just believe that [1] and [2] contain such and such; and just cite them without actually reading the papers? To be able to do this would save me quite a bit of time.


Calculation of sums using Fourier series

I will start my with an example, followed by questions based on this example, and then general questions that could apply to a general case.  Calculate the sum : $\sum_{n=1}^\infty \frac 1 {n^6}$  The solution uses the function $$f(x)=\begin{cases} x(\pi-x),&x\in[0,\pi]\\ x(\pi+x) , &x\in[-\pi,0]\end{cases}$$ $f$ is an odd function, so all of the even fourier coefficients are $0$, and all of the coefficients of the odd terms will be imaginary. Calculating the coefficients gives : $$\hat f_0=\frac 1 {2\pi}\int_{-\pi}^{\pi}f(t)dt=0$$  since $f$ is odd and the domain is symmetric around $0$, for $n\neq0$ we get : $$\hat f_n=\frac 1 {2\pi}\int_{-\pi}^{\pi}f(t)e^{-int}dt=\frac 1 {2\pi}\int_{-\pi}^{\pi}f(t)(\cos(nt)+i\sin(nt))dt=\\ =\frac 1 {2\pi}\left[\int_{-\pi}^{\pi}f(t)(\cos(nt))dt+\int_{-\pi}^{\pi}f(t)(i\sin(nt))dt\right]=\frac 1 {2\pi}\int_{-\pi}^{\pi}f(t)(i\sin(nt))dt$$  since $f(t)\cos(nt)$ is odd and the integral over a symmetric domain around $0$ is $0$.  Using integration by parts twice we get $$\hat f_n=\frac {2i((-1)^n-1)} {\pi n^3}$$ which means $$\hat f_n=\begin{cases}0 ,&\in\mathbb{N}_{odd} \\ -\frac {4i} {\pi n^3}&\text{otherwise}\end{cases}$$  and we get $$f(x) \sim \sum_{n=-\infty}^{\infty} e^{inx}\hat f_n$$ Using Parseval's identity we eventually get $$\|f\|^2=\sum_{n=-\infty}^{\infty}-\frac {4i} {\pi (2n+1)^3}$$ from here , we can evaluate the norm (it's a simple integral) and do several algebraic manipulations to the series and find the sum we wanted. This is a fairly straightforward and simple method if you have the right $f(x)$ for your sum.  My questions are about the construction of $f$:    $f$ is an odd function. In my understanding, $f$ was constructed this way just to simplfy the calculations ? Could we choose $f$ to be an even function and the calculations would be as easy? Could we choose $f$ to be neither even nor odd and still be able to calculate it simply? $f$ is a polynomial of degree 2. This means we will integrate by parts twice,resulting in a fourier coefficient in a degree of $\frac 1 {n^3}$. So in the case we want to calculate $\frac 1 {n^6}$ we will get the right degree from Parseval's identity. Does the fact that $f$ is even or odd affects this stage? For example, I've seen the even function  $$f(x)=x^2$$ on the interval $[−π,π]$ gives coefficients which are of degree 2. What if we wanted to calculate $$\sum _{n=1}^\infty \frac 1     {n^{2k}}$$ Would we choose $f(x)$ to be of degree $k$ and use the same method? Would another way to calcultate $$\sum _{n=1}^\infty \frac 1 {n^{k}}$$ be to pick $f$ polynomial of degree $(k-1)$ that converges pointwise at $0$ (or maybe other "nice" number like $0.5\pi,\pi$)? Is it even possible? The idea is to evaluate $$f(0)=\sum _{n=-\infty}^{\infty} \hat f_n e^{in0}$$   The next question is related to Paseval's Identity:   Can Pasevals Identity be generalized to $L_p$ norms? $$||f||_{L_p}^p=\sum_{n=-\infty}^{\infty}|\hat f_n|^p$$   If so, if the fourier series converges uniformly$^*$ to $f$, can we calculate sums using this generalized identity?  $(*)$-I haven`t gotten deep into Functional Analysis, but it does make sense to me that if the convergence is uniform then there is convergence to the function in any $L_p$ norm  I hope my questions are clear and I`m sorry for the long question.  Edit: Note that I`m not interested in help with the specific example I wrote down, I understand how to calculate the sum. I'm more interested in the general case and the construction of $f$, and the properties of $f$ that allows us to calculate the sum easily. The specific series I adressed to is only an example to show the method I was using. (And hopefully to be more clear with my question).Any answers on this specific case that can be generalized would be appriciated as well.


Is it unethical to access journal articles from Torrent websites?

Getting access to journal articles can be quite expensive, in particular for those not affiliated with some University (even then, it's still expensive, it's just the uni paying the cost...).  A question asked on this site  ponders why this is so. The answer is not convincing at all, it essentially says "that's just the way it is, pay up".  Well, if that is the way it is gonna by, then I am just going to torrent-download the articles. How could this possibly be unethical, if you guys yourselves, for no good reason and for the detriment of scientific inquiry, help support the monopoly that these journals have?


I've read this excellent post:   ...But I'm having trouble finding one that meets my criteria. Hopefully someone with some hands-on experience can save me the weeks of trying each package :)  This is what I'm looking for:   Scheduling so I can run a weekly backup Backup must cover the ENTIRE system for a quick restore in a jam. Similar to Clonezilla. Prefer bootable USB/CD to restore from   If anyone is familiar with Acronis in Windows, I'm looking for something like that. Set it to 1AM Friday mornings, and let it do its thing. If I hose my Ubuntu install, I pop in a USB stick, punch in my NAS address, and let it restore.  Thanks for any input!


Finding a homormorphism form $\mathbb{Z}/4\mathbb{Z}$ to $\mathbb{Z}/6\mathbb{Z}$

I've got the following question: find a homormorphism form $\mathbb{Z}/4\mathbb{Z}$ to $\mathbb{Z}/6\mathbb{Z}$.  My work so far: The group $\mathbb{Z}/N\mathbb{Z}$ has a generator of 1, so: If we have a homomorphism from $\mathbb{Z}/4\mathbb{Z}$ to $\mathbb{Z}/6\mathbb{Z}$ which sends $1 \in \mathbb{Z}/4\mathbb{Z}$ to an $m\in \mathbb{Z}/6\mathbb{Z}$ with $m \cdot 4=\bar{0}$ , does this mean that if $4m=\bar{0}$ in $\mathbb{Z}/6\mathbb{Z}$ implies $2m=\bar{0}$ and thus $m=0 \mod 2$? How should i finish this? Does this mean that there are three homomorphisms, namely you can send 1 t0 0, 2 and 4? I have read another question regarding the homomorphisms between $\mathbb{Z}/n\mathbb{Z}$ and $\mathbb{Z}/m\mathbb{Z}$, but when I tried to apply it, I got stuck


How many possible ways are there to seat down 20 men and 20 women on a bench of length 40, such that no two women are adjacent?  At first I was sure the answer was 20!*20!. Because we seat down the women first with spacing between them, and choose their placement. Then we seat down the men and choose their position. Turns out the answer is :  21*20!*20!  I dont understand why ?


how to make a memory hungry application cause swap slowness only to itself?

I have 6GB RAM and 10GB swap. Some applications dare to consume/allocate/use about 5GB to 6GB of RAM.    When the memory completely fills out, the whole system hangs for 1 to 2 minutes to swap all inactive (and active) appplications, what is really troublesome because to access again some simple applications that consume less than 100MB, I have to wait about 10s to it be put on RAM again (well, all that is how I see it works out of my usage experience).  So, my goal is: put that single application under leash, restrict it to keep the whole system fast and stable.


How to find out a file is hard link or symlink?

I have a file in ~/file.txt.  I have created a hard link by :  ln ~/file.txt ~/test/hardfile.txt   and a symlink file :  ln -s ~/file.txt ~/test/symfile.txt   Now,   How can I find out that which file is hard link ? How can I find out hard link follows which file?   We can find symlink file by ->, but what about hard link?


