Currently Studying "Linear Algebra" by Georgi E. Shilov. I encountered the following problem. Prove that: $$\begin{vmatrix} 1 & 1 & ... & 1\\ x_1 & x_2 & ... & x_n\\ {x_1}^2 & {x_2}^2 & ... & {x_n}^2\\ . & . & ... & .\\ {x_1}^{n-2} & {x_2}^{n-2} & ... & {x_n}^{n-2}\\ {x_1}^{n} & {x_2}^{n} & ... & {x_n}^{n} \end{vmatrix} =  \begin{vmatrix} 1 & 1 & ... & 1\\ x_1 & x_2 & ... & x_n\\ {x_1}^2 & {x_2}^2 & ... & {x_n}^2\\ . & . & ... & .\\ {x_1}^{n-2} & {x_2}^{n-2} & ... & {x_n}^{n-2}\\ {x_1}^{n-1} & {x_2}^{n-1} & ... & {x_n}^{n-1} \end{vmatrix} * \sum_{k=1}^n x_k$$ Immediately I noticed that the matrix on the right is the vandermonde matrix. The first thing I did was to try to find a column or row on the left side matrix to try to do a cofactor expansion that will lead to minors equal to the vandermonde. Unfortunatelly I dont think thats the aproach. Another thing that jumped in is that it has to be related to the row with powers of n-1 since its the biggest difference between them. I hope someone can guide me in the right direction.


We know that we have now 50/60Hz in our walls due to mainly historical reasons - back 100 years ago there were no ways to up/down scale DC voltage.  These days we just have problems due to that - every single device sold have to have ~1uF cap per 1W of power before it's PSU to have enough power when we go through 0. (this problem does not exist in 3-phase power, but it available mainly in industrial applications only AFAIK) + caps have to have higher rated voltage to survive sine peaks + all this PFC mess.  Is that correct to say that if we were to design modern power grid, we would skip AC, and just have DC everywhere? As far as I see, it would significantly increase reliability & reduce cost of many devices out there.


Does $f(x)$ converge when $x$ goes to infinity if $f'(x)$ goes to $0$ when $x$ goes to infinity?

Clarification: Does $\lim\limits_{x \to \infty}f'(x)=0$ as $x$ approaches infinity  mean $\lim\limits_{x \to \infty} f(x)$ exists in the extended real numbers $[-\infty,\infty]$?  I was thinking a lot about this problem and I couldn't  prove it; I would appreciate any help!  This isn't a duplicate! In that problem you have to prove that the limit of f(x) exists in the extended real numbers, you don't assume it does.


#!/bin/bash -x or -v doesn't print to stdout on Ubuntu 20.04

I'm doing one of the courses on bash, which seems a bit outdated.I have a  simple script below, which should allow me to see lines as they are read or executed, but my console gives nothing back. The $1 argument passed to bartek_report.sh is missing on purpose as I wanted to see what happens when the console hangs. Using the latest Ubuntu. #!/bin/bash -v    #or -x     # creates a report for a single container  # exercise: add a variable called 'directory' # that determines where we save our output file  directory="reports"  mkdir -p $directory grep $1 shipments.csv > $directory/$1.csv echo Report created in $directory under filename $1.csv  When I call the script under bash it just hangs like without -x or -v, why? bartek@Lenovo-LAB~/Desktop/Devs/bash_learning/02/demos/after_m2$ sh bartek_report.sh [blinking cursor]


Difference between a HashMap and a dictionary ADT

What is the difference between a Hash Map and dictionary ADT. And when to prefer one over another. For my programming assignment my instructor has asked to use one of them but I don't see any difference in between both. The program is supposed to work with a huge no. of strings. Any suggestions?


Inequality proof by induction, what to do next in the step

I have to prove that for $n = 1, 2...$ it holds: $2\sqrt{n+1} - 2 < 1 + \frac{1}{\sqrt2} + \frac{1}{\sqrt3} + ... + \frac{1}{\sqrt{n}}$  Base: For $n = 1$ holds, because $2\sqrt{2}-2 < 1$  Step: assume holds for $n_0$.  $2\sqrt{n+2} - 2 < 1 + \frac{1}{\sqrt2} + \frac{1}{\sqrt3} + ... + \frac{1}{\sqrt{n + 1}}$. But I do not know what to do next? How this can be proved?


Consider the fraction $1+\frac{2}{3+\frac{4}{5+\frac{6}{7+\frac{8}{9+\frac{10}{11+\frac{12}{13+...}}}}}}$. This fraction approaches about $1.54$ as you continue it. My question is simple. Does anyone have any idea why this converges to this specific number?   I’ve tried algebraically messing with it, (saying that “$x=1+\frac{2}{3+\frac{4}{5+...}}$” then seeing where it goes.) but to no avail.  I tried to cut off the fraction at different points to try to find patterns in the fractions,( Like cutting off at 7 and solving $1+\frac{2}{3+\frac{4}{5+\frac{6}{7}}}$) but that didn’t work either.  I cannot seem to express it in terms of anything else, either.


Does running a Minecraft server run with less lag on Ubuntu server than on Windows 7?

I run windows 7. I run a Minecraft server, but I can only host around 9 players before lag appears.   I heard that Ubuntu can run a server with much better performance than Windows 7. I kind of like the whole idea of Ubuntu, but I don't want to change my OS to Unix or anything else.  Basically, my question is, does running a server (specifically and Minecraft server) run easier and faster on a Ubuntu server? On top of that, how would one set that up?


Power Analysis for Logistic Regression with one nominal variable

How do I estimate sample size or do power analysis for logistic regression with one nominal independent variable? Is there a way to do it with Stata?


Java 8 Stream sort map of string to list based on list

I have a map with key as string and value as list of strings  I want to sort the map based on the list of strings(Lexicographically).  If I have a List<List<String>> then I can sort by  List<List<String>> sortedlist = new LinkedList<>(); sortedlist.sort((l1, l2) -> l1.get(0).compareTo(l2.get(0)));   But I have a Map<String, List<String>> sortedMap and I want to sort this based on the values, i.e. first element of each list within the value set of the map.  I am trying to form a stream lambda expression something like this.  HashMap<String, List<String> > sortedmap = new HashMap<>(); sortedmap = map.values().stream().sorted(Map.Entry.comparingByValue((l1, l2) -> l1.get(0).compareTo(l2.get(0))) )   But it is not a valid lambda expression.  How do I do this with Java 8 streams?


How to calculate the expectation of the square of the number of heads in N tosses?

Suppose we have a coin that has a probability $p$ of landing head. Let H be the number of heads obtained in N tosses. How to calculate $E(H^2)$? I need this to calculate some other things. But I can't figure out. I know I need to take $\sum x^2p(x)$, but I am unable to evaluate it to a nice expression.


I have been googling and googling how to get this to work but everything i try gets me the same error. here is my code   package com.gwiddle.airsoftcreations.airsoftapp;   import android.os.Bundle; import android.support.annotation.NonNull; import android.support.v4.app.Fragment; import retrofit2.Call; import android.view.LayoutInflater; import android.view.View; import android.view.ViewGroup; import android.widget.Button; import android.widget.EditText;  import retrofit2.Callback; import retrofit2.Response;  public class SignUpFragment extends Fragment {  private EditText Name, Username, UserPassword;  private Button BnSignup;   public SignUpFragment() {   }  @Override public View onCreateView(@NonNull LayoutInflater inflater, ViewGroup  container,                          Bundle savedInstanceState) {      View view = inflater.inflate(R.layout.fragment_sign_up, container,  false);     Name = view.findViewById(R.id.name);     Username = view.findViewById(R.id.username);     UserPassword = view.findViewById(R.id.password);     BnSignup = view.findViewById(R.id.btnSignup);      BnSignup.setOnClickListener(new View.OnClickListener(){         @Override         public void onClick(View view){             performRegistration();         }     });      return view;  }  public void performRegistration(){     String name = Name.getText().toString();     String username = Username.getText().toString();     String password = UserPassword.getText().toString();     Call<User> call =  MainActivity.apiInterface.performRegistration(name,username,password);                  call.enqueue(new Callback<User>() {                 @Override                 public void onResponse(@NonNull Call<User> call, @NonNull   Response<User> response) {                      if (response.body().getResponse().equals("ok"))                     {                         MainActivity.prefConfig.displayToast("Ready to    Deploy.....");                     }                     else if (response.body().getResponse().equals("exist"))                     {                         MainActivity.prefConfig.displayToast("User Already   In Squad, Try again.");                      }                     else if (response.body().getResponse().equals("error"))                     {                         MainActivity.prefConfig.displayToast("KIA..  Something Went Wrong.");                      }                  }                 }                  @Override                 public void onFailure(@NonNull Call<User> call, @NonNull   Throwable t) {                  }             });      Name.setText("");     Username.setText("");     UserPassword.setText("");   }   }   I and my mate are both new to java and have spent all day trying to fix this  this is the error i get     E/AndroidRuntime: FATAL EXCEPTION: main                     Process: com.gwiddle.airsoftcreations.airsoftapp, PID: 20606                     java.lang.NullPointerException: Attempt to invoke virtual method 'java.lang.String   com.gwiddle.airsoftcreations.airsoftapp.User.getResponse()' on a null   object reference                         at com.gwiddle.airsoftcreations.airsoftapp.SignUpFragment$2.onResponse(SignUpFragment.java:64)                         at retrofit2.ExecutorCallAdapterFactory$ExecutorCallbackCall$1$1.run(ExecutorCallAdapterFactory.java:70)                         at android.os.Handler.handleCallback(Handler.java:809)                         at android.os.Handler.dispatchMessage(Handler.java:102)                         at android.os.Looper.loop(Looper.java:166)                         at android.app.ActivityThread.main(ActivityThread.java:7377)                         at java.lang.reflect.Method.invoke(Native Method)                         at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:469)                         at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:963)


Doing two Bachelors before Masters degree?

I currently study for my B.Sc. in Media IT. I easily could finish a second Bachelor if I do one more semester. I want to do master's degree in Media IT afterwards.  I'm already 23 and in the third semester, since I finished an apprenticeship as a software developer before. Is it useful to start my master's with 26 and probably finish it when I'm ~28?


If $p$ is prime and $p|ab$, then $p|a$ or $p|b$.

I am trying to understand why a line in the following proof is true. Suppose $p$ is prime and $p|ab$ where $a$ and $b$ are integers. If $p$ does not divide $a$, then $a$ and $p$ are coprime, and so there exist $x,y\in\mathbb{Z}$ such that $ax+py=1$. Then we have $abx+pby=b$ and $pby=b-abx$. Hence $p|b-abx$.  Now, the next line in the proof says that this implies that $p|b$. Why is this so?


SO mobile site "Your Answer" textbox appears on top of flag dialog

The "Your Answer" textbox seems to be eating the flagging dialog as shown in Figure A.


Is it possible for a matrix to be positive definite and have complex eigenvalues?

