Why was I refused a Canadian visit visa?

Hi I'm a citizen of Mauritius. I applied to Canada for a temporary visa to see a friend who would give me accommodation for 1 month. To my surprise my visa was refused, for the following reasons:   Travel history: I don't understand this statement as I have been to Japan, Malaysia, Australia, Switzerland, France, England, Germany, Italy and Spain. Family ties in Canada and Mauritius: True for Canada as I'm visiting a friend; incorrect for Mauritius, as mentioned in my application that my dad and I live in the same house.  Reason for my visit: I said that it was for tourism. Finance: I said that I would bring $2000 for the month, and I would have free accommodation. However, the bank statement which I provided showed more than that amount. Job: I provided a letter from my employer, a international company, in which I'm a senior software engineer.   With all this, I don't understand the refusal. Can I do anything about it?


Compute ${n \choose 0}+2{n \choose 1}+3{n \choose 2} + \cdots + (n+1){n \choose n}$

I am having trouble doing this question and I do not know where to start. Any help is appreciated.


We are having an issue where we have 5 dinner tables which are available for booking. The problem we have is that these tables are very popular and the users who wish to book these tables all try to book at the same time and occasionally the same table is being assigned twice. What would be the best way(fullproof) to stop this from happening?  The code is below  $date="2015-05-01 19:00";   // LIST OF DINNER TABLES $fcas = array('Table 1','Table 2','Table 3','Table 4','Table 5');}   // FIND AVAILABLE DINNER TABLE $sql = "SELECT * FROM bookings WHERE   date_time='$ed' and table_assigned IN ('" . implode("','", $fcas) . "'))";   $rs = mysql_query($sql);  if (!$rs) {     // Handle query errors here }  $rows = array();  while ($row = mysql_fetch_array($rs)) {     $rows[$row['table_assigned']] = $row; }  foreach ($fcas as $fca) {     if (!isset($rows[$fca])) {         break;     } }   // INSERT RECORD  $sql_insert = "INSERT INTO bookings (date_time, table_assigned) VALUES ('".mysql_real_escape_string($date)."', '".mysql_real_escape_string($fca)."')";  if (!mysql_query($sql_insert)) {     die('Error: ' . mysql_error()); }


Why does not http call /usr/bin/http instead of /usr/local/bin/http?

Show my path: echo  $PATH /usr/local/bin:/usr/bin:/bin:/usr/local/games:/usr/games:/usr/lib/go/bin  Issue http command: http  --version bash: /usr/local/bin/http: No such file or directory  Where does http locate? which http /usr/bin/http  Issue http command with absolute path: /usr/bin/http  --version 0.9.8  Why does not http call /usr/bin/http instead of /usr/local/bin/http ?


Notification of voting activity on MSO posts

I use notifications in the "recent achivements" toolbar dropdown more to see whether people are upvoting/downvoting me than to see how much rep I'm going to get out of it.   Consequently, it's frustrating that voting activity on my Meta.SO answers, which of course imbue no rep, is not represented in this dropdown.  In fact, looking through my profile, I'm not sure whether it's possible at all to find out when people are disagreeing/agreeing with me.  Could we have some way to see this activity, please?  (Since all per-site metas have this repless feature, this is a global SE feature request.)


Why is proper time defined to be of opposite sign of the space time interval ds? Shouldnt it be exactly the space time interval?  My question was not about time having opposite sign it was about proper time for which I thought is the same as space time interval in the rest frame..but I realized that its not.


Resumable downloads when using PHP to send the file?

We are using a PHP scripting for tunnelling file downloads, since we don't want to expose the absolute path of downloadable file:  header("Content-Type: $ctype"); header("Content-Length: " . filesize($file)); header("Content-Disposition: attachment; filename=\"$fileName\""); readfile($file);   Unfortunately we noticed that downloads passed through this script can't be resumed by the end user.   Is there any way to support resumable downloads with such a PHP-based solution?


Number of new lines in a string as integer

I want to find the number of new lines in a string and then use this number in a while loop as the limit.  I can find and write the number of lines using:  echo "$MY_STRING" | grep -c '$'   In order to have the number of lines as integer and use it in while loop I do this:  MYNUM="$MY_PEERS" | grep -c '$'   However, this line writes 0, which is not the number of lines in my string, immediately to the terminal. Moreover, I cannot use MYNUM in a while loop. (I use $MYNUM in the while) How can I obtain number of lines so that I can use it in a while loop as the limit?


Is this actually how gravity is illustrated?

In general relativity, gravity is said to be caused by the curvature of space time.  And there are examples that illustrate gravity such as this video , and many pictures online.  But in these examples space time in essentially just a 2-D plane that sinks down when an object is placed on it.  I guess you could say that in these examples gravity is portrayed to be a literal potential well in space time.  Also, this is a man on Earth . This man could just jump off earth into space since he is above the potential well.  Shouldn't the proper illustrations have potential wells all around the object?