Attach files from Google Docs directly from Gmail

This question may in some respect, resemble , but the answers there didn't answer my question.  I often find myself wanting to attach documents stored in Google Docs to my GMail mails, but unfortunately I know only two ways of doing it.   Download the file, and then attach it. Send a mail, directly from Google Docs   What I want is to attach the document from within GMail itself.  There are a number of reasons for this.   Attaching multiple documents is impossible from google docs site. Attaching a document to a reply is impossible without downloading the file from Google Docs.   As per the discussion in , attaching a Google Doc directly from GMail is not possible, but the posts there are almost a year old.  So, if anyone knows of a way of doing this, please help out.


My Auntie died unexpectedly without leaving her icloud information (pretty standard!) I've restored her ipad as I thought it would reset her passcode as I couldn't guess it but now it's asking for Apple ID. I've tried everything but I can't guess her secret info or get into her emails until I go see my grandad and get her phone (he literally lives at the other side of the country.) So now I have this ipad and my cousin has iPod touch which is acting as a paper weight. There must be a way around it as this must be a fairly common thing surely? I don't have her death certificate, there isn't a will and my grandad (next of Kin) is 86 and quite flustered about everything and he's about had enough.   Ive looked online for a bypass but no luck, as it's not reported stolen surely it can't have an anti theft lock?  Thank you


Can I install the Cinnamon DE on Ubuntu GNOME? If so, how?

First, I would like to know if I can install the Cinnamon DE without messing up Ubuntu GNOME.   Second, I would like to know how to install the Cinnamon DE.  Lastly, I would like to know how I would access Cinnamon after installing.


Logistic regression, separating variable (moderator) true in population!

I already checked other posts in this area, but still couldn't get a fit to my issue: I have the following preconditions:  Software: preferred SPSS v21, possibly R Sample size: 5655 (will get around 8x times larger in 2 weeks, but I already want to find out statistical pitfalls) DV: binary; 1 = success, rest 0 = fail - sales conversion IV1: categorical; 5 different conditions - different designs IV2: categorical; 3 different conditions - different discount (0,5,10)  and the following problem:  DV = 1 has only 36 cases. IV2 is naturally related to DV, since one of the 3 conditions of IV2 is only applied when DV = 1. Meaning for all DV = 0, IV2 will also equal 0. Conditions of IV1 are randomly assigned to each case. Essentially, I want to find out whether IV2 is a moderator of IV1 -> DV, however, SPSS gives me very strange pseudo-R²s, odds ratios and so on.  After googling I found out it might be a problem of quasi-complete separation. Subsequently, I tried to run Firth logistic regression in SPSS, which never stopped running and in R, which gave me the following error:     Error in chol.default(x) :    the leading minor of order 15 is not positive definite   Such that I have the following questions:   is my issue solely related to the sample size? how can I fix the leading minor error? how can I approach the problem in general (methods)?   Additional info: The different discounts (IV2) are applied to a specific set of products (let's call them set A (0 discount), set B (5 discount) and set C (10 discount)).  Now a visitor comes and is randomly assigned to one of the categories of IV1, which is effecting how A, B and C are displayed to the visitor.  It is only tracked to which category of IV1 the visitor was assigned and which product (from set A, B, C or none of them) was purchased.  I only want to find out the conversion rate of A, B and C and especially which category of IV1 predicts a higher conversion. On top I assume the discount (IV2) to have a moderating effect on the effects of IV1.  I know its probably not optimal to do it like this, but it was not possible in another way. Maybe my reasoning is incorrect, but I hoped to test the above for a moderation effect.   I ran a bayesglm today, it indeed drove down the odds ratios, so that is already a little success, although the results are mostly insignificant, which is probably due to the small sample size. However, I am not even sure whether the bayesglm applies to my situation. Further, I am unsure about the prior means and scales which I am trying to understand at the moment. Any feedback of how I can approach my situation is welcome, thanks!


How do I resize a partition to make more room in the root

I am upgrading to 13.10 and discovered my root partition was too small. I used partition editor to shrink my home partition by 2GB. Now I want to take the unallocated space and add it to sda1. I can't figure out how to accomplish this.  (This is an old question where I found an answer - below. It has been suggested that it is a duplicate of , but this isn't exactly the case. I was using gparted but my problem turned out to be connected to the swap.)


The sum of the harmonic series and the negative harmonic series

I haven't been able to find an answer to this on here or elsewhere, so I apologize if I missed it.   Here's what I know:   The harmonic series $\sum_{n=1}^\infty \frac1n$ diverges. The negative harmonic series $\sum_{n=1}^\infty -\frac1n$ diverges. The terms $\frac1n$ and $-\frac1n$ cancel each other out for all n. The sum of two divergent series is divergent.    So the question is: what is $\sum_{n=1}^\infty \frac1n$ + $\sum_{n=1}^\infty -\frac1n$? 0 or divergent?  If divergent is the answer, I am curious if there is any more reason other than definition.  If the answer is convergent to 0, I am curious on a more detailed answer other than simply "the terms cancel out".  Additionally, we can extend this question to integrals as well: Does $\int_1^\infty\frac1x$ + $\int_1^\infty-\frac1x$ = 0 or is it divergent?  Thanks for your time and help.


How can I change the icon of an application?

I installed numix icon theme and now I want to change icons for applications (such as LibreOffice, Firefox, etc).  Is this possible? How?


Determine resultant velocity of an elastic particle-particle collision in 3d space

So I have two particles that have collided in 3 dimensional space. I want the particles to rebound off of each other in an elastic manner. How do I determine the resultant velocity vector if I know: Both particles' initial velocity vector, their masses, and their initial position vectors relative to the origin.  I tried to follow the instructions on  but I am not sure how to make their equations work without polar coordinates / how to translate my data to polar coordinates.  Also, if you answer my question in terms of polar coordinates, can you explain which angle is theta and which is phi? Since there are 2 different conventions, I am not really sure which angle is being referred to in the explanation on the aforementioned website.  EDIT: This isn't for a class. I'm writing a physics engine for a gravity simulation I am making using Unity. I haven't taken kinematics since I was in high school, which is why I am so rusty.


I would like to know how I can permanently remove GWX from my machine. I am running Windows 7 currently, I have removed the KB3035583 update, which did remove the system tray icon for a few days, but it has come back. According to the accepted answer in  question, removing the GWX directory may also be necessary, but I am not able to even though I am the admin, I get a message saying that I need permission from trustedinstaller, and cannot change permissions for some reason. I have also attempted this in Safe Mode with no luck.   Is it something simple that I'm missing?


How to best keep a bunch of coriander fresh?

I bought this bunch of coriander at my local fruit shop. What is the best way to keep it fresh as long as possible? I usually cut off about 1 cm of the stems and then put them into a glass of water, at room temperature. I wonder if I would be better off putting them into the fridge, with or without the water. Or if there is another option I'm unaware of.


What is the max level of a character in Destiny?

I haven't seen any players over level 25 yet.  What is the level cap in Destiny ?


Is there any plan to introduce a hierarchical tag model to accommodate version-specific tags?

When I visit stackoverflow.com I'm mostly interested in Python-related questions, so naturally  is the first tag I search for, but then I feel compelled to also check out , , and  just so that I don't miss any topics that are only tagged with python of a specific version, but are still clearly related to Python in general.  These are three unnecessary extra page clicks I have to go through every time I visit the site just because I'm interested in Python. I'm pretty sure I'm not the only one who's bothered by having to do this, and it leaves questions tagged with just a version-specific Python under-exposed.  Is there any plan to introduce a hierarchical tag model such that it allows either:   Searching for a broader term automatically searches for more specific terms, e.g. searching for the tag python-3.x automatically includes topics tagged with python-3.6, and searching for python automatically includes topics tagged with python-2.7 and python-3.x (and therefore, hierarchically, python-3.6), or, Tagging a more specific term automatically tags broader terms, e.g. when a user tags a question with python-3.6, the site automatically also adds tags python-3.x and therefore python to the question?   Please note that this differs from tag synonyms because what's needed here is a hierarchical relationship between tags, not equivalency. So in option 1, searching for python-3.x also searches for python-3.6, but does not search for python, and in option 2, tagging a question with python-3.x also tags python, but doesn't automatically tag python-3.6.  Thanks for your considerations.