I was wondering if a matrix $A$ can be PD, but still have complex eigenvalues (with nonzero imaginary part).  I know for example that any symmetric/Hermitian matrix has real eigenvalues, but for example $A=\begin{pmatrix} 1 & 1\\0 &1\end{pmatrix}$ is neither, yet is positive definite.   From linear algebra I also know that the following statements are equaivalent:  1) $A$ is PD if $z^TAz>0 \;\forall z \neq 0$.  2) $A$ is PD, then all eigenvalues $\lambda_i>0$.  3) $A$ is PD, then $z^TAz>cz^Tz$ for some $c>0$.  I'm mostly concerned abou the second statement, so if it would possible for a PD matrix to have complex eigenvalues, how does this relate to $\lambda>0$? Are we only considering the real part?   At this point I am wondering if these statements are even true for the complex case, since in classes you usually see examples like $z^TAz = c_1z_1^2+c_2z_2^2$, (considering some $A\in\mathbb{R}^{2\times 2}$) where $c_1$ and $c_2$ are some positive constants. This however works only for real $z$, since if for example $z = [i\quad 0]^T$, this argument already breaks down.  Looking at for example Wikipedia seems not very helpful, since this only considers Hermitian/symmetric matrices, which I am specifically not interested in.   Summarising  I am interested in the possibilities of having PD matrices with complex eigenvalues. I am not particularly interested in a simple yes or no (even though this would be a great starting point), but more in what the consequences of such a situation are. How does this relate to the above statements? Do I oversee some principles ideas which even contradict this being possible?


Biber and Biblatex: reference to multiple subentries

I am using biblatex with biber for my thesis. I use sets to have several subentries:    When I refer to multiple subentries (e.g. a & b) of one set, I would like an output as: [1a,b], but instead I get [1a,1b]:    Is there a way to solve this? And also something like: [1a-c]?  \RequirePackage{filecontents} \begin{filecontents}{test.bib} @article{author1, journal = {journal}, year = {1999}, author = {author1}, }  @article{author2,   journal = {journal}, year = {1999}, author = {author2}, }  @article{author3, journal = {journal}, year = {1999}, author = {author3}, }  \end{filecontents} \documentclass[12pt,a4paper, headinclude=true, titlepage=true,DIV=12,oneside,BCOR=1cm, numbers=noendperiod, toc=bib, chapterprefix=true]{scrreprt}  \usepackage[babel,german=quotes]{csquotes} \usepackage[backend=biber,citestyle=numeric-comp,bibstyle=chem-angew,mcite=true,subentry,pageranges=true,sorting=none,citetracker]{biblatex} \addbibresource{my_refs.bib} \usepackage[ngerman,KeepShorthandsActive]{babel}                    \usepackage[utf8]{inputenc}                    \usepackage[T1]{fontenc}  \addbibresource{test.bib}  \begin{document}  Here I cite a reference with several    subentries.\defbibentryset{set1}{author1,author2,author3}\supercite{set1} Somewhere later, I want to refer to some of the subentries.\supercite{author1,author2}  \printbibliography  \end{document}


Though we use adjectives before nouns normally, why are some words exceptions like 'something'? Why do we use the adjectives after them?

For example: something , everything, anything, nothing ... special  someone , everyone , anyone,, no one ... special  somebody , everybody , anybody , nobody ...special


$7$ points inside a circle at equal distances

BdMO 2014     There are $7$ points on a circle.Any 2 consecutive points are at equal distance from one another.How many acute angled triangles can you form taking any 3 of these points?   I believe there are 5 possible triangles that we can form using any three points.Then we can find out which of these are acute-angled.Then we can compute the number one by one and sum them up.Am I right?


so I have this really frustrating problem every time I try to create a new thread for a function that has do perform some operations involving the UI controls.  all I need this for is to be able to break out of this loop when a button in the GUI is pressed but that doesn't happen because the button is not responsive until this method is finished executing. is it possible to maybe just run that button on a separate thread and make it change a volatile variable or something like that (a simple elegant solution) instead of having to modify every single thing in this method.  I've read a most of the previous question and have tried some stuff but it never seems to work. I don't understand why something so intuitive is so hard to accomplish.  Here is the function I'm referring to:  private void pbPlay_MouseDown(object sender, MouseEventArgs e) {     pbPlay.Image = Resources.play_d;     //playBack();     T3 = new Thread(playBack); T3.Start(); }  private void playBack() {     var frameTime = new DateTime(); var frameTime_ = new DateTime();     int playTime = 0; ;     trPlay.BeginInvoke(new Action(() =>         {             playTime = trPlay.Value;         }));      playGoStop = true;      lbPlayTime.BeginInvoke(new Action(() =>         {             lbPlayTime.Text = (playTime * numDtStepSize.Value).ToString();         }));       while (playTime < trPlay.Maximum + 1)     {         frameTime = DateTime.UtcNow;         if ((frameTime - frameTime_).TotalMilliseconds > (double)(1000 / numFps.Value))         {             //systemUpdate(playTime);             //trPlay.Value = playTime;             //trPlay.Update();             lbPlayTime.BeginInvoke(new Action(() =>                 {                     lbPlayTime.Update();                 }));              frameTime_ = frameTime;             playTime++;         }         if (!playGoStop) break;     } }   So the BeginInvoke I've added after reading about it in some other threads but it doesn't work and it keeps crashing. there are a bunch of GUI operations taking place in this function both get and set, I hope there is a way of handling this without having to go through so many hoops for every single operation.  In this particular case I'm running this function on a separate thread because I need my UI to stay responsive while the function executes, and I need to be able to change the variable playGoStop when I click on a pause button while this code is executing.


I want to mount /usr directory on different partition and keep the same owner on all files and subdirectories in /usr directory.  I want to mention that this issue is for linux ec2 machine where I can't enter to the single-user runlevel.  Is it possible?


How do electrons that constitute a current flow move in a wire? Some say it's like a wheel.If you give it a push,every part of the wheel moves instantly. Is that what happens to electrons?Do they start moving everywhere in the wire when the circuit is closed? Why? Or is it because electrons bump into each other and the energy travels at the speed of light?


In Linux, in /proc/PID/fd/X, the links for file descriptors that are pipes or sockets have a number, like:  l-wx------ 1 user user 64 Mar 24 00:05 1 -> pipe:[6839] l-wx------ 1 user user 64 Mar 24 00:05 2 -> pipe:[6839] lrwx------ 1 user user 64 Mar 24 00:05 3 -> socket:[3142925] lrwx------ 1 user user 64 Mar 24 00:05 4 -> socket:[3142926] lr-x------ 1 user user 64 Mar 24 00:05 5 -> pipe:[3142927] l-wx------ 1 user user 64 Mar 24 00:05 6 -> pipe:[3142927] lrwx------ 1 user user 64 Mar 24 00:05 7 -> socket:[3142930] lrwx------ 1 user user 64 Mar 24 00:05 8 -> socket:[3142932] lr-x------ 1 user user 64 Mar 24 00:05 9 -> pipe:[9837788]   Like on the first line: 6839. What is that number representing?


sorry for the language. I just can't understand why it wont enter the first while loop and goes straight to the end. The while starts with a boolean but it just wont proceed.  I could use some help :) Thanks in advance. Now its at its (half) full. It doesn't have anything to do with equaling strings. Thanks again.  package guessTheNumber;  import java.util.Random; import java.util.Scanner;  public class Main {      public static void main(String[] args) {          //Opening of the scanner.         Scanner guess = new Scanner (System.in);          //Entry - what the player will see before he starts.         System.out.println("Hello.");         System.out.println("Wellcome to the Guess the number game");         String enter = guess.nextLine();         System.out.println("I choose a nember and you have to guess what it is.");         enter = guess.nextLine();         System.out.println("Ready?");         System.out.println("I don't care... Type NEW to start");          String startGame = guess.nextLine();          while (startGame == "NEW" || startGame == "New" || startGame == "new"){              //generates new number             Random newNumber = new Random();             int newRandom = newNumber.nextInt();             //here the player can guess the number             System.out.println("I chose a number between 1-bitch. what number am I thinking of? ");           //if the player chooses to end the game         System.out.println("See you later mother ******.");      }  }


How can I change a defunct Apple ID email address?

I never changed my student email account to which all app purchases have been made. I just upgraded to iOS 5, and it requires to authenticate the iCloud, by verifying an email sent to the now defunct email address. The problem is that I can't even change my email adress, because the system wants to verify my iCloud account first. It's a circular problem!  Can't change email because I haven't verified iCloud, and I can't verify iCloud because my old email is now defunct.  What can I do??


I would like to publish my work which is a chapter of my doctoral thesis. One chapter has already been published with myself as a first author and my advisor as an second author. Since I'm working in a private company as a full time employee, I wonder what should be my affiliation. The work was completely done when I was a graduate student, but now I left the school. I'm a full time employee now, but this work has nothing to do with my current employer. What should be the my affiliation in my paper? The school I graduated, or my current employer?


A 3.5mm jack broke into my mac's jack input and I can't take it out (we tried for a day, it's absolutely impossible) and because of that my MacBook detects a plugged in audio output. I can't listen music or audio output on my Mac's speakers.  Is there a way to force the sound to come out from speakers, even while the system detects a plugged in jack?


Where is source code of QGIS Processing algorithms?

I am beginning to learn QGIS 3 up from QGIS 2.  I see many changes. In QGIS 2 one could find the scripts for the algorithms located in the Processing Toolbox but in QGIS 3 I cannot find them (for example, RandomExtract.py file). Can someone direct me to the path?


How to implement this in C# 4 with extensions:  string challengeId; if(challengeId == mViewModel?.Challenge?.Id)      where Challenge.Id is string   I  some extension:  public static TValue GetOrDefault<TObject, TValue>(this TObject obj, Func<TObject, TValue> getter, TValue defaultValue = default(TValue))             where TObject : class         {             return obj == null ? defaultValue : getter(obj);         }   then i can use it so:  string challengeId; if(challengeId == mViewModel.GetOrDefault(x => x.Challeng).GetOrDefault(x => x.Id)   will be this ok in all combinations. What about if Id's are not string and we want to compare int?  int challengeId;     if(challengeId == mViewModel.GetOrDefault(x => x.Challeng).GetOrDefault(x => x.Id)      where Challenge.Id is int


Will my warranty be valid in other countries if I buy an iPad in Korea?

I will be in Korea for 5 months, I'm about to buy an iPad 2 there and I'll be back in London or France in September. I would like to know if my warranty will be valid in England or in France in case something happens because there are no Apple Stores in Korea, but only retailers.


How to render the black lines at the edges of an object?

How to render an image like this with black lines ?     Image taken from the following faceboock page:


var_a (can be any variable name) should be replaced by its value:  var_a = "Hello"  var_b = "var_a world"  print var_b   Output should be: Hello world


I'm trying to connect a BNO080(IMU) to my microcontroller on a PCB. There are capacitors at the voltage input to the IC and I don't properly understand what these capacitors are doing or how their values are determined to be 0.1uF. Any help?