Spawn away from spawn block that was set by /setworldspawn

I am making a custom map and I want to set the world spawn. Whenever use the /setworldspawn command, it never spawns me on the correct block. You will see this at play in this short slide show. First I set the spawn, then I kill myself to check it. As you see in the second photo, I don't spawn on the glass block.  SETTING SPAWN:   SPAWNING:   Does anybody know of an easy way to fix this?


what is the area of the region [ (x,y):0<x , y<1 , 3/4<x+y<3/2 ] do'nt use area of triangle & squares by conventional method?

I was confused with the answer provided on  since it doesn't fit the expected answer given in a multiple choice question:  (A) 9/16 (B) 7/16 (C) 13/32 (D) 19/32  I would like to verify this result using integration. I know how to integrate but concept of strip is new to me . can we solve this using only one strip ?


Some thoughts about weighted scoring systems and tweaks to the calculation of scores to provide a more informative ranking order

Just looking at some trends of users and patterns of questions that have been asked, and I thought whether additional badges or weighted systems of scoring can be used for people who contribute very actively but don't get the credit that they probably deserve. For example, I for one think that it is important to ask difficult questions on this forum to help push the thinking in UX design further, yet if you ask a question that people find difficult to answer then it doesn't tend to get up voted as a 'popular' question. One potential solution might be to look at the ranking and reputation of the users that upvote or downvote questions to improve the outcome.  Also, some users generate a large 'momentum' by answering lots of questions, but due to being first to answer and just picking easier questions you can easily mistaken them to be very knowledgeable but in fact you need to dissect the questions and answers more carefully. So perhaps a different sorting or ordering system can be in place (e.g. most recent first) instead of the highest voted first because people will then tend to ignore the rest of the answers.  Lastly, users that have been on the site for a longer period of time benefit from the rankings due to accumulated points over a period of time, so perhaps so decay factor needs to be applied to reflect that they have not contributed actively or recently.


Will Meta Stack Exchange be removed now?

This is a question related to the new .   (Meta Stack Exchange) has various functions: (per the help center)     Meta is for...         ... Stack Exchange users to communicate with each other about the Stack Exchange network (asking questions about how the websites work, or about policies and community decisions)   ... Stack Exchange users to communicate with Stack Overflow, the company (posting bugs, suggesting improvements, or proposing new features), and   ... Stack Overflow, the company, to communicate with the community (soliciting feedback on new ideas or features, or discussing policies that affect the whole network)      Summarizing this, there are these main use cases for Meta:   suggesting new features/improvements to features posting bug reports announcements network-wide policy discussions.   The first three of these use cases seem to be moved off, to another platform:     In early December, we are putting a strategy together for the tools and systems we’ll need. Bug reports, in particular, have been a significant pain point internally and externally! We plan to transition things like bug reports, user and customer support, user feedback, and company announcements off of Meta over the course of next year.   emphasis mine  This leaves the last point, which also seems to be covered by the creation of a moderator advisory board:     we’re putting together a moderator advisory team drawn from our 550 existing moderators (folks who volunteer their time and donate their knowledge and leadership to the community): a small, self-replacing council of moderators who will be tasked with keeping our moderation guidance and methods up-to-date, along with ad-hoc working groups of moderators to work on specific initiatives as needed.   emphasis mine  These changes seem to render Meta Stack Exchange useless.  Do you plan to remove it after doing these changes?  (Note: This doesn't mean I am advocating/agreeing with it. I am just curiously asking)


Is 2 closed questions and 2 (-1) downvoted questions enough for Stack Overflow to no accept questions?

I only have 2 (-1) downvoted questions and 2 closed questions.  Is this enough for Stack Overflow to not accept questions anymore? Because I tried to post a question and it wouldn't let me.  Also, do downvotes on deleted questions still count towards this? Or is it over written into just a deleted question where the downvotes no longer matter?


How to upgrade Ubuntu to specific version?

I am using Ubuntu-14.04 now, and want to upgrade to Ubuntu 16.04.   It will upgrade to the newest Ubuntu-17.10, if I use the commands below:  sudo apt-get update sudo apt-get upgrade sudo apt-get dist-upgrade do-release-upgrade   Does somebody knows "how can I upgrade Ubuntu to certain version (16.04) without re-installing system?  Thanks a lot.


Weird http -> https redirection although not configured

I am running Apache 2.2.15 (CentOS 6.6) with a HTTP-only domain   demo.xml-director.info  Using wget I can retrieve the content properly   wget -S http://demo.xml-director.info --2015-01-05 13:31:41--  http://demo.xml-director.info/ Resolving demo.xml-director.info (demo.xml-director.info)... 176.9.146.28 Connecting to demo.xml-director.info (demo.xml-director.info)|176.9.146.28|:80... connected. HTTP request sent, awaiting response...    HTTP/1.1 200 OK   Date: Mon, 05 Jan 2015 12:31:41 GMT   Server: Zope/(2.13.22, python 2.7.6, linux2) ZServer/1.1   Content-Length: 20227   Expires: Sat, 01 Jan 2000 00:00:00 GMT   Content-Type: text/html;charset=utf-8   X-Ua-Compatible: IE=edge,chrome=1   Content-Language: en   Vary: Accept-Encoding   Keep-Alive: timeout=15, max=100   Connection: Keep-Alive Length: 20227 (20K) [text/html] Saving to: 'index.html.4'   However Chrome/Firefox always change the request from http to https because of HTST. However for this particular domain there is no HSTS configured.  The server runs SSL for www.xml-director.info with enabled HSTS support. However there is further alias here that would map demo.xml-director.info to www.xml-director.info.   How can this problem be resolved.  VHOst for www.xml-director.info:  <VirtualHost *:443>     ServerName www.xml-director.info     ServerAlias xml-director.info      SSLEngine on     SSLCertificateFile /etc/httpd/certs/15742445repl_2.crt     SSLCertificateCHainFile /etc/httpd/certs/15742445repl_2.ca-bundle     SSLCertificateKeyFile /etc/httpd/certs/zopyx.com.key      CustomLog /var/log/httpd/xml-director.info.log combined     DocumentRoot /var/www/xml-director/landing-v1      Header always set Strict-Transport-Security "max-age=63072000; includeSubDomains"      <location "/">         Options +Indexes         Header set Access-Control-Allow-Origin "*"         Header set Access-Control-Allow-Methods "GET,PUT,POST,DELETE"     Header set Access-Control-Allow-Headers "X-Requested-With,Content-Type"     </location>  </VirtualHost>  <VirtualHost *:80>     ServerAlias www.xml-director.com      ServerAlias www.xml-director.info     ServerAlias www.xml-director.de     ServerAlias xml-director.com     ServerAlias xml-director.info     ServerAlias xml-director.de      RedirectPermanent / https://xml-director.info/ </VirtualHost>   and for demo.xml-director.info  <VirtualHost *:80>     ServerName  demo.xml-director.info     RewriteEngine On      RewriteRule ^/(.*) http://127.0.0.1:12020/VirtualHostBase/http/demo.xml-director.info:80/xml-director/VirtualHostRoot/$1 [L,P]     RewriteRule ^/$    http://127.0.0.1:12020/VirtualHostBase/http/demo.xml-director.info:80/xml-director/VirtualHostRoot/$1 [L,P]      CustomLog /var/log/httpd/demo.xml-director.info.log combined     AddOutputFilterByType DEFLATE text/html text/xml text/plain text/css text/javascript      CacheRoot /tmp/cache     CacheEnable disk /     CacheIgnoreCacheControl on      KeepAliveTimeout 15     KeepAlive on      ExpiresActive On     ExpiresByType image/gif "access plus 10 day"     ExpiresByType image/jpg "access plus 10 day"     ExpiresByType image/jpeg "access plus 10 day"     ExpiresByType image/png "access plus 10 day"     ExpiresByType text/javascript "access plus 10 day"     ExpiresByType text/html  "access plus 1 hour"     ExpiresByType text/html  "access plus 1 hour"     ExpiresByType text/css  "access plus 10 days"      <Location "/">         Order allow,deny         Allow from all     </Location>  </VirtualHost>


how to get latex to hyphenate a word that contains a slash?

I'm using 'und/oder' (German for 'and/or') in one of my texts (I know it's not nice :)). Latex separates it 'und/o-der' which is not nice. Using \mbox fixes that problem.  Trying to find a general solution like  \hyphenation{und/oder}   does not work though: 'Improper \hyphenation will be flushed. \hyphenation{und/'.  What would be the correct way to archive this?    Related to , but somewhat different.


Unable to login to my account from GUI interface, 14.04

Unable login to my account from GUI interface, only as Guest. When trying to login, within a few seconds I'm sent back to the login screen. Further, after trying some fixes, when trying login as admin, login screen is not returning back, get only a blank screen and it does not proceed further. Can only Guest login. Login from tty4 terminal is OK.  .xsession-errors contains only these lines:  Can't save user-dirs.dirs Script for ibus started at run_im. Script for auto started at run_im. Script for default started at run_im. init:/home/username/.config/upstart: Unable to load configuration: Permission denied init: dbus pre-start process (4902) terminated with status 1


Do layovers count in the 90-in-180 Schengen rule?

Suppose someone on the 90 of 180 rule leaves Schengen on the 90th day.  Then less than 90 days later, they have a flight with one or more layovers in a Schengen country.  Does it get counted if it's the same plane?  Change of planes?    What if it is overnight but you don't leave the airport?   relates but doesn't specifically mention layovers.  If you don't get off the plane, I presume nobody even looks at your passport.  But in one non-Schengen airport, I had to change planes, but first was required to go through passport control, claim luggage, and re-check the luggage.


How to rewrite this code without using boost?

My task is to modify Sergiu Dotenco's  code to not use boost (not saying boost is bad, but due to some company's policy i have to remove it).   now, Sergiu's WELL is using boost's mpl library, there are quite some logic behind it. So one way is to read up all those, then naturally i would be able to finish the task. The other way is, replacing bit by bit with some best guess.   I'm on the 2nd way to hope this try-and-error approach would be faster. So far I've successfully replaced boost::mpl::if_ and if_c with std::conditional, but hit error when try to update IsPowerOfTwo and Power2Modulo etc, that's why i'm seeking help there.   Below is the code, how to rewrite it without boost, but only c++17?  /**     * Conditional expression of type (r & (r - 1)) == 0 which allows to check     * whether a number @f$r@f$ is of type @f$2^n@f$.     */     typedef boost::mpl::equal_to<         boost::mpl::bitand_<         boost::mpl::_,         boost::mpl::minus<boost::mpl::_, boost::mpl::int_<1>         >         >,         boost::mpl::int_<0>     > IsPowerOfTwo;      template<class UIntType, UIntType r>     struct Power2Modulo     {         typedef typename boost::mpl::apply<             IsPowerOfTwo,             boost::mpl::integral_c<UIntType, r>         >::type type;          BOOST_STATIC_ASSERT(type::value);          template<class T>         static T calc(T value)         {             return value & (r - 1);         }     };   If possible, pls give a short example on how to call it? I tried to instantiate IsPowerOfTwo or Power2Modulo in main with   Detail::IsPowerOfTwo p0;        or  Detail::Power2Modulo<int, 3> p1;   but got compilation error.  I asked a . However, not familiar to metaprogramming and boost, I don't quite get it.


Could this feature be implemented?  I don't see what the point of being able to edit, and being able to see that a question has been edited but not be able to see past edits.   Or is it supposed to work that way and I'm having a bug/being an idiot that's trying to view edit history the wrong way?


How do I get the full path for a file in finder?

I look for a file in finder, finder finds it.  But, I'd like to find it's full path. How do I do that?


How can Moody see through the Invisibility Cloak?

How can Mad-eEye Moody perceive Harry Potter through the Cloak of Invisibility when Xenophilius Lovegood says      "endures eternally, giving constant and impenetrable concealment, no matter what spells are cast at it."?


An indication from convergence of integral

I am reading mathematical analysis of Laplace transform. The author stated that the convergence of the following integral $$\int_{0}^{\infty}f\left(t\right)\mathrm{d}t$$ indicates that for any $\epsilon > 0$ there exists $\tau_0 > 0$ such that $$\left\lvert\int_{\tau}^\infty f\left(t\right)\mathrm{d}t\right\rvert < \epsilon$$ for all $\tau > \tau_{0}$. To me, intuitively it is correct. But how to prove it?


System.out.println("Enter a string: "); String myString = userInput.nextLine();  while (myString != "done") {         System.out.println(myString);         System.out.println("Enter another string: ");         myString = userInput.nextLine();          }    My objective here is to print out all the strings that user inputs until the user types in the string "done". What am I doing wrong?


I am working on a poster in Latex. I found that the integral sign (and also the summation sign) appears to be small. What could make this happen? I never see this in a regular article. I guess it must have something to do with the poster template. I'm using this template:


How do I install 32-bit packages on 64-bit Ubuntu?

I am using the 64-bit version of Ubuntu, but I need to install a 32-bit version of a package to use with a proprietary extension for it, which is only available in 32-bit. How can I install the 32-bit version of the package, while I am running a 64-bit system?


Can a Great Old One warlock use the Awakened Mind feature as a universal translator for Suggestion spells?

start out with a universal translator that works on one target within 30 feet - the  feature (PHB, p. 110):     Starting at 1st level, your alien knowledge gives you the ability to   touch the minds of other creatures. You can communicate telepathically   with any creature you can see within 30 feet of you. You don't need to   share a language with the creature for it to understand your   telepathic utterances, but the creature must be able to understand at   least one language.   This "universal translator" ability appears to be just as powerful as the 3rd level spell "Tongues," and possibly more so in limited situations because it is always on.  A warlock can also get  as a 2nd-level spell:     You suggest a course of activity (limited to a sentence or two) and magically   influence a creature you can see within range that can hear and   understand you.   So it seems to me that a Great Old One warlock who speaks only Common could get within 30 feet of a goblinoid who speaks only Goblin, and communicate telepathically with Awakened Mind while speaking suggestion as a 2nd level spell.  The goblinoid can hear the voice, and the goblinoid can understand the telepathy.  However, I suspect that some DMs would rule that the Warlock must be able to be understood just from the spoken words and not from any additional telepathy.  Does this work? Can a Great Old One warlock use Awakened Mind as a universal translator for Suggestion spells?


How to printf char pointer return from function?

When i run the code i got no output and program crash Anyone know how to correctly print out the char pointer ? #include <stdio.h> char *toUpperCase(char *str) {     int i = 0;     while(str[i] != '\0')     {         str[i] = str[i] - 32;         i++;     }     return str; }  int main() {      printf("%s", toUpperCase("hello"));      return 0; }


Why eclipse creates two class files for Python?

I'm new in Python but loving it.  I'm using Eclipse for IDE, but confused why it creates two classes, Please take a look at screenshot    Can you please tell what it is used for?  Help would be appreciated!


How To Concatenate this Sql Column into Single cell?

ClassName    BookCode First          2 Second         2 Third          2 First          3 Fourth         3 Fifth          3   I want to concatenate this into like this :  ClassName             BookCode First,Second,Third       2 First,Fourth,Fifth       3


True or false: a sequence $\{a_{n}\}$ is convergent if and only if the   subsequences $a_{2n}$ and $c_{2n + 1}$ both converge to the same   number   I think that the answer is true. I know that the converse is true because the subsequences of a convergent sequence always converge to the same number. I'm not sure about the forward direction though. I couldn't come up with a counterexample.


401(k) Contribution When Employer Has No Match?