Defining extern template specialization in template declaration header

I have a template function with a quite common specialization, that I would like to instantiate only once in a library to avoid unnecessary code compilation. To this end I'd like to use extern template in the header declaring the main template, so that every translation unit including the header won't instantiate the template. For example: // ******** test.h *******  #include <iostream>  template <typename T> void f(T t){     std::cout << t << std::endl; }  extern template void f<int>(int t);        // ******** test.cpp *******  #include "test.h"  template<>    void f<int>(int t){ }  template void f<int>(int t);  Compiling with g++ I get this error: $ g++ test.cpp test.cpp:4:18: error: specialization of 'void f(T) [with T = int]' after instantiation     4 | void f<int>(int t){       |                  ^  If I remove the extern template from the header the code compiles fine. I don't clearly understand where the error lies nor how to eventually fix it. Thanks in advance for any help.


I'm trying to install packages from terminal but experiencing problem such that:  tarlan@tarlan:~/Downloads/git-2.9.5$ sudo apt install git [sudo] password for tarlan:  Reading package lists... Done Building dependency tree        Reading state information... Done Package git is not available, but is referred to by another package. This may mean that the package is missing, has been obsoleted, or is only available from another source However the following packages replace it: git-svn git-el  E: Package 'git' has no installation candidate tarlan@tarlan:~/Downloads/git-2.9.5$ sudo apt install git-svn Reading package lists... Done Building dependency tree        Reading state information... Done Some packages could not be installed. This may mean that you have requested an impossible situation or if you are using the unstable distribution that some required packages have not yet been created or been moved out of Incoming. The following information may help to resolve the situation:   The following packages have unmet dependencies:  git-svn : Depends: git (> 1:2.14.1) but it is not installable        Depends: git (< 1:2.14.1-.) but it is not installable        Depends: libsvn-perl but it is not installable        Depends: libyaml-perl but it is not installable  E: Unable to correct problems, you have held broken packages.     It appeared after installing ubuntu to my PC. I thought the problem is rooted in held broken packages  I tried  this way.    The problem in this answer couldn't help me as couldn't list held packages.  dpkg --get-selections | grep hold     I also wanted try to use this way  sudo aptitude -f install <packagename>   The problem is that i don't know the broken packages.    Please help me, i'm new here and trying to adapt to Ubuntu so any suggestion will be welcomed    Editted  I also tried this way:  sudo apt-get -f install   and experienced this and again saw the previous issue:  tarlan@tarlan:~/Downloads/git-2.9.5$ sudo apt-get -f install [sudo] password for tarlan:  Reading package lists... Done Building dependency tree        Reading state information... Done 0 upgraded, 0 newly installed, 0 to remove and 0 not upgraded.


In Object Mode I sometimes see these black dotted lines starting at some of my objects and ending in some random spot in the space. What are they, how do I manipulate them, and why?


Prove that the complex function $f(z) =\frac{z}{1+|z|}$ is injective

I'm trying to prove that the complex function $f(z) =\frac{z}{1+|z|}$ is injective and have made the following start. Assume there exists some $z=x+iy$ and some $w=a+ib$, Then $f(w) = f(z)$ implies that $w=z$ which would prove that the function is injective. We have $\frac{w}{1+|w|} = \frac{z}{1+|z|}$ Then $w = z \ \frac{1+|w|}{1+|z|}$. This is where I struggle to see the next step. I know that I want to prove that $|w| = |z|$ and therefore $1+|w|=1+|z|$ but I can't see how to do this without making premature assumptions. Furthermore, the question states "prove by using polar co-ordinates or otherwise" but again I'm not sure how this is helpful as far as I can see I will still be in the same position at this step even in polar form. Any help or advice with this question would be very much appreciated. Thank you!


How to change the disk space left warning in Windows 7?

my disk has over 100GB of free space, but the usage bar in Computer is displayed in red, as if it reached a low space limit. It looks like Windows applies the same 10% or 15% hard disk space value for low space warnings, regardless of if the disk is 50GB in size or 1.5TB, which is not very smart and obsolete for most recent computers.  Is there a Registry key or some place I can change this percentage so the usage bar displays in green, not red?  The hibernation and page files are already reserved (5GB together), so surely the low space warning for a 1.5TB disk should be 5-10GB, not 150GB or more. The way Windows 7 computes the low space limit seems pretty dumb, not much Intellisense there.  This is not a high priority issue, but it makes the Computer applet look pretty stupid and it's irritating every day to see that 100GB of free space is putting my computer in the red. It would also be nice to be able to edit this low limit percentage in Computer/Manage/Storage/Disk Management or directly in the disk properties ("Tools" tab).


How to implement a file download in asp.net

What is the best way to implement, from a web page a download action using asp.net 2.0?  Log files for a action are created in a directory called [Application Root]/Logs.  I have the full path and want to provide a button, that when clicked will download the log file from the IIS server to the users local pc.


It's not yet 18th December 2015 but I have earned the A New Hope hat on Stack Overflow which says:      ask, answer, or vote on December 18th   Proof:     Possible Bug?


lualatex: emergency stop when including a file from subfolder and setting aux/output directories

I have a main file including many files from the same subfolder. I get lualatex working in case:   I include the files from the subfolder and let the aux/pdf files be generated in the main directory I don't include any file from the subfolder and set the directories aux/output to different subfolders.   However, when I include files from the subfolder and set aux/output directories I got an error     Emergency stop. \include{SourceFiles/Ch2_Literature}      I can't write on file `SourceFiles/Ch2_Literature.aux'. \include{SourceFiles/Ch2_Literature}   where I don't understand why it looks for aux file in the subfolder instead of the aux-directory I already set.


My Windows 7 64-bit laptop will not boot up

This is exactly what it says  For Realtek RTL8101E/8102E PCI-E Ethernet cable controller v1.08 (080408)  PXE-E61: Media test failure, check cable  PXE-M0F: Exiting PXE ROM.  No bootable device -- insert boot disk and press any key  Here is another message i get  Windows has encountered a problem communicating with a device connected to your computer.  This error can be caused by unplugging a removable storage device such as an external USB drive while the device is in use or by faulty hardware such as a hard drive or CD-ROM drive that is failing. Make sure any removable storage is properly connected and then restart your computer.  Status: OxcOOOOe9 Info: An unexpected I/O error has occured.  I dont understand what happened. I was on the internet and then my computer was turned on(This makes me lose wifi) and i tried going to a different URL then my laptop went to this error screen.  If you have any advice please tell me. Many thanks, Joseph Milo


Short story - Man and beautiful girl are space tourists who visit disasters in galaxies

Read this in early 1980s - man meets up with a beautiful girl with equally beautiful friends.  They are space tourists who visit disasters across galaxies and who are in town (San Francisco?) to await the catastrophe which is about to occur.


I have a Nikon D7000 and need to buy a polarising lens but don't know what size lens I need. I have the the starter kit lens AF-S Nikkor 18-105mm1.35-5.6g ED. I'm new to photography.


Windows 10 calculator and regional settings

I have Windows 10 with English lanugage. In regional settings I have set Denmark and my keyboard is Danish.  The Windows Calculator (calc.exe) seems to have switched "." and ",", like used in USA. When I enter "," on my keyboard it writes ".". , and . works as expected in other programs like Excel.  Is this just the way the Windows 10 calculator behaves or can I change it?


Could someone show me how to multiply in say $S_4$. I know how to multiply say $(4321)(2341)$ but when it comes to ones that do not contain $4$ terms, like $(34)(231)$, I have no idea how to handle this. We do from left to right.


Am just trying Ubuntu and have the latest (18.04). After install I can't print. After going through several steps it says I need the plugin.  After running hp-plugin here's what I get:  Checking for network connection... Downloading plug-in from:  Plugin is not accessible. Trying to download it from fallback location: [https://developers.hp.com/sites/defa...12-plugin.run] Receiving digital keys: /usr/bin/gpg --homedir /home/dallas/.hplip/.gnupg --no-permission-warning --keyserver pgp.mit.edu --recv-keys 0x4ABA2F66DBD5A95894910E0673D770CDA59047B9 Creating directory plugin_tmp Verifying archive integrity... All good. Uncompressing HPLIP 3.18.12 Plugin Self Extracting Archive........................................... ..............  HP Linux Imaging and Printing System (ver. 3.18.12) Plugin Installer ver. 3.0  Copyright (c) 2001-15 HP Development Company, LP This software comes with ABSOLUTELY NO WARRANTY. This is free software, and you are welcome to distribute it under certain conditions. See COPYING file for more details.  Plug-in version: 3.18.12 Installed HPLIP version: 3.18.12 Number of files to install: 55     Plugin installation failed error: Python gobject/dbus may be not installed error: Plug-in install failed.   Any ideas?


How can black holes have charge and gravitate?

I seem to misunderstand the whole concept of .  Let`s imagine a charged black hole. It does not let out anything that travels at any speed less than or equal to the speed of light, right?  So how can we even know the black hole is massive and it has a charge if nothing (which also includes all force-conveying particles) can be faster than light?  Okay, for quantum gravity there is no conclusive theory as of now, and the graviton is yet to be discovered experimentally. But what about the electric charge?


Open an .ico file in Photoshop or Illustrator?

I have some icons I'd like to purchase and use from iconfinder.com, but they are only available as .ico files. I want to use these as part of a user-interface on a website, so I need them as either bitmap or vector format that I can bring into Photoshop to produce transparent .png files.  Does anyone have any suggestions on how to get .ico files into Photoshop through some third-party application? If it matters, I am using a Windows computer.


I was looking around for installing a custom recovery and then a custom firmware on my old phone, but I couldn't any links that were still available and not adware ridden, can anyone give me some advice on where to search?


Is the following phrase grammatically correct:  Suffering from anxiety and depression, life has been a tremendous challenge for him ever since he was a young boy.


Is it possible to get a decimal output from doing division in Bash?

Basically in Bash, what I'm trying to do is take a input of seconds from a user and find the hours. So basically if the user enter 35 the output should be 0.00972222.  But bash gives me is a zero.  heres the command I have:  echo "Enter the seconds you wish to convert to hours: " && read sec && echo " $((sec/3600)) is the amount of hours "   Is there a way I can make it so it prints out 0.00972222 if I enter 35.  Thanks!


How to prove $\log n \leq \sqrt n$ over natural numbers?

It seems like $$\log n \leq \sqrt n \quad \forall n \in \mathbb{N} .$$ I've tried to prove this by induction where I use $$ \log p + \log q \leq \sqrt p \sqrt q $$ when $n=pq$, but this fails for prime numbers. Does anyone know a proof?


What is the meaning of "${name##*/}" in Shell

I have a code as  while read name; do uuencode "$name" "${name##*/}"; done   but I do not understand what is meaning of ##*/ in "${name##*/}"  Google doesn't give good results. Can someone please explain.


Gmail account reset but I don't have the same 'phone number to get the reset code

I'm trying to reset my password to my Google Account.   I do not have the same phone number to get the reset verification code.   What to do now?


Calculating minimum velocity of the projectile needed to hit target in parabolic arc

If I have a point which I want to hit at the end or during a parabolic arc, how would I calculate the needed x and y velocity?