Long time lurker, first time asker here.  I've seen some similar questions to mine here, but nothing exactly in the same circumstance.  I've seen almost near-consensus that the ordering for investing should be as so:   Fund an employer's 401(k) up until the point that you get the most out of their match. Fund a Roth IRA until you hit the yearly maximum. Fund your 401(k) until you reach that maximum. If you have further cash to invest, you have to put it in an account that is not tax-sheltered.   Right now, I'm contributing 10% of my paycheck to the company-sponsored 401(k), but the company does not offer any sort of match right now, but it is planned to resume in the near-future.  Given that there is no match, I was wondering if it would be a better idea suspend or reduce the amount I'm contributing to the 401(k) and move that into another investment vehicle, like a Roth IRA.  I also have the option in my 401(k) plan to put a portion of my money in a Roth 401(k).  I'm currently 22 and have no major debts --just daily expenses put on a credit card, which is always paid off at the end of the month.  I'm in the US.


How to overcome error "look-behind requires fixed-width pattern" in Python?

Could anyone tell me why this is not working in Python?  s = "conversion of hotel into 16no managed flats" re.sub("((?<=\d\w|\w\d)|(?<=\d))(\s*NO\.|NO\s)", " no ", s, re.IGNORECASE)   It's working in https://regex101.com/ with Python engine selected.  I've overcame the look-behind fix length issue but not quite.


Can LibreOffice Writer read Microsoft Documents?

I'm just wondering.Because I don't know if there are some things you can do in LireOffice Writer but you cannot do in Microsoft Word.Because my son does a lot of computer projects and I installed Ubuntu on VirtualBox so he can use it and install Dropbox on it to transfer a document on to my Windows 7 computer (The computer that I used to install it Ubuntu on a virtual machine) and keep working on both machines.


Why didn't (or did) I or some other user get a hat although the requirements were (or weren't) fulfilled?

During Winter Bash, users can earn hats. But sometimes it seems that a hat was awarded even though its requirements weren't (yet) met, or vice versa.  What could be the reason for this?


The folder size of folder Logs\CBS is increasing forever

My disk driver on my computer is increasing unexpectedly. I have to reset my computer but it didn't resolve the issue. After my inspection, I found the folder C:\Windows\Logs\CBS is too big.  I tried to delete them manually but I got this error   I believe the issue comes from Window Update so I disable it from Administrator Tool/Service.  But again, the issue was resolved. The file's size is still bigger and bigger. You can see the file size now is now 47Gb. (before it was 41Gb)    Anyone also faced this issue and know how to fix it can help me?  Thank you.  UPDATE 1: I used Process Explorer () to find and kill the process TiWorker.exe but I didn't success


Identifiability of a state space model (Dynamic Linear Model)

Take a general linear Gaussian state space model (SSM)(aka Dynamic Linear Model DLM):    \begin{align} X_{t+1} &= FX_t + V_t  \\   Y &= HX_t+W_t  \\[10pt]   V_t &\sim N(0,Q)  \\   W_t &\sim N(0,R)  \\ \end{align}  I am interested in the unidentifiability issues related to these models:   Hamilton (1994) states that ”in the absence of restrictions on F, H, Q and R, the parameters of the state-space representation are unidentified - more than one set of values for the parameters can give rise to the identical value of the likelihood function, and the data give us no guide for choosing among these”  Now I realise that this representation is not unique as multiplication by any orthonormal matrix $M$ produces a new representation:  \begin{align} MX_{t+1} &= MFM^{-1}M X_t + MV_t  \\   Y        &= HM^{-1}MX_t+W_t   \end{align}  This type of unidentifiability where the observed values can be produced by various orthonormal transformations of the state variables is inherent to state space models.  However, I also came across another type of unidentifiability that seems to be related to the estimation method. In this case "Kalman Filtering." See the simple example starting on page 8 of .  In this case there is a linear transformation of the observation equation and an offsetting one made to the variance of the state equation     Do both the transformations above give rise to the same kind of identifiability issues described by Hamilton (I believe they do but want to check)? Are there other ways in which identifiability issues can manifest themselves in Linear Gaussian SSMs? Is the fix always the same find constraints or analogously (Bayesian priors) that will ensure that the final parameters are correct?   Lastly  in Matlab suggests that it is possible to build an "identifiable SSM". Unfortunately the link doesn't explain the theory. Thus:   It is possible to translate any Linear Gaussian SSM into an "identifiable form"? Can someone please supply a link reference explaining how this works. It would seem at first blush that no matter what representation is used initially it would still be subject to the problems shown above?


How to use apostrophe with plural object of preposition

Which apostrophe is correct? (There are multiple dogs.)  One of the dogs' tails One of the dog's tails  I believe it is the former but I'm not 100% certain. I found absolutely no guidance on this when I searched on the internet.


Blender Python - How to activate selected objects?

Im writing a script to automate a few tasks in blender. The script performs the following tasks: 1st set of similar objects  creates a new material puts the new material in the 1st material slot Rename a batch of the same objects Unwraps the objects  2nd set of similar objects  repeats the 4 tasks described above  The only thing im having trouble with figuring out is the transisition from 1st set of objects to the 2nd. I have included some of the code below: for obj in bpy.context.selected_objects:     obj.select_set(False)      bpy.data.objects["Window Panel"].select_set(True)  so = bpy.context.active_object  so.material_slots[0].material = bpy.data.materials.new(name = "WindowPanel") bpy.context.object.active_material.use_nodes = True  bpy.data.objects["Window Panel"].select_set(False)  The purpose of the first two lines of code is to deselect all the objects, to prepare for a new set of objects. However, the problem is that when i run the script, the former selected object is still the active object... So my question is how it is possible to "unactivate" the former object or "active" the newly selected objects? To clarify my question, i have included the following picture showing my problem: As shown, the former object is still the active one, which is messing up my script..  Help would be much appreciated :-)!


How to copy files that have too long of a filepath in Windows?

I need to make backups of some files on a network share. However, I need to copy those files to my local drive before burning the disks because those files might be in use. Some of the files won't copy because the file path is too long. Is there any workaround other than changing the file structure?


Do the comment boxes no-longer auto-focus?

Is it just me, or does the comment input field no longer automatically gain focus when I hit "add comment"? I never realised I used it, but now that it's gone it's really annoying me!  Firefox 25.0.1 on Windows XP SP3


I would like to flatten a terrain mesh I generated using a racetrack mesh so the terrain appears flatter around the area where the track runs through, I've tried a few different modifiers for this and the closest one to what I needed was the cast modifier, unfortunately it only deforms with the 3 primitive shapes around the transform of the track and not the mesh itself. Is there a plausible way of doing this or would I have to sculpt the terrain manually? The red circles in the picture below illustrate where I'd need the terrain to flatten out for the track to run through. Thanks in advance.


Let $S= \{ 1,2,\ldots,n \}$. and $V$ be the set of all functions $f: S \to \mathbb{R}$. $V$ is a vector space defined by: $$(f+ g)(x) = f(x) + g(x) \text{ and } (cf)(x)=cf(x). $$ Find a basis for $V$ and $\dim V$.  I'm not sure how to answer this question, it seems different than how I learned solving a basis, which was through a set of vectors, anyone know how I can tackle this?


I am trying to plot the elliptic curve secp256k1 y^2=x^3+7 in my latex-document.  \begin{center} \begin{tikzpicture}[domain=-4:4, samples at ={-1.769292354238631, -1.76, -1.74, ..., 2.26, 2.35, 2.7, 2.9}]     \draw[->] (-2.2,0) -- (3.2,0) node[right] {$x$};     \draw[->] (0,-2.2) -- (0,4.2) node[above] {$y$};     \draw[->, color=red] plot (\x,{sqrt(\x^3+7)}) node[right] {$y^2=x^3-2x+2$};     \draw[->, color=red] plot (\x,{-sqrt(\x^3+7)}) node[right] {} \end{tikzpicture} \end{center}   but this gives me a curve that is interrupted at the left. And to be honest, I don't really know what all of these comments mean.  I would be happy if someone could help me, or has a good tutorial that explains how the plotting in Latex works!  Thanks in advance! And all the best.


Trying to get unetbootin to write a Windows ISO on latest version of Ubuntu

I downloaded a Windows ISO file, and I want to install it on a USB flash drive through Ubuntu. However I can't seem to get unetbootin to pop up. I've tried everything. I also tried using another program and got it to write it to the USB, however it took 12 hours for a 3gb file? When I finally rebooted, and selected load from flash drive, it would just start loading up Ubuntu again.   I just want a copy of Windows on my new computer, but I need to either get unetbootin to work, or else get an alternative to work.


Why does $\int\limits_0^1 {\dfrac{{x - 1}}{{\ln x}}} \;\text{d}x=\ln2$?

I have found that  $$\int\limits_0^1 {\dfrac{{x - 1}}{{\ln x}}} \;\text{d}x=\ln2$$  but I can't prove it. Any hint?  Thank you in advance


I have included a template function declaration in a header file and the defintion of the function is written in the .cpp file

I have declared a template function in .h file and defined in a .cpp file and calling the function from another .cpp file.  i am getting the following error  /tmp/ccJg5vwy.o: In function main': main.cpp:(.text+0x8f): undefined reference toshort temp < int, std::allocator < int > >(std::__cxx11::list > const&)'   collect2: error: ld returned 1 exit status  my files are:  //main.cpp  #include"a.h" #include<iostream> #include<list> using namespace std;  int main(){     list<int> arr(5);     for (int i=0;i<5;i++)         arr.push_back(i);     fun1();     fun2();     temp(arr);     return 0; }   //a.h  #include <list> using namespace std; void fun1(); void fun2(); template <class L ,class A>     short temp(const list<L,A>& val);   //fun2.cpp  #include"a.h" #include<iostream> using namespace std; void fun2(){     cout<<"I am in function2\n"; }   //a.cpp  #include "a.h" #include<iostream> using namespace std; void fun1() {         cout<<"I am in function1\n"; } template <class L,class A>     short temp(const list<L,A>& val){         cout<<"inside the template function\n";         typename list<L,A>::const_iterator iter=val.begin();          while (iter != val.end())                 {                        cout<< *iter << endl;                        ++iter;                 }          cout<<"leaving the template function\n";             return 0;     }   and i am compiling the files in the following format  g++ a.cpp fun2.cpp main.cpp  I am not getting why there is a linking problem.  I have also tried by changing a.cpp and a.h to the following format but still i am getting the error  //a.cpp  #include "a.h" #include<iostream> using namespace std; void fun1() {     cout<<"I am in function1\n"; } template <class L>     short temp(const list<L>& val){         cout<<"inside the template function\n";         typename list<L>::const_iterator iter=val.begin();         while (iter != val.end())                 {                        cout<< *iter << endl;                        ++iter;                 }          cout<<"leaving the template function\n";             return 0;     }      //a.h  #include <list> using namespace std; void fun1(); void fun2(); template <class L> short temp(const list<L>& val);   in this case error is  /tmp/cce0eJj9.o: In function main': main.cpp:(.text+0x8f): undefined reference toshort temp< int >(std::__cxx11::list > const&)' collect2: error: ld returned 1 exit status


In The Undiscovered Country, the Klingons view Shakespeare as one of their own and the Earth versions as adaptations. How on Earth could that be? Shakespeare was certainly human as forehead ridges would have been noticed even in that period of history.  Is this some cosmic coincidence with similar works by two different writers or did the Klingons like the work so much they retconned him as one of their writers?


So I made a shell script. I want to be able to open it as if it were an application (i.e: Hit super, type the script's name, hit enter, be happy). At this point it just displays the file in gedit. How do I make it auto run?  edit: To clarify. I have made the script executable. When I click it in nemo, it gives a little prompt asking me to run it, and it runs as expected.


German sci-fi tv show with minimalist music, 70's or 80's?

Some years ago, if I remember correctly, I was looking for sci-fi TV shows on Youtube, so I caught some snippets/inserts on Youtube, which were apparently from a German sci-fi TV show. It had rather minimalistic/noisy music, and there was a sort of a brutalist architecture vibe in the show. Unfortunately, I'm not a German speaker, so I didn't understand the story, nor did I remember the title. But as far as I can remember, it was in color, and the fashion/graininess of picture suggested it was from the late 70s or early 80s (so it would have been either East or West German production).  So now when I look for German sci-fi TV shows, all I can find are shows like "Alpha Alpha" (                               -> similar picture quality to what I remember, so probably close in period, but way too funky music in this trailer), or "Alpha 0.7 - Der Feind in dir" (that one is way too new).  I'm guessing the show was sci-fi due to some unseen computers or something (or maybe time travel), as there were no obvious "future technologies" (such as  lasers, holograms, or even computers), I think the architecture and interior design was (and the minimalist electronic music) was what mostly gave the association of "future" in that show.  I am aware this is quite vague description, but if anyone recognizes anything from this description, I'd love to hear a hint!  EDIT: I also remember the clothing was basically "normal" from the period, nothing (extremely) sci-fi-ish...


I was young when Bioshock 1 came out and did not have a PC strong enough to play it. Over the past years I forgot about it but saw other Bioshock titles coming out but I never had a closer look at it.   Now I'm thinking about playing them but I don't know where to start... Is it necessary to play all the Bioshock games through to understand the story or can I just start with Bioshock Infinite? Is the story even connected in all the games?  Please no spoilers :*


What is the grammar rule here? How do I explain this in a simple way?

So my Japanese friend asked me why we can say   Is he gone?  Is he finished?   But we can't say   Is he changed?  Is he arrived?  Is he fallen?  Is he shrunk?  Is he departed?  Is he died?  Is he melted?   I'm wondering what the grammar here is. changed, fallen, departed can be used as adjectives so shouldn't it be okay to use it in that kind of sentence? But I feel a entence like "Is he fallen?" sounds unnatural.   How do I go about explaining this in an easy-to-understand way to my Japanese friend?   I appreciate any help! Thank you.


Show the following continuous function has a solution $f(c) = 0$

Let $S = [0,1] \times [0,1]$, and let $f: S \rightarrow \mathbb{R}$ be continuous. Assume for each $a \in S$, there exists a $b \in S$ such that $|f(b)| \leq \frac{1}{2}|f(a)|$. Show that there exists a point $c \in S$ such that $f(c) = 0$. My idea is to use the intermediate value theorem. So let $a \in S$. Then, there exists $b \in S$ such that $|f(b)| \leq \frac{1}{2}|f(a)|$. If $f(a) = 0$ or $f(b) = 0$, then we're done. So assume $f(a) \neq 0$ and $f(b) \neq 0$. Then, from $|f(b)| \leq \frac{1}{2}|f(a)|$, we have $-\frac{1}{2}|f(a)| \leq f(b) \leq \frac{1}{2}|f(a)|$. But I don't see how I can apply IVT from here since we are not guaranteed that $\pm \frac{1}{2}|f(a)|$ is in the range of $f$. Perhaps $f$ maps $S$ to only positive reals.


Does my B1/B2 Visa for the US permit me to travel there from anywhere, or just my home country?

I am an Indian with a valid B1\B2 visa, currently residing in Sweden. Can I travel to the US from Sweden or do I have to go through India?


Should a retrieval method return 'null' or throw an exception when it can't produce the return value?

I am using java language,I have a method that is supposed to return an object if it is found. If it is not found, should I:  return null throw an exception other  Which is the best practise or idiom?


Explanation of charge for a student just entering physics

I am trying to understand charge what it is actually and how electrons have negative charge like suppose I assume that scientist assume protons have something because of which they behave like that (attract other electrons and repel other protons)  but what do they mean by electron have negative of that thing.how can something have negative of a thing.


On the size of rational numbers and Irrational numbers.

Being a high school student, It's obvious to me that there are both an infinite number of rational and irrational numbers. However I don't really see if there is more rational than irrational, irrational than rational, or if they are of the same percentage of the reals. All I know is between two rationals there is a irrational, and between two irrational a there is a rational, along with my experience that I usually work more with rationals. How would we calculate the percentage of irrationals and the percentage of rationals to the reals. And how could some infinities be larger than others, doesn't seem to make sense to me.