How can I distribute $9$ people in $3$ groups of $3$ people? The order of the groups and the order of the people doesn't matter.  I would like to know the procedure to solve it. The solution is $280$.


This one has always bothered me.  Is this sentence correct?     He shivered, thinking about his and Anya’s first time in the hospital.   It feels awkward, but there's a need to refer to their shared experience.  This would also apply to something like:     I shivered, thinking about mine and Anya's first time in the hospital.   Again, it clunks, but I can't see an alternative.


Is there any keyword in Java which is similar to the 'AS' keyword of C#

As we know C# provides an AS keyword which automatically performs a check whether the Object is of a type and if it is, it then casts it to the needed type else gives a null. public class User { }  Object obj = someObj; User user = obj As User;  Here in the above example, An Object obj can be of type User or some other type. The user will either get an object of type User or a null. This is because the As keyword of C# first performs a check and if possible then performs a casting of the object to the resulting type. So is there any keyword in Java which is equivalent to the AS keyword of C#?


Could humans choose to establish fibre digesting colonies in our guts?

Humans don't digest fibre, and nor do any animals, but some creatures have micro-organisms (bacteria, I'm guessing) in their gut which digest fibre for them.  My question is, could humans take some sort of pill and establish our own fibre-digesting colonies in our intestines?  Has this been tried?  Supposing it could be done, would you suppose it would have any negative effects on our health?  (i.e.. would those whose gut digested fibre for them be stuck on a low-fibre diet?).    Purpose of question: just wondering.  It would be cool to be able to eat bark.


How to 'bind' Text property of a label in markup

Basically I would like to find a way to ddo something like:  <asp:Label ID="lID" runat="server" AssociatedControlID="txtId" Text="<%# MyProperty %>"></asp:Label>   I know I could set it from code behind (writing lId.Text = MyProperty), but I'd prefer doing it in the markup and I just can't seem to find the solution. (MyProperty is a string property) cheers


How to redirect output of a running program to /dev/null

I know that in order to suppress the output of a program I can redirect it to /dev/null, for example to hide all error and warning messages from chromium I can start the program like this  chromium-browser 2> /dev/null &   However, if I happen to forget about the error messages and type  chromium-browser &   (which is quite annoying when they appear in the middle of a command) I don't know what to do except for stopping the application and starting it again properly.  Can I somehow redirect error output without restarting the application?


WinEdt: How to open the new PDF compiled without closing the old-one?, compiled minutes ago

Using WinEdt 10.2 on Windows, when I compiled a doc, automatically WinEdt opens  the PDF with Acrobat Reader. And If I didn´t close that viewed file, I recompiled again  and  WinEdt closes the old PDF and show me the new one.  But I made any changes, or WinEdt copied the settings from my installed WinEdt 9,... and now... If I close the PDF, and then compile, WinEdt opens the just-compiled PDF with Acrobat Reader   BUT  If I didn´t close the old PDF, Winedt can´t open the new PDF with Acrobat Reader as weeks ago, and show me that message:   How could I show the new PDFs without closing the old one just-compiled a minutes ago?  I usually use   Excuse me for my little English.


Is there a security risk if a password can be reset easily?

was just reading up on changing password complexity and I stumbled upon this:     Isn't that a big security risk?  Assuming someone gets a hold of the physical box/laptop? I know with windows there is a requirement for using a password reset disk. But, I assume if anyone gets a hold of an HDD/SSD they can read the info on it assuming the file system hasn't been encrypted. But this, even with encryption, seems that anyone can reset the password for the system if they are at the terminal.


I'm playing a game of Civ V and I captured a city that needed a new production. I sold the city that turn and now the choose production icon is stuck and wont go away even when I press shift-enter. Is there a way to skip the "Choose Production" option for a city for a turn?


I got into an argument today about the role of the Rebel Alliance and the Empire in the Galactic Civil War. My opponent posits the Galactic Empire is not inherently evil, and the Rebels would just be terrorists from their point of view. She felt the oppression and fear of violence they were fighting against were only brought on because of the existence of the Rebel Alliance in the first place.  Are there specific examples of "evil" actions taken by the Empire unprovoked, or were all their actions "justified" by rebellion? I tried to bring up , , and Alderaan, but my opponent felt they were justified because the Empire was provoked and needed to keep the peace. I also brought up Order 66, but they argued that was Darth Sidious using the Empire as a vehicle for his whims, not the empire itself.  Thank you in advance!


Constant binding to event listener Jquery

I am having a bit of an issue. I want to bind elements (in Jquery) to an event Listener. I would normally do it in the $(document).ready() but these elements are not created yet in the body, so they are not binded with the event listeners. I would like to know if there is a way of doing this so I don't have to bind the elements every time I create a new element.  The elements are created like this : $("#theDiv").html(functionReturningHTMLString())  Thank you all


javascript---click copy the content to the clipboard

the following is the code. but it doesn't work. what's wrong with it? thank you.        <head>    <meta http-equiv="Content-Type" content="text/html; charset=utf-8" />      <title>no title</title>    <script type="text/javascript">       function copyToClipBoard(content){  var clipBoardContent = '';  clipBoardContent = content;  window.clipboardData.setData("Text",clipBoardContent);  alert('have copied to the clipboard'); }            <body> <textarea rows="4" cols="60" id="url">www.example.com</textarea>      <input type="button" value="click me" onclick="copyToClibBoard (document.getElementById   ('url').value);" />  </body>


I am trying to pick the display name, mobile number from the contacts in phone and showing these in a list by using a list view. But I'm getting null pointer exception while running the following code:  public class SeeActivity extends ListActivity {     public String [] allname;        public String [] allnumber;        public int listcount=0;        public String [] details;        String[] PROJECTION = new String[] {                ContactsContract.CommonDataKinds.Phone.DISPLAY_NAME,                ContactsContract.CommonDataKinds.Phone.NUMBER            };       @Override     public void onCreate(Bundle savedInstanceState) {         super.onCreate(savedInstanceState);         setContentView(R.layout.main);   ;          Cursor phone= getContentResolver().query(ContactsContract.CommonDataKinds.Phone.CONTENT_URI,PROJECTION ,null ,null ,null);         try{         while(phone.moveToNext())         {               String name= phone.getString(phone.getColumnIndex(ContactsContract.CommonDataKinds.Phone.DISPLAY_NAME));            String number=phone.getString(phone.getColumnIndex(ContactsContract.CommonDataKinds.Phone.NUMBER));            allname[listcount]=name;            allnumber[listcount]=number;            details [listcount]=name+"    "+number;            listcount=listcount+1;          }         ArrayAdapter<String> adapter = new ArrayAdapter<String>(this,                 android.R.layout.simple_list_item_1,details);         setListAdapter(adapter);         ListView l=getListView();            l.setOnItemClickListener(new OnItemClickListener() {              public void onItemClick(AdapterView<?> arg0, View arg1, int arg2,                     long arg3) {                 Toast.makeText(getApplicationContext(),((TextView)arg1).getText() , Toast.LENGTH_SHORT).show();               }         });}        catch( Exception e)        {            Toast.makeText(getApplicationContext(),e.toString(),Toast.LENGTH_LONG).show();           }        }   }


Linux shell script check command success

I need to check the command executed is success or not, I have place the below code in test.sh run it, which give the out by listing the content of /home but there is a warning   ./test.sh: 3: ./test.sh: [[: not found   What's wrong in below command  #!/bin/sh ls /home/ if [[ "$?" != 0 ]]; then echo "Commnad Error" else echo "Commnad Success" fi


find first index of array in string javascript

There is a string variable that has a path like /app/something/xx/4/profile besides there is an array of string like **  const arr=[      {name:'xx',etc...},       {name:'yy',etc...},      {name:'zz',etc...}     ]   I want to find the first index of array that the string variable has the name in simplest way.


I want to search a pattern from one file in another


Prove that If $m'$ is a common multiple of $s$ and $t$, then $m | m'$. Here $m$ is the LCM of $s$ and $t$.    Although the statement is intuitively clear to me I don't know how to prove.


Use of "would rather" with different subjects

I've read that "would rather" has two different constructions; same subject and different subjects.  Some of the examples have been listed below:        I would rather they did something about it.      Question 1:  Does it mean "I would prefer them to do something about it" at present moment or in the future?         Rahul joined Engineering but he'd rather has joined medicine.      Question 2.  Does it mean "He would have preferred to join medicine but he joined Engineering"        I would rather you stayed at home tonight.      Question 3. Can't we just say "you would rather stayed at home tonight." Without changing the meaning of above sentence?  Source:   Note: I have read this question  which is a bit similar to my question because both are about "would rather". But all the example sentences and questions that  I have asked in my question are different.


How can you tell when a roast is done?  How long should they roast for?


In my campus i am using a power supply unit, in order to supply 5V and 0.02A, to my analog circuit that interacts with a microcontroller.  I am unable to go to the university because of work, and i want to take the circuit and the microcontroller to my house for programming work.  It's easy to carry the circuit that resides in a breadboard and the microcontroller, but i cannot take the big power supply.  So i want to provide 5V and 0.02 amps to the circuit.  I have never worked with power supplies before.  From a multi transformer i have in my house, i can get the voltage right. Heck, even USB proved 5V. I could solder some wires and provide supply to my circuit from the USB cable.  What i don't know is the amps. How will i be able to provide 0.02A to the circut?  Can i buy smoe power supply wit hthis value, or eevn varying amperes? Can i create a circuit that will amke sure i am supplying 0.02A?


How do I evaluate $\cos(x) + \cos (2x) +\cos (3x) + ... + \cos (nx)$?

How to evaluate the above expression and express the answer in terms of $n$ and $x$?


How badly will bad grades impact future college and career life?

So, I'm currently an upcoming sophomore in undergrad and my grades during freshman year weren't the best. I got a F during my second semester which gave me an overall freshman GPA of 2.9  I'm not too worried about the GPA since I still have time to improve it.  However, the F on the transcript is really stressing me out. As of now, my school says I cannot retake and replace the F on the transcript.  Even if I increase my GPA to at least a 3.7 but still have 1 F on my transcript, how badly will if affect my chances of getting into a good grad school or getting internships?


"See somebody do" and "see somebody doing"

My grammar book says that if you saw the complete action you use do/get/drive: "I saw him fall off the wall." Otherwise you use -ing: "I saw him standing at the bus stop." A native American speaker said that he doesn't agree with that and there is no difference whether you use -ing or not. He said that particularly in these situations I can use either verb without affecting the meaning:  —How do you know I took the money? —I know it because I saw you take / taking it. —How did the woman fall? —I don't know. I didn't see her fall / falling.   He couldn't come up with a situation where this rule makes sense. But I tried to come up with such situation and he said that in this case it can be true.  I saw him eat the whole plate of pasta.  He ate everything that was on the plate. I saw him finish it.  I saw him eating the whole plate of pasta.  I saw how he was eating from a plate full of pasta. But I'm not sure whether he ate everything or not. I didn't see him finish it.  Please comment on what has been said. And give your opinion about this rule.


What's the physical appearance of Dragonborns?

I'm looking for a miniature for my Dragonborn fighter. I know the basics but I haven't really find anything definite about the the little details, like the shape of the legs and if they have tails.


About equivalences of linear functionals on a real vector space $X$

Suppose we have a real vector space $X$ and $\varphi_1,\varphi_2,...,\varphi_n$ and $\psi$ linear functionals from $X$ to $\mathbb R$. I'm struggling with the following implication:  $$ "ker(\psi) \supset \cap_{1\le k \le n}ker(\varphi_k)" \implies " \exists \lambda_1,\lambda_2,...,\lambda_n \in \mathbb R: \psi=\sum_{1 \le k \le n}\lambda_k \varphi_k" $$  What I've tried so far was passing to the quotient $X/\cap_{1 \le k \le n}ker(\varphi_k)$ and then defining the unique linear functional $$\varphi: X/\cap_{1\le k \le n}ker(\varphi_k) \to \mathbb R, \space [x] \mapsto \psi (x)$$  I don't know how to proceed and to be honest I don't even know if this is the right approach but the kernel intersection immidiately triggered the idea to pass to the quotient.  Any help?


How to do a bezier interpolation mode animation along a path?

When I parent an object to follow a path and animate it, I only get a linear mode animation and changing that in Grapth Editor to bezier doesn't work! How to do that?


How to reload media parttion table after dd

When I overwrite the partition table with dd command I can't mount my new partition mmcblk0p1 because is not updated  I need to force reload partition table of SD-Card mmcblk0, I unplug and plug SD-Card for update /dev/mmcblkp1 or run gparted Ctrl+R for reload media.  I search a bash command for it.


How can I determine whether a given SSD and motherboard are compatible?  For example, I have an OCZ Vertex 2 OCZSSD2-2VTX50G 2.5" 50GB SATA II MLC Internal Solid State Drive and a GIGABYTE GA-H67A-UD3H-B3 LGA 1155 Intel H67 HDMI SATA 6Gb/s USB 3.0 ATX Intel motherboard.


Why do forked processes sometimes appear with brackets [] around their name in ps?

On a Linux system a C process is started on boot, which creates a fork of itself. It is not a kernal process or something. In most cases a ps -ef show both processes as expecxted, but sometimes it looks like the following:   1258 root       0:00 myproc  1259 root       0:00 [myproc]   i.e. one of the processes surrounded by brackets. According to ps:  If the arguments cannot be located (usually because it has not been set,  as is the case of system processes and/or kernel threads) the command name  is printed within square brackets.   I do not understand what it means when the 'arguments cannot be located'. The process is started always exactly the same, and the fork is always created in the exact same way. How can it happen, that sometimes 'the arguments cannot be located' and sometimes they can?   In addition, the process is always started without any arguments...  Questions I have:    What do those brackets really mean? Does the process run at all when /proc/{pid}/cmdline is empty? Why do I get those brackets sometimes and not always? How/Where to fix this problem?   Additional information:   The process is always started without any arguments! Just the name of the command myproc. The main process seems to run always correct (no brackets around name, executable in /proc/x/cmdline). The child process sometimes has its name in brackets. The content of /proc/child-pid/cmdline of a correct running child process is myproc. The content of /proc/child-pid/cmdline of an incorrect running child process is empty! Again: same code, different child processes!


The c function with param such as :   void test(int fp, int &pos){ //do something... }   But i don't understand what does "int &pos" meant . Thank you very much for your help


'java.lang.String java.lang.Object.toString ()' on a null object reference (Firebase)

I tried to get extras from the intent in recyclerView and display it in detail but when I tried it there was a      java.lang.NullPointerException error: Attempt to invoke the virtual   method 'java.lang.String java.lang.Object.toString ()' on a null   object reference   public class NotifDetailAct extends AppCompatActivity {  DatabaseReference reference; TextView xdeskripsi;  @Override protected void onCreate(Bundle savedInstanceState) {     super.onCreate(savedInstanceState);     setContentView(R.layout.activity_notif_detail);      xdeskripsi = (TextView) findViewById(R.id.xdeskripsi);      Bundle bundle = getIntent().getExtras();     final String tittle_baru = bundle.getString("tittle");       reference = FirebaseDatabase.getInstance().getReference().child("notif").child(tittle_baru);     reference.addListenerForSingleValueEvent(new ValueEventListener() {         @Override         public void onDataChange(DataSnapshot dataSnapshot) {             xdeskripsi.setText(dataSnapshot.child("isi_notif").getValue().toString());         }          @Override         public void onCancelled(DatabaseError databaseError) {          }     }); }   }     java.lang.NullPointerException error: Attempt to invoke the virtual   method 'java.lang.String java.lang.Object.toString ()' on a null   object reference


I am working in a text that I use the following: "I measure the similarities between companies." There are many companies, but I evaluate the similarity "between" 2 companies. I mean if I have 3 companies, namely A, B, C, I have to evaluate the similarities in pairs and I provide the similarity between A and B, B and C, and A and C, i.e, three measures of similarities. My doubt is the text above should be "I measure the similarities among companies." Or is it correct?


How to find source of spamming knowing the spam mail header?

Context: I have a Dedicated Server hosted on Digital Ocean, called as "Droplet" and then, on it i have installed CentOS 6, and my mailing server is using EXIM. Problem: I am having spam issues on my server, i am being blacklisted and Digital Ocean is blocking my SMTP due to pishing, so i need to find where is the source of the spam to close the security breach or delete the potencial spam or somewhat else. Something that i've tried: Here on the image, as you can see i found the emails that are the spam problem in my exim mail server, by the way i dont know how to see where is the source of that email, i can access the spam mail header and i know from what recipient and to what recpient that the email is going, as far i know the header.  The thing is that im a little new on that and i dont know how to identify and close the problem, any hints for that?? Important: I do not want to know what i need to do, because i already know that. The thing is that i want to know how to do that.


Given n integers, show that there is a subset whose sum is divisible by n.

I’ve tried this. Let the integers be $a_1, a_2,...,a_n$. On dividing any number by $n$, we have $n$ possible remainders which are $0,1,2,...n-1$. Let these $n$ remainders be $n$ pigeonholes. From the $n$ integers available, we can form $2^n - 1$ possible subsets, assuming each subset must contain at least one element. Each subset is assumed to be a pigeon. $2^n - 1$ is always greater than or equal to $n$, for all values of $n$ greater than or equal to 1. So, the pigeonhole of the remainder 0, must contain at least one element. That element is divisible by $n$. Now, when it contains more than one element, the sum of such elements will also be divisible by n, since the individual numbers are divisible by n. I don’t think this is the right approach though. Any corrections and other methods will be appreciated. Edit: This approach is completely wrong, as is my previous understanding of the pigeonhole principle. Answers and a link to a similar question are in the comments.


In $\mathbb{R}$ with standard topology the closure of the above set $M$ is $M \cup 0$. I fail showing this by purely topological means. I.e. not using the fact that this holds in the reals as a metric space and deduce it for the induced topology.  I assumed that there exist a closed subset $A$ containing $M$ but not 0. Hence, the complement of $A$ is an open subset containing 0. Does this already yield a contradiction or do I need a different approach?  Could you help me on this?


In one of my answers here, I used the singular they:     When someone orders a rouge, they mean red wine which in French translates to le vin rouge.   My question is, is it right for me to use they? Or since I used someone at the beginning, is it imperative for me to use he or she?  Any insights?


Can metamagic be applied to a spell delivered by a familiar?

I have recently created a  (XGtE, p. 50) and plan on taking the  feat (PHB, p. 168) where my lvl 1 spell would be . Now as it states this familiar can be a focal point for your touch spells (like  for me).  Can I apply metamagic options to spells delivered through the familiar?  For example: My familiar is close to 2 of my allies. Can I at this point make it cast a twinned death ward to make both my allies warded?


I am making half adder circuit for my school project but I saw their datasheet and it says maximum supply volate is 5.25v and I have 9v battery, How do I use it if I want to test my circuit without burning ICS? I watched this video to complete my project but he didn't specify the battery he used. Pls help Video link -: . Thank you IC I used : Ic 7408(SN74LS08N) , IC 7432 (SN74LS32N), IC 7404 (SN74LS04N) . thank you


How can I make a command execute at startup?

I wanted to remap the keys for my page up and page down number pad so that they would actually act like the real page up and page down.  I used the xmodmap successfully following the directions based on the  help (plus some a tweak that I realized on my own).  I would like to make those two commands execute every time I start the computer:  xmodmap -e "keycode 89 = Next KP_3 Next KP_3" xmodmap -e "keycode 81 = Prior KP_9 Prior KP_9"   Sure, I can see that the proper way to remap the keys would be to create xinitrc and Xmodmap files, but I thought it would be a good time to learn how to make something happen at startup instead.  Also, I thought this would be easier to maintain since I would only have to keep track of the startup scripts rather than remember the xmodmap files.  Based on the instructions in  I thought I could add the commands to my /etc/rc.local file, but that's clearly not working.  Also, based on the directions in the , I tried adding the commands to ~/.bashrc and ~/.bash_profile.  This also didn't work.  Can anyone tell me what I'm missing?   Thank you


Every ideal is generated by two elements in $k[x^2, x^3]$

Let $k$ be a field, and consider the subring $k[x^2,x^3]$ of $k[x]$. Prove that every ideal in $k[x^2,x^3]$ can be generated by two elements.   What I have tried is: suppose $I$ is a nonzero ideal in $k[x^2,x^3]$; we may choose a polynomial with least degree to be one of the generators. But I have no idea about the next step.


which one is correct? Could we consider both somehow correct?   Using idioms and expressions is appreciated.   Or  Using idioms and expressions are appreciated.   Thanks a lot.


What's the name of each pseudo-rectangle in a spherical surface?

Consider the common surface of a  crossed with a . This produces a pseudo-rectangle in the sphere surface, and a perfect rectangle in a . What's the name of it? Does it have a special name? How do you think we should call it?


Combining two SELECT queries horizontally MySQL Workbench

I am trying to get the Team Name and Score of a game. Here are the tables: game (GameID, Team1, Team2, Team1Score, Team2Score, GameDate, StartTime) team (TeamID, TeamName, TeamType, ClubID) Team1 and Team2 are foreign keys to team.TeamID I am trying to get TeamName of Team1 and Team2 so I tried a UNION ALL statement, but I am getting this: TeamName Score I want a result like: TeamName Score TeamName Score SELECT t.TeamName, g.Team1Score AS Score FROM game g INNER JOIN team t ON t.TeamID = g.Team1 WHERE GameDate = '2015-10-04' AND StartTime = '10:00:00' UNION ALL SELECT t.TeamName, g.Team2Score AS Score FROM game g INNER JOIN team t ON t.TeamID = g.Team2 WHERE GameDate = '2015-10-04' AND StartTime = '10:00:00';  I want to combine these horizontally so TeamName Score TeamName Score (left 2 represent Team1 and right 2 represent Team 2). How do I go about doing this?


friends,  i am very new to ubuntu,and is been using this incredible thing from past few days, it's a really very new experience for me,i would like to know about one click install methods as like in windows we found .exe softwares every where, is there any method? and please do suggest me some awesome websites for repository's. Thanks


Print box drawing characters with pdfLaTeX

I need to print some unicode characters (of box drawing family) in my document. I found this  that is very similar to mine but is valid only for XeLaTeX. There is a valid way to do this with pdfLaTeX or I have to use XeLaTeX instead?