In Evince, don't see the option to add an annotation

I'm trying to follow the instructions on  to add annotations to a PDF document in Evince. However, I don't see separate "List" and "Add" tabs as in the documentation. This is what I see:    Do I perhaps have to install a plug-in to enable annotation?


I'm currently studying Cayley-Hamilton proof, but I think I'm missing something massive. The theorem states that an endomorphism $\phi$ cancels its characteristic polynomial. I don't understand why the proof is not trivial. Let $A$ be a matrix of $\phi$ in a basis $\mathcal{B}$. We know that the characteristic polynomial of $A$ is the same as $\phi$ no matter which basis of the vector space we take. Then, $$P_A(A)=\det(A-AI)=\det(A-A)=0$$ So the proof should be trivial, I don't understand where my error is.


How can I find out when Windows was last started?

systeminfo shows when the system came up after a restart, but does not show when it comes up after a shutdown and then a power on.  For instance when I run this command:  systeminfo | find "Sys"   the output shows:  System Boot Time:          8/10/2018, 8:45:22 AM   Which was when I did a restart.  I tried a solution in the previous question:  Get-WinEvent -LogName Microsoft-Windows-Diagnostics-Performance/Operational | Where { $_.Id -eq 200 }  and got these results on my laptop:   PS C:\Program Files\PowerShell\6.0.0> Get-WinEvent -LogName Microsoft-Windows-Diagnostics-Performance/Operational | Wher e { $_.Id -eq 200 }      ProviderName: Microsoft-Windows-Diagnostics-Performance  TimeCreated                     Id LevelDisplayName Message -----------                     -- ---------------- ------- 7/30/2018 1:54:18 PM           200 Critical         Windows has shutdown: ... 6/29/2018 9:08:40 AM           200 Critical         Windows has shutdown: ...   PS C:\Program Files\PowerShell\6.0.0>    I'm looking for the time I turn on the computer and the time I shut it down each day. I'd like a command line so I can collect the information into a batch file.


Autosave comment as a draft or display some warning upon leaving the page

This has happened to me a few times: I start writing a comment, then close the tab or follow some links without having finished to write the comment, thereby losing my draft. Sometimes my browser decides to crash too, or I need to leave before having the time to finish writing the comment.  How about autosaving comments as drafts or display some warning upon leaving the page as we do for ?


I am trying to find an efficient way of evaluating the gamma function gamma(t) where t is a complex number.  The Wolfram Mathworld page  gives a number of formulas involving infinite series and infinite products, but it does not appear to have any information on rates of convergence.


How can I lock a folder so that it CANNOT be erased?

On my computer running Windows XP Pro SP3 I have a folder on my desktop that is very important. How can I lock it so that I can alter anything in it, but the folder itself cannot be removed without resetting a (lock/unlock?) switch?


Is it possible to make raid 0 from 2 ssd drives?

Like in the title, is it possible. I was thinking about that last year but everybody told me that it's not possible due to controller issues. Today I revisited that idea after seeing awesome vids on youtube running two ssd in raid 0. I'm running 2xhdd in raid 0 and I'm wondering wether to change 2x64gb sdd raid 0 for system and 2xhdd for files.


How to add printer using SAMBA in ubuntu 13.04?

The option is not present anymore in system settings printer to add:  Windows Printer via SAMBA


PHP MySQLi Database Class and foreign characters

I am using joshcam/ PHP MySQLi class and currently having problem on inserting foreign character in the table.  I tried to update using rawQuery to identify if the problem lies with the class itself.  $db->rawQuery("UPDATE table SET fieldname=''龙岗区中心" WHERE . ..... ");  The query executes with no problem but it saves as ?????? in the table.  If i use mysql_query update on the same table , the characters insert in the table with no problem.  Has anyone experienced this? The charset is set as UTF-8.  Any help would be much appreciated.  Regards  Ash


init program doesn't work, can't boot the system

Today I opened my Ubuntu and I saw    What should I do ?


How to do SEO for dynamically user generated content?

I've read tens of SEO guides and none of them seem to talk about this kind of stuff, I understand that if I have a static website like a blog, I got to pay attention to keywords, title, relevancy all that.   But, what if my website uses dynamic content with query parameters, and all that content is generated from the back-end, like here on stack for example, you go to "question" and then ther's a query string that pulls the data.  Can pages like that be crawled, because they don't really exist.  Every guide I've found seems to talk about static websites, I understand that all that is applicable too but, is there some other steps you need to do for dynamic content that affects SEO?


If $p$ and $q$ are distinct primes such that $p|c$ and $q|c$, prove that $pq|c$ ..  I start with this:   if $c=pk$  and $c=qt$ then $q|pk$ and $p|qt$  but a couldn't get the solution.  I need your help


Does time dilation mean that faster than light travel is backwards time travel?

Ok. So my question is, I've always heard it that Faster Than Light travel is supposedly backwards time travel.  However, the time dilation formula is  $$T=\frac{T_0}{\sqrt{1-v^2/c^2}}$$  And while it is true that speeds greater than $c$ turn the denominator negative, doesn't the whole thing get rendered a complex fraction, rather than negative or backwards time flow, due to the square root of a negative number being a complex one?  Wouldn't this then mean that faster than light travel does something weird, rather than backwards time travel? In other words, wouldn't what happens during faster than light travel be some sort travel in a complex plane and wouldn't that have radically different implications to backwards time travel, depending on the direction one took FTL?


How does cooling a magnet allow it to quantum lock/levitate? I have seen it in videos but do not know how it works.


I am making some photo-realistic rocks in Cycles, and I made a material using nodes, and combined two images using a bunch of modifiers and then connected them to the rocks material node. How can I take the rocks material and save it as an image? I've tried to bake it, but I can never find where the baked image is. Thanks in advance.


I've been having the hardest time photographing objects that are encrusted in rhinestones and capturing their sparkle.  My understanding of sparkle is that it comes from two components: the dynamic range of our eyes and movement of our heads. Screens don't do a good job of reproducing the dynamic range that our eyes can see and still photos don't do a good job of reproducing movement.  I've looked at various other answers on this site, but I'm still left wanting a truly "sparkly" picture. I've tried:    (black acrylic did a pretty good job for this. It shows a reflection of the object, but effectively dimmed by a number of stops, so the bits that sparkle are still bright) Using a video of the object slowly moving, instead of still photos. This is probably the best option so far, but as one might imagine it's not always a usable option. Using a number of bright point light sources (e.g. non-diffused LEDs, xmas lights). , such as a flashlight/torch or non-diffused halogen lamp Long exposures, short exposures; narrow apertures, wide ones.   No matter what I do, I get more diffuse light (which is good for giving the overall appearance of the object), but very little sparkle. I understand that sparkle is small, bright points of light shining back at the camera, from the mirrored surface of the rhinestone facets, but somehow it never seems enough when captured by the camera.  Perhaps the real question is: how do you show sparkle on a low dynamic-range display? How do you capture it and if it's not easy to capture, is there a way to convince your eye to see something as sparkly?  Here's an example of a shot that I've been trying to make more sparkly:   (artwork by Judith Klausner, photo by myself)  The above photo was lit by a single halogen bulb above the camera and a flash pointed directly at it off to the right and above the camera. It was taken within a diffusion box with the front entirely open and black velvet on the left / back side, and black acrylic underneath it all. 90mm manual prime macro lens on a D600 at F16 with a 1.3" exposure.


How to get rid of my spamming notification?

The DivX player has installed a junk notification on my Mac saying:     A new version of DivX is available.   as shown below:    This stupid notification bumps up every hour or so, and there is no way to turn it off (there's no disable option when I click on it's icon). I don't want and don't need their software. I can't see the player in my Notification panel.    Question: How to prevent DivX from spamming me with notifications?


I have the following code to test the conversion from double to long:  double dVal = (double)(long.MaxValue);  // 9.2233720368547758E+18; if (dVal <= long.MaxValue && dVal >= long.MinValue) {   long lVal1 = (long)(dVal);           // gives -9223372036854775808 !!!   Console.WriteLine($"lVal1 = {lVal1}");   long lVal2 = Convert.ToInt64(dVal);  // gives System.OverflowException }   I expected lVal1/2 to be 9223372036854775807 or 9223372036854775800 because of the truncation or rounding in the double type.  How can I convert double to long correctly for all cases? Is there something in the framework already or do I need to implement it?