Find $\lim_{n\to \infty} \left( \prod_{i=1}^n \left( 1+ \frac{i^2}{n^2}\right)^i \right)^\frac{-1}{n^2}$

If $a_n = \left(1+\frac{1}{n^2}\right)\left(1+\frac{2^2}{n^2}\right)^2\left(1+\frac{3^2}{n^2}\right)^3\ldots\left(1+\frac{n^2}{n^2}\right)^n$ then find $\lim_{n\to \infty} a_n^\frac{-1}{n^2}$


How do I keep spellcasters from casting while in jail?

Interesting situation came up in my session. The players captured a wizard NPC and put him in jail. Then came a long discussion about what measures needed to be taken in order to prevent said wizard from using spells to force his way out.  Basic measures like removing a spell book, holy/arcane focus, and spell components would prevent use of any spells with a material component. A gag would stop verbal spells and being bound would stop somatic spells. However this is an unsustainable level of treatment for a jail for more than a day or so since it would have to be applied to ALL prisoners since there is no easy way to tell who can cast and who can't.  Preventing a long rest would severely handicap most casters in that it would prevent recovery of spell slots/sorcery points, although a warlock wouldn't be affected. Seems like a basic precaution to not allow prisoners long periods of rest. But this doesn't affect unused spell slots and no character class, from what I can tell, "loses" spells if they don't perform some sort of ritual each day (they just can't change their prepared spells if applicable), even the wizard. So unless a caster is tapped out on spell slots/sorcery points before being jailed, they would always retain what they have left even if denied a long rest (and would still have cantrips).  So, apart from being tightly bound, gagged, and stripped, are there any ways to prevent casting that I'm missing?  There are plenty of verbal only spells that would be useful in a jail environment (Command, Knock, Misty Step) so really, how are casters supposed to be locked up other than some sort of dedicated magicked prison (assuming you could even transport them there)? Just taking out the gag to feed them opens up the possibility of a spell being cast. I don't want my characters to have to be treated like this if they get jailed, but it seems like in a world of scarse magic items but numerous magic wielding people, anyone not KNOWN to be non-magic using would be treated like Hannibal Lecter or put in an Arkham Asylum type specialty prison (bad example, folks escape from there all the time! Maybe the one from Harry Potter).  My homebrew solution is to have the higher levels of exhaustion stop casting. This way someone who has been in a jail for more than a few days can't cast due to poor conditions, poor food, etc. But they can still move around a bit and talk, so there are role playing possibilities (barter for more food, become prison kingpin to get better treatment, bribe a guard, etc). When captured maybe casters could be bound and gagged, but it wouldn't be necessary for long term imprisonment.  I'm using the basic vanilla forgotten realms setting with the suggested "low magic item availability" from the 5e PHB and DMG. Judging from the published campaigns I've read (Phandelin and Horde) there does not seem to be common availability of magical effects and devices. Party level is 5-9th level.  The answers to the previous setting-free question  has plenty of useful "soft" suggestions like archers on the roof. But I would like some 5e and Forgotten Realms-specific techniques.


Why do C# multidimensional arrays not implement IEnumerable?

I have just noticed that a multidimensional array in C# does not implement IEnumerable<T>, while it does implement IEnumerable. For single-dimensional arrays, both IEnumerable<T> and IEnumerable are implemented.  Why this difference? If a multi-dimensional array is IEnumerable, surely it should also implement the generic version? I noticed this because I tried to use an extension method on a multidimensional array, which fails unless you use Cast<T> or similar; so I can definitely see the an argument for making multidimensional arrays implement IEnumerable<T>.  To clarify my question in code, I would expect the following code to print true four times, while it actually prints true, false, true, true:  int[] singleDimensionArray = new int[10]; int[,] multiDimensional = new int[10, 10];  Debug.WriteLine(singleDimensionArray is IEnumerable<int>); Debug.WriteLine(multiDimensional is IEnumerable<int>); Debug.WriteLine(singleDimensionArray is IEnumerable); Debug.WriteLine(multiDimensional is IEnumerable);


Firebase values may produce Java.land.NullPointerException when comparing

I am currently trying to check whether 2 values, saved in my Firebase database, are equal to or greater than the other. Although I'm having no problems getting the value's and creating a Toast which displays the correct values, when I put them in an 'if' statement, both value's come up 'null'. Is there any solution to this?  Here some code.   public void onDataChange(DataSnapshot dataSnapshot) {                                                if (dataSnapshot.child("endTime").exists()) {                                                        Long timeOpened = dataSnapshot.child("timeOpened").child("time").getValue(Long.class);           Long serviceEnd = dataSnapshot.child("endTime").child("time").getValue(Long.class);              Toast.makeText(StoryPreset.this, timeOpened + " " + serviceEnd, Toast.LENGTH_LONG).show();       if (timeOpened >= serviceEnd) {                                                                      Toast.makeText(StoryPreset.this, "Values are not null.", Toast.LENGTH_LONG).show();      } else {                                                                                Toast.makeText(StoryPreset.this, " they are null.", Toast.LENGTH_LONG).show();      }      As I mentioned, the 'Toast' present in the above code displays both values fine. It is only when they are put into an if statement that they become null. Any help is greatly appreciated!   EDIT: just to be more clear, inside the 'if' statement, bith 'timeOpened' and 'serviceEnd' are highlighted in yellow & when hovered over, a popup states that they may produce NullPointerExceptions. When testing, I also made sure I tested when I knrw 'timeOpened' was greater than 'serviceEnd' of which I got the result 'they are null'  EDIT: This question has been marked as a duplicate of the question "What is a NullPointerException". Just to be clear, I understand what a NullPointerException is and why it occurs, however I cannot understand as to why I cannot reference and compare values within the Firebase Database without them becoming NullPointerExceptions, and how I can compare them without having the NullPointerException result.


Given that $\frac{1}{a}+\frac{1}{b}+\frac{1}{c}=1$ show that:$$(a+1)(b+1)(c+1)\ge 64$$ My attempt: First I tried expanding the LHS getting that$$abc+ab+bc+ca+a+b+c \ge 63$$ I applied Cauchy-Schwarz on $(a+b+c)(\frac{1}{a}+\frac{1}{b}+\frac{1}{c})$ getting that $a+b+c\ge9$.  Then I also tried to manipulate the first condition and got $abc=ab+bc+ca$, then I applied AM-GM on $a+b+c$ getting the following$$a+b+c\ge3\sqrt[3]{abc}$$ Finally I substituted $ab+bc+ca=abc$ in my initial expression, getting:$$2abc+(a+b+c)\ge63$$The last thing I tought about was that I have both $a+b+c\ge9$ and $a+b+c\ge3\sqrt[3]{abc}$ so if I somehow related them I would have $\sqrt[3]{abc} \ge 3 \rightarrow abc\ge27$ and with this conditions the problem would follow by summing, but the direction of the inequality is not allowing me to do as intended...  I'm stuck here, have tried lot of other things but nothing really worked, also partial help is appreciated!


How do I dictate the destination folder of a clickOnce application?


How to analyze video card RAM and GPU load?

I would like to analyze my video card performance (RAM, load, etc) the way that top, free and lscpu does for my main hardware.  Is there an app to do this?


Game resource timers - general implementation

I'm interested in understanding how resource generation timers work on many of the mmorts type games out there. I can't wrap my head exactly around how the timers are synched with servers, especially with multiple users. If I need to provide more details, please let me know.  Thanks!


Can anyone explain the prime difference between doing something like:  <car>    <color>        Blue    </color> </car>  VERSUS  <car color="blue" />


Proof that $41$ does not divide $a^5 - 2$

How can i proof that $41$ does not divide $a^5 - 2$ for any $a \in \Bbb Z$? I think i must show that $a^5 - 2$ is multiple of 41. So if i do $(a^5 - 2) / 41$ i must get 0 rest? I'm stuck sorry. Thank you.


High CPU usage from "NT Kernel & System"

Not sure what is going on.  I have ran Process Explorer and I dont' see any of the usual culprits.  I have consistent 70-90% CPU usage.  It's often within the services process due to Windows Update. I typically just disable the windows update service and I'm good to go.  But over the last couple days, ntoskrnl.exe has been chewing away at my performance big time.  My computer starts slowing down more and more and more, and eventually practically comes to a halt.  Oddly enough, sometimes it will slow down to a grind even though the CPU usage only says it is at 50%.  A couple months ago I upgraded the RAM to 16GB, which seemed to help but now it seems whatever issue I am dealing with has finally caught back up.  I don't see anything particularly insightful to me within process explorer, and none of the help articles I googled are helpful.  Any tips?


Delete all backups of specific file/folder with tmutil

I'm trying to delete all backups of specific items through the command line. I can accomplish this using the GUI through the following steps:    Enter Time Machine    Navigate to the file to be deleted   Right click (or click the gear icon in the finder) and choose "Delete all backups of ..."   How can I replicate this on the command line using tmutil? Especially, when using Backup Loupe to detect large files it'd be easier to use the Terminal (since I don't have to enter TimeMachine at all each time I want to delete a particular file and can navigate to it using the Finder, and then drop it onto Terminal for a command to delete it).    I was hoping I could use something like this:  sudo tmutil delete /path/to/file   however it gives me the error:     "Invalid deletion target (error 22)"`   This works fine:  sudo tmutil delete /Volume/Backups.backupdb/<machinename>   and this too:  sudo tmutil delete /Volume/Backups.backupdb/<machinename>/<specificbackup>   According to man tmutil the delete command should also be able to delete specific items.  However, I've been out of luck so far. While there are numerous answers on this site (and elsewhere) to delete specific backups with tmutil and to delete specific backup items through the GUI (using the method described above) I was unable to find any non-GUI way to delete specific backup items.


Why do we put letters in some words which are silent in pronunciation? If they make no sound then why we waste space in words? For example:  "Knife"; 'K' is silent  "Doubt"; 'b' is silent etc.


How to root my android device without losing data?

I want to root my android device but I have a lot of personal data stored in it. It also doesn't have a micro sd card slot. So I was wondering if there is any way to root my device without losing any data and without using a PC?


How to extract a shapefile with a SQL expression from a database of shapefiles using PyQGIS or OGR

I have a shapefile Water_Districts.shp that consists of several water district polygons. I am trying to use the script below to 'extract' a specific polygon with the name Cache La Poudre River listed under the NAME column in the Water_Districts.shp attribute table. I have been using the python script below, but am not sure how to incorporate the SQL expression in the -where exception of the ogr2ogr command. I am getting the error: FAILURE: SetAttributeFilter(NAME = Cache La Poudre River) on layer'Water_Districts' failed.  import gdal import subprocess  directory = r"F:\IrrigatedLands\FC_test\Water_Districts\Water_Districts.shp" output_shp = r"F:\IrrigatedLands\FC_qgis\boundary.shp"  subprocess.call(["ogr2ogr", "-where", "NAME = Cache La Poudre River", output_shp, directory])


multiple Value of group of fields in CCK

I would like to create a form with CCK.  The user should be able to create unlimited number of "people" :   M    -  Smith   -   John Mrs  -  Dave    -   Lily M    -  John    -   Doe ...   So I need a Select (with gender) - textfield (last name) - textfield (first name).  I can not create each field to unlimited it would not be linked. I have tried field_group, but it does not give me the ability to put multiple value.  What would be the best way to do that ? I thought about create my own field with those 3 inputs. but it seems way to complicated for the simple thing I need to do. further more I cannot find any good tutorial.  EDIT : I'm using Drupal 7


I want to download and verify the ISO of lubuntu. The problem is I can't find a secure channel in the first place. The official ISO  is being downloaded with http (not https). Of course I can download and then verify the hash, but the only place I can find the hashes is , which is also insecure http. Any way to securely download the ISO?    Edit: The proposed duplicate question is not similar to my case - it talks about downloading using apt, which uses an authentication mechanism (no user action needed). My questions is about files downloaded manually, thus I must authenticate the files by myself.


How can I get the Nautilus file manger to open?

I've recently installed Ubuntu 16.04 and I cannot get Nautilus to open. Clicking on the icon does nothing and I've already tried un-installing and reinstalling it and the error persists. So I have tried to to launch it from the terminal and these error messages are returned:   (nautilus:27014): GLib-GIO-CRITICAL **: g_dbus_interface_skeleton_unexport: assertion 'interface_->priv->connections != NULL' failed (nautilus:27014): GLib-GIO-CRITICAL **: g_dbus_interface_skeleton_unexport: assertion 'interface_->priv->connections != NULL' failed Could not register the application: Timeout was reached (nautilus:27014): Gtk-CRITICAL **: gtk_icon_theme_get_for_screen: assertion 'GDK_IS_SCREEN (screen)' failed (nautilus:27014): GLib-GObject-WARNING **: invalid (NULL) pointer instance (nautilus:27014): GLib-GObject-CRITICAL **: g_signal_connect_object: assertion 'G_TYPE_CHECK_INSTANCE (instance)' failed   I'm not certain if I should just scrap nautilus for some other file manager or perhaps there is a solution to this problem?


I've brought 2 New controller and both do the same the white light flashes but will not turn on, I'm assuming they are holding power as they are both New and genuine and the light flashes.  I'm not a computer person and it probably something silly but would appreciate some advise for my son. Thanks in advance Gav


For $n \in \mathbb{N}$ and $W \leq \mathbb{F}^n$, there exists a homogeneous system of linear equations whose solution space is $W$

For $n \in \mathbb{N}$ and $W \leq \mathbb{F}^n$, show that there exists a homogeneous system of linear equations whose solution space is $W$.  Here's my work: Since $W \leq \mathbb{F}^n$, $k = dim(W) \leq dim(\mathbb{F}^n)$. Let's say that $\{w_1,w_2,...,w_k\}$ is a basis of $W$. Now, construct a matrix $A$ (of size $k \times n$) such that its rows are elements from the basis of $W$, stacked together. The row space of $A$ is $W$, so the row space of its row-echelon form is $W$ too. At this point, I'm stuck! I'm trying to come up with a homogeneous system with the help of $A$, though there may exist other easier ways of approaching this problem. Could someone show me the light? P.S. $W \leq \mathbb{F}^n$ stands for $W$ is a subspace of $\mathbb{F}^n$. P.P.S. Isn't this equivalent to saying that $W$ is the null-space of some matrix? Can we go ahead along these lines, and construct a matrix $P$ such that $Pw = 0$ for all $w \in W$?


Is there a way to bind an array to mysqli prepare

I'm trying to make a class that will execute any one of a number of stored procedures with any amount of variables  Im using php and mysqli   My class enumerates an array and constructs a string based on the number of elements if any giving something like this CALL spTestLogin(?,?) for example I now need to bind the input from my array using somethin like this:  $stmt->bind_param($this->paramTypes,$this->paramValues);//paramValues is my array   Then if that works I can work on getting my results  Any ideas


Can I make a dual port USB HUB without a controller (parallel connection) it is only going to be used for a mouse and a keyboard. In other words will the Pc recognize them as 2 devices. Thanks


Quora users (bots?) are copying a significant amount of Stack Exchange questions to Quora, without proper attribution. It seems quite systematic. Examples from :    :   Examples from :  :  :   I'm guessing that some other Stack Exchange websites are affected. I wonder whether Quora help organize this content theft because when looking at the profiles of the Quora "users" that copy all questions, such as  (he's the one copying https://money.stackexchange.com's questions) and  (he's the one copying https://travel.stackexchange.com's questions), we don't see the questions in the user profiles, which shouldn't be happening and therefore seems to be some kind of cover up only Quora could technically do, as far as I know. Anyway, how can we make this systematic content license infringement stop?  Updates:  2020-01-26: I reported Quora users  and  to Quora on 2020-01-20: Quora has taken no action yet and hasn't communicated with me. I have noticed that some questions posted on Stack Exchange get copied to Quora in less than one minute, which leads me to think that this copyright infringement process from Quora is automated. For example,  got copied to  by  in less than one minute. I've just reported this Jordan-Gambrell-2 user to Quora. If Quora doesn't take action within 1 week,  I will   via .  2020-01-29: I've looked at Quora's content more systematically over the past few days and it is clear that thousands of questions have been copied, and very likely one or two order(s) of magnitude more (I'm guessing >10k questions). Quora still hasn't replied to me.  As a result, I have  via .  2020-03-08: I haven't had any reply from Quora or Stack Exchange.  from a Stack Exchange employee:  [Stack Exchange] don't send any follow-up because we do nothing with about 99.9% of those reports.   2020-07-07: Further examples by Dex Jackson are documented at the Chinese.SE meta: .  It is possible to watch the plagiarism taking place live on . We can see on  that Steve is also actively plagiarizing questions from Stack Exchange.  2020-07-09: Further examples by Dex Jackson are documented at the Math.SE meta:  where there is a response from Quora; they (failing to see the irony) write:  Thank you for your report. It appears from your claim that you do not own the copyright of the and/or are not authorized to act on behalf of the owner. We ask that you provide more specific evidence that you own the copyright to the content in question, such as a copyright registration or other information supporting your claim.  Meanwhile,  continues.   So for now I'm simply double posting my questions on both Stack Exchange and Quora, which on the upside of makes it a bit easier to .


Php How to make a multidimensional array as a single string

array(array("Color", "red" ), array("Ram", "4GB" ) );  Convert this multidimensional array into a string like this Color=red&Ram=4GB


Are consecutive days counted each 24 hours or by UTC?

I'm pretty sure I've visited Stack Overflow and Meta Stack Overflow every day before 4 PM PDT (midnight UTC) for the past 50 days. I can recall seeing it say (I believe) 35(?) consecutive days visited a few weeks back. Then, all of a sudden, the counter reset on both sites. That got me wondering:  Say you visit at 6:30 UTC, would not visiting until 6:35 UTC the next day reset the counter, or do you just need to visit once every UTC day?


Normally one uses visudo to edit /etc/sudoers and perhaps add a line similar to this one kirk ALL=(spock) NOPASSWD: ALL  which will allow the kirk user to become spock. Question I need to create a non-interactive Bash script that will allow user1, user2, user3 to become spock. Does anyone knows how to do that?


Can you guys show me some different ways of using integration by parts to evaluate $\int \cos(\sqrt{x})\,dx$? I was trying with $u=\cos(\sqrt{x})$ and $dv=dx$, and it may have worked out eventually but things were getting messy. Maybe there's a substitution to be made before we assign $u,v$ to simple things. Thanks!


Use comparison test to show that $\sum^{+\infty}_{k=1} \frac{1}{k(k+1)(k+2)}$ converges and find its limit  I tried expanding out the denominator, and then using the comparison test with $\frac{1}{k^3}$ but I think this is an incorrect use of the comparison test as I get divergence. I know that the limit is $\frac{1}{4}$ but I am not sure how to use the comparison test to then apply the limit.


I've been trying to find out if this graph is planar or not for a while and have really been coming up short when it comes to creating a planar drawing of the graph. My intuition is telling me that it's non-planar, but I cannot find any subgraph of the graph homeomorphic to K3, 3 (by Kuratowski's Theorem). Any help would be greatly appreciated. The graph can be seen below:


Does using links to other pages dilute the linking page's link juice/page rank?

There are lot's of questions here about passing link juice to other pages, including .  I've read several of them over the months, but I always come away wondering the same question.  Does linking to another page, dilute or burn some of the link juice the linking page has already earned?  For example, if my current page has for example, a link juice of 10, and I link to another page, it passes a certain amount of juice (I'll use 90% as an example) of the linking page's juice, giving the page being linked to a .9 boost in it's own link juice.  However, does that mean the linking page's page's remaining juice is now less than 10?  While some of the questions would imply this to be the case, it seems counter intuitive as no one would ever want to link to any page outside of their own content for fear of losing page rank.


I would like to have two dryers in my laundry room. Can I run both off of the same circuit? Can the outlets be run in series? What upgrades do I need to make for this to work. I have room for another breaker in my box, which is in the same room. I am doing extensive work, including removing drywall, in the laundry room and now would be the time to make changes.  Thanks!


for some reason my mesh is only visible as a wireframe. I would like to get it back to a solid or textured view. Any suggestions?


How to make APFS option available in disk utility?

I want to reformat an external harddisk    For some reasons there is no option of APFS. How can I enbale APFS for an external harddisk?  Here is the detail of the external harddisk  My Passport 0837:    Product ID:   0x0837   Vendor ID:    0x1058  (Western Digital Technologies, Inc.)   Version:  10.72   Serial Number:    57999999414199999365659999   Speed:    Up to 5 Gb/sec   Manufacturer: Western Digital   Location ID:  0x01100000 / 1   Current Available (mA):   900   Current Required (mA):    896   Extra Operating Current (mA): 0   Media: My Passport 0837:   Capacity: 1 TB (1,000,170,586,112 bytes)   Removable Media:  No   BSD Name: disk4   Logical Unit: 0   Partition Map Type:   MBR (Master Boot Record)   USB Interface:    0   Volumes: Photo Backup 1 bad:   Capacity: 1 TB (1,000,169,537,536 bytes)   Available:    912.63 GB (912,629,383,168 bytes)   Writable: Yes   File System:  Case-Sensitive Journaled HFS+   BSD Name: disk4s1   Mount Point:  /Volumes/Photo Backup 1 bad   Content:  Apple_HFS   Volume UUID:  2254E6C8-8BB6-38B0-9153-D99C10A7B874


Save not Serializable Collection to the file

I have Collection with objects which I want to persist to the file:  private List< TestPart > testParts;   Class TestPart is extending Abstract class and two interfaces. Is it possible to write that kind of collection to the file? I tried to use jaxb/kryo - without effect.  Class TestPart is not implementing Serializable interface and I can't change it.  I should also mention that class TestPart has a references to the other not serializable classes.  Any ideas how to save data like this?  Thanks in advance.