I have recently installed a Ubuntu dual-boot with Windows on my PC (still trying to get the Windows part working). The internet on Ubuntu is really slow compared to Windows.   A sppedtest.net test has a ping of 1000ms+ and won't even run.  It's taken me around 10 minutes to download 4000 kB Pinging 8.8.8.8 (Google DNS anycast) returns times of 1500ms when it should be < 20 ms   I have a feeling this could be down to the Ubunutu installation. My Mac (right next to the Ubuntu PC) is working fine and does a Speedtest.net test with a ping of 9ms, 36mpbs download and 10mpbs upload.  What could be the problem?


Handle FTP client.DownloadString file not found exception

How can I check if the file exists in my FTP server? I am getting an catch exception because sometimes the file does not exists.   DateTime now = DateTime.Now;             string repotroday = "report_" + now.Year.ToString() + "_" + now.Month.ToString() + "_" + now.Day.ToString() + ".csv";              WebClient client = new WebClient();             string url = "ftp://vps.myserver.com/" + repotroday;             client.Credentials = new NetworkCredential("SURE", "iRent@123");             string contents = client.DownloadString(url);   However, when I do not have the report in the FTP, it returns: The remote server returned an error: (550) File unavailable (e.g., file not found, no access)  Is there a way to check if the file exists before trying to download it?  Thanks


Simple code breaks when calling it from a function

I have this code: secret_word = "secretword" guess = ""  def askForGuess():     guess = input("Introduce the secret word :")     print(guess,secret_word)       while guess != secret_word:     askForGuess()         print("You've won!")   If I call askForGuess() inside the while statement it will never print 'You've won!' not even if I introduce the secret word correctly. However, if I just simply paste askForGuess() code inside of the while statement it works. Does anyone know why?


Is the value for the speed of light in vacuum irrelevant?

Does it matter that the speed of light, $c$, is 299,792,458 meters per second in a vacuum? Would the universe be different if $c$ were, for example, 1 meter per second? Or should things be the same, whatever $c$'s value is?


I'm aware that actual focal length of a lens on APS-C cameras is longer than what is written on the lens.   My question is, for lenses that are specially designed for APS-C cameras (like a Nikkor DX lens), do they write actual focal length on the lens or it is the focal length if mounted on a full-frame camera?


How to typeset some text including math content in sans serif

I have a blurb of text in an external macro  \SomeText, which I want to typeset in sans serif. However, \sffamily\SomeText does not change the math font and \sffamily\mathsf{\SomeText} does not work, as I am not in math mode.  So how can I typeset material in sans serif, whether it does or does not include math stuff?  \documentclass{article} \usepackage{lmodern}  \newcommand{\SomeText}{This is some ($words \geq 5$) Text with math stuff in it: $a^2+b^2=c^2$}  \begin{document}   \begin{description}     \item[Roman:] \SomeText     \item[Sans:] {\sffamily \SomeText \\ (however, the math is still Roman)}  %    LaTeX Error: \mathsf allowed only in math mode %    \item[AllSans:] {\sffamily\mathsf \SomeText}   \end{description} \end{document}


How can I upload a pygame that I made on a website?

I'm a beginner programmer and I want to know how can you upload your pygame on websites like coolmathgames or any game websites, do you upload your code after you get a deal with them? do you save it into a file and then upload it through some button? Like how does the whole thing work. Thanks!


How to view TeXnicCenter PDF output with Adobe Acrobat and Adobe Reader?

I want to view the PDF output from TeXnicCenter with the latest version of Adobe Acrobat or Adobe Reader. How do I configure TeXnicCenter accordingly?


How to build a model with a continuous response variable bounded from 0 to 1?

How to build a regression model with a continuous response variable bounded from 0 to 1?   I think it is not logistic regression, where I am not predicting a binary response variable, Right?  Sorry for duplication if any, I tried to search but not find. (I feel this question must be asked many times.)


sed command to replace a string from one file with entire contents of another file

I want to write a sed (or awk) command to replace a string from one file with the entire contents of another file. Note that second file from which I want to get the content has more than one line. I tried this:  sed -e "s/PLACEHOLDER/$(sed 's:/:\\/:g' TestOutput.txt)/" SQLInput.txt   but got an error saying sed: -e expression #1, char 22: unterminated 's' command


I have Install Ubuntu 18.04.Battery is draining very quickly approx 1:30 hr only. while in window same laptop have upto 4:50 hr battery. I have Lenovo Ideapad 310 (i5 6th gen).


Not finitely generated ideal but only contained in finitely generated ideals implies ideal is prime

I would like to prove the following.     Let $\mathfrak{a}$ be an ideal in a commutative ring, $R$, with the property that $\mathfrak{a}$ is not finitely generated but every ideal properly containing $\mathfrak{a}$ is finitely generated then in fact $\mathfrak{a}$ is a prime ideal.   My idea is to try contradiction.   So suppose there are $a,b\in R$ with $ab\in \mathfrak{a}$ but $a, b\notin \mathfrak{a}$. Then $(a)+\mathfrak{a}$ and $(b)+\mathfrak{a}$ are ideals that properly contain $\mathfrak{a}$ and so they are finitely generated. However, at this point I'm not really sure what I should do next.  Thanks for any help!


Let's say a creature with infect attacks and the opponent blocks with a creature that has first strike. How does the combat resolve? Does the blocking creature with first strike still get the -1/-1 counter?


For which $n≥2$ does there exist $\sigma\in A_n$ with $|\sigma| > n$? I have a proof that I'd like to be verified. My proof that there exists $\sigma\in A_n$ with $|\sigma| > n$ if and only if $n\geq 8$: For $n<8$, one can manually verify for each $n$ that there is no $\sigma\in A_n$ with order greater than $n$. Suppose $n\geq 8$. Case 1: $n$ is even and $3\not\mid n$. Then the permutation $(1,2,3)(4,\dots,n)$ is even and has order $\operatorname{lcm}(3,n-3)=3n-9\geq n+16-9\geq n + 7$. Case 2: $n$ is even and $3\mid n$. Then $n\geq 12$, so $n-2\geq 8$ is even and is not divisible by 3. Applying Case 1, we see that $(1,2,3)(4,\dots,n-2)\in A_n$ has order at least $n+5$. Case 3: $n$ is odd. Then apply one of the previous two cases with $n-1$ to get an even permutation with order at least $n+4$. $\blacksquare$ Is my proof correct? It doesn't seem very elegant. Is there some slicker proof?


Why are backslashes displayed as "₩" (Korean won sign, “W”+strikethrough) in Notepad++?

I have scoured the internet for over 2 hours trying to find a solution that works to resolve this.  I am trying to do a space escape in a .css file in Notepad++ and it just keeps showing this weird W thing (which I found out is the Korean currency symbol for "Won").  I've attempted all of the obvious and suggested fixes I was able to find - reinstalled Notepad++, changed the language settings, etc.  It only does this in CSS files and it only does it in Notepad++.  Another odd thing is that "Find"(Cntrl+F) results for "\" show this as the only instance in the file.    I want it to display  #status.En\ panne{...}   My two questions are: 1) Is there a way to resolve this?  2) Will just leaving it there still act as a space escape?


Get li value from ul filled by JavaScript

I have filled some "ul"s directly in HTML e.g.  <button class="btn btn-primary dropdown-toggle" type="button" data-toggle="dropdown">Kennzahl     </button>

volume

netSentiment

authors

   and had no trouble reading the selected value by   $('#measure li').on('click', function(){     $(this).text(); });   Then I have tried to get the chosen Value from a "ul" that I filled by JavaScript:  Something like  $('#projectId').append('
' + projects[i].name + '
');   The Select is filled with the "li"s. But when I select one, the result isn't caught by the same JavaScript I could use with the "li" directly filled in HTML.