The picture above shows what I am referring to. I'm looking for a way to change these " A, B, C, ..." labels to describe better the content below each.    A would contain what date, B  what length I run, etc.


Just me, a schizophrenic and a petty arsonist.   How many people are there in the above sentence? Is it ambiguous?


Brother/sister and two telepathic cat-like aliens crash land their spaceship in medieval Europe

Book was late 70's early 80's science fiction/fantasy. What I can remember was the main characters (four) were a brother and sister (who were either Human or almost-human) with a pair of telepathic (and very intelligent) Panther-like copilots. Their spaceship crash lands on Earth in medieval times Europe. (sometime in the early 1000's) At least one of the kids (I think the girl, but not sure) gets separated from the others and is taken by the local lord. The lord quickly realizes the kid has smarts and uses him or her to help defeat his enemies. I know this isn't much to go on, but can't remember a lot else about the plot. I'm sure it was written by one of the major writers of the age (Andre Norton, Piers Anthony, et al), but haven't been able to locate it. The cover of the book I had showed the two panthers kind of surrounding the 'window' looking out to the kid or kids and a castle. Books it isn't: The Barque Cats, Pet Cemetery, Pride of Chanur, Timecat, Cats of Ulthar, any of the Honorverse (Go Nimitz!), Tail Chaser or Master Ren. Also, this was a singular novel, not part of an anthology or series. At least I don't think there was ever a sequel written.


I have two monitors, but only one dock, which is somewhat annoying, so my question is, how do I get multiple docks? (One on each screen)


android@android:~$ sudo snap install skype error: This revision of snap "skype" was published using classic confinement and thus may perform        arbitrary system changes outside of the security sandbox that snaps are usually confined to,        which may put your system at risk.         If you understand and want to proceed repeat the command including --classic.   what does this mean? Could someone elaborate on this.


Blend Mode Alpha Clip Doesn't Show in Eevee Render

I'm following a Ducky3D tutorial  The alpha clip in the material settings is supposed to show an array of see through planes. Without the alpha clip, it's not see through. How do I get the alpha clip to render? No matter what the alpha clip won't show in an Eevee render. I don't want to use Cycles because it looks weird. Viewport display Vs Eevee below Viewport Display:  Eevee Render:  Cycles Render:


I think stackoverflow.com is great, and I would like to contribute. Usually, I find the answers to my questions are already there. I'd like to upvote the best answers and questions, but I do not have any reputation here. How do I get initial reputation?  The canonical way seems to ask a question. Which I hereby did.  Any other suggestions? I'd like to avoid stupid, pointless things (which I already failed to do by asking this question...).


Why is the Automorphism group of cyclic group of order of power eof 2 not just $Z 2^{n-1}$

I'm banging my head trying to figure out why the automorphism group of group of order $2^n$ not just the cyclic group of $2^{n-1}$, isn't the automorphism completely determined by where $e$ is sent to? in this case only the odd number are possible so it should just be $2^{n-1}$ right?


How to create an annotaded bibliography for unsrt bibliography style

How can I make an annotated bibliography using the unsrt style? I use the unsrt biliography style to create the reference list based on the order the references appear in the document.  I use a bibtex file that holds all the entries of my bibliography. I want to add an extra field to each entry with a short description which should then appear in the bibliography.  Current code:  \documentclass{article} \usepackage[utf8]{inputenc} \usepackage[margin=1.5in]{geometry} \title{The current state of cross-platform game development for different device     types} \author{...} \date{...}  \begin{document} \maketitle  \input{Preface.tex} \input{Abstract.tex} .... \bibliographystyle{unsrt} \bibliography{mybib} \end{document}   example entry of bibtex file:  @inproceedings{someref,  author = {....},  title = {....},  ....  publisher = {....},  AnnotationOrSomething = {blabla} }   I use sharelatex as editor.


Is it possible to install Ubuntu on a Chromebook? If so, what are the minimum system requirements? Will Ubuntu preform as well on the Chromebook as on a Windows laptop?


How to make CREATE OR REPLACE VIEW work in SQL Server?

CREATE OR REPLACE VIEW doesn't seem to work in SQL Server. So how do I port CREATE OR REPLACE VIEW to work on SQL Server?  This is what I'm trying to do:  CREATE OR REPLACE VIEW data_VVVV AS  SELECT      VCV.xxxx,         VCV.yyyy AS yyyy,         VCV.zzzz AS zzzz FROM  TABLE_A ;   Any ideas?


Why RSA must make sure that $\gcd(e,\varphi(n)) = 1$ instead of $\gcd(e,n) = 1$?

By Euler's theorem, if $\gcd(e,n) = 1$, then $e^{\varphi(n)} \equiv 1 \pmod n$. But why does RSA need to make sure that $\gcd(e,\varphi(n)) = 1$?


Bypass & Enable tether / WiFi hotspot on Android M (Marshmallow) Preview 3?

I just got a Nexus 6 and flashed Android M Preview 3 to it and also have it rooted, but how do I enable tethering / WiFi hotspot?  I tried doing the old method of finding dun_tether in the SQLite database, but it isn't there anymore.  How would one enable tethering / WiFi hotspot on Android M (Marshmallow)?


Proving the limit of a function of a sequence is equal to the function of the limit of that sequence

Suppose $f$ is a continuous function at $x = c$ in $[a,b]$.  Prove that for any sequence ${x_n}$ in $[a,b]$ converting to $c$, the sequence $\{f(x_n)\}$ converges to $f(c)$.  That is, $$ \lim_{n\to\infty}f(x_n)= f\left(\lim_{n\to\infty}x_n\right)$$    This proof seems simple but there are a few things that I need to know first. If $\{x_n\}$ converges to $c$, is it sufficient to substitute $c$ in for $\lim_{n\to\infty}x_n$?  Also needing some guidance on the structure of this proof.  Thanks!


Matrix Problem about commutative multiplication

The problem is:  "Find all $2\times 2$ matrices A that have the property that for any $2\times 2$ matrix  B, AB = BA."  Given hint: "The given equation must hold for all B. Try matrices B that have lots of zero entries."  I tried bashing by letting $A=\begin{pmatrix}a & b\\c & d\end{pmatrix}$ and $B=\begin{pmatrix}w & x\\y & z\end{pmatrix}$, but as you can tell, this got messy quickly. Any help would be appreciated, thank you.


Can I make windows open renamed zip files in explorer?

I have some files on my system (extension .sublime-package). These files are nothing but a .zip with a different file extension. I can currently browse them by renaming the file, then double clicking to open with the explorer zip viewer.  Is there something I can enter in the "open with" dialog to persuade windows to open the original files with its default zip viewer?


Is this proposition about polynomials obvious or not?

I am reading an algebra book now.       Let $p(x) \in \mathbb{R}[x]$ and $\deg p = n$.   Let $\alpha \in \mathbb{C} - \mathbb{R}$ and $p(\alpha) = 0$.        Then, $p(\bar{\alpha}) = \overline{p(\alpha)} = 0$.        So, $p(x)$ is divisible by $(x-\alpha)(x-\bar \alpha)$.        $(x-\alpha)(x-\bar \alpha) = x^2 - 2 \Re(\alpha) x + |\alpha|^2 \in \mathbb{R}[x]$.        So, there is a polynomial $q(x) \in \mathbb{R}[x]$ such that $p(x) = (x^2 - 2 \Re(\alpha) x + |\alpha|^2) q(x)$.     Why $q(x) \in \mathbb{R}[x]$?  Is it necessary to prove that $q(x) \in \mathbb{R}[x]$? Or, is it obvious that $q(x) \in \mathbb{R}[x]$?    My proof is here:    There is $q_1(x) \in \mathbb{C}[x]$ such that $p(x) = (x-\alpha)(x-\bar \alpha) q_1(x)$ in $\mathbb{C}[x]$. There is $q_2(x), r_2(x) \in \mathbb{R}[x]$ such that $p(x) = (x^2 - 2 \Re(\alpha) x + |\alpha|^2) q_2(x) + r_2(x)$ in $\mathbb{R}[x]$ and $2 > \deg r_2$. $p(x) = (x-\alpha)(x-\bar \alpha) q_1(x) = (x^2 - 2 \Re(\alpha) x + |\alpha|^2) q_2(x) + r_2(x)$ in $\mathbb{C}[x]$. By a theorem about long division, $q_1(x) = q_2(x), r_2(x) = 0$. So, $p(x) = (x^2 - 2 \Re(\alpha) x + |\alpha|^2) q_2(x)$, and $q_2(x) \in \mathbb{R}[x]$.


I have a Samsung Notebook NP900X4C with an LUKS encrypted installation on it. The system is booting in UEFI mode.  The problem is that the samsung-notebook kernel module is disabled in UEFI mode and due to that I am missing features like the keyboard backlight.  Is it possible to modify the current installation so it can boot in BIOS mode?  Is this correct that the basic steps would be converting the disk from GPT to MBR and installing grub from a live CD? Would this be possible with a LUKS partition?


i want to make a bootable usb with kubuntu 18.04 on it but every time i try this pop-up shows: "An error(1) occurred while executing syslinux. Your USB drive won’t be bootable."


Why is there no absolute maximum temperature?

If temperature makes particles vibrate faster, and movement is limited by the speed of light, then I would assume that temperature must be limited as well. Why is there no limit?


I'd like to test/run Ubuntu QML apps on the MIR Desktop preview that should be available with 14.04.   What are the steps needed to enable a native MIR desktop (preview) session?


Show that there are two, $a_i$ and $a_j$ with $i≠j,$ such that either $a_i+a_j$ or $a_i- a_j$ is divisible by $100.$

Suppose $(a_1,a_2,…,a_{52}$) are integers, not necessarily distinct. Show that there are two, $a_i$ and $a_j$ with $i≠j$, such that either $a_i+a_j$ or $a_i−a_j$ is divisible by $100$. Show that this is not necessarily true for integers $(a_1,a_2,…,a_{51}).$  If we divide $a_i$ by $100$, we get 99 possible remainders- hence we can get 52 distinct remainders on dividing each of 52 distinct $a_i$'s by 100. Can't proceed from here.


How to centralize an icon and a paragraph in one line

I'm trying to centralize an icon and a paragraph in the header of application. Currently it looks like this.    I want to show an icon and a paragraph with same height. I added padding-bottomto make it happen though it didn't work.   sample.js (The application is made with React.js )
SAMPLE TITLE
   index.css  .title { text-decoration: none; background-color: #454545; color: white; padding-bottom: 10px; }   Edit : This question was marked as duplicate with . I didn't know about vertical align and I think there is people like me, so I would like to keep this question.


C# Difference between get and set and manually written GetSomeValue() and SetSomeValue(value) methods?

I'm wondering if there is a difference between accessing private properties in C# through the automatic set and get properties and manually written GetSomeValue() methods.  Eg:  private int someValue { get; set; };   Vs.   public int GetSomeValue() {     return someValue; }