How to move file from Windows to Linux subsystem?

I have a tar.gz file downloaded in Windows and I want to move it to the linux subsystem directory. Is it safe to directly paste my files in the lxss folder?. Is it possible to do it safely?  System: Windows 10 along with Ubuntu subsystem terminal   I am aware that I can access Windows directories from linux subsystem terminal via /mnt/c I am also aware that editing files in linux subsystem directories using windows tools is dangerous


How to find answer to the sum of series $\sum_{n=1}^{\infty}\frac{n}{2^n} $

I have put his on wolfram and obtained answer as follows:  $\sum_{n=1}^{\infty}\frac{n}{2^n} = 2$  And the series is convergent too because $\lim_{n\to\infty} \frac {n}{2^n} = 0$  However I am wondering if there is a convenient way to solve this; I don't think you can represent it by a geometric progression either. So how do we have to do it on paper?


How to easily tell what package something is in without knowing its command-line name?

I have read this  and understand how to tell what package a certain command is in, however I still have a problem, how do I tell what package a program is in if I don't even know how to launch through command-line because I have no idea of its name (which is precisely the problem)?  So, to give an example, I recently wanted to file a bug report against the program known as "Software & Updates" in the GUI, however I had no idea what its name in the command-line was nor what package it was in. I tried running apt-file search "Software & Updates", but the results weren't very useful and I ended up having to ask around and finally found out it was in the software-properties-gtk package. Is there not another more efficient way of finding out what package something is in?    OS Information:  No LSB modules are available. Distributor ID: Ubuntu Description:    Ubuntu 15.04 Release:    15.04 Codename:   vivid Flavour: GNOME GNOME Version: 3.16


How to define a comma separated list of arguments for includegraphics

I have a large set of pictures, and I want to apply predefined settings to each using the optional argument of the \includegraphics macro from the graphicx package.  I would like to define the settings once at the top of the file (like \def\settings{width=\textwidth, angle=90}), and then apply them to all of my images so that I can modify all of the settings from one place.  If I run the following code block, it gives me the versions of the error "Package xkeyval Error: 'width=\textwidth, angle=90' undefined in families 'Gin'", which seems to be because it's interpreting my entire group of settings as a single key input.  \documentclass{article} \usepackage{graphix} \begin{document}      \def\settingsA{width=\textwidth, angle=90}     \def\settingsB{page=1, scale=.1}     \def\settingsC{angle=90, scale=.5}      \begin{figure}         \includegraphics[\settingsA]{filename1.png}         \label{fig:oneofonehundred}     \end{figure}      \begin{figure}         \includegraphics[\settingsB]{filename2.pdf}         \label{fig:twoofonehundred}     \end{figure}      \begin{figure}         \includegraphics[\settingsC]{filename3.jpg}         \label{fig:threeofonehundred}     \end{figure}   \end{document}   What is the technique to modify this settings string so that it is interpreted correctly? How do I pass an optional argument that is interpreted as a set of arguments instead of one string?  Thanks in advance!


Extension of Fermat's little theorem with Carmichael numbers

I'm a bit confused about the nature of one of my homework problems. It is requesting an explanation for why a congruence holds for $a^n \equiv a \;(\!\!\!\mod n)$ for a composite $n$, however this congruence is not always true from my understanding as having $a^n \not\equiv a \;(\!\!\!\mod n)$ provides that $n$ is not prime in the case that this occurs so the equivalence may not always be true. The question is however prefaced by the given $n$ being a Carmichael number though. Could anyone hint at how I should approach this explanation?  The Problem  The number 561 factors as $3 \cdot 11 \cdot 17$. First use Fermat's little theorem to prove that \begin{equation*} a^{561} \equiv a \;(\!\!\!\mod{3}), \quad  a^{561} \equiv a \;(\!\!\!\mod{11}), \quad  a^{561} \equiv a \;(\!\!\!\mod{17}) \end{equation*} for every value of $a$. Then explain why these three congruences imply that $a^{561}  \equiv a \;(\!\!\!\mod{561})$ for every value of $a$.  Current Solution  Fermat's little theorem states that given a prime $p$, for every $a\in(\mathbb{Z}/p\mathbb{Z})^{\ast}$, \begin{equation*} a^{p-1} \equiv 1 \;(\!\!\!\mod{p}). \end{equation*} Then by Fermat's little theorem, \begin{equation*} a^{561} = a^{2\cdot28}a = \big(a^{28}\big)^2a \equiv a \;(\!\!\!\mod{3}), \end{equation*} \begin{equation*} a^{561} = a^{56 \cdot 10}a = \big(a^{56}\big)^{10}a \equiv a \;(\!\!\!\mod{11}), \end{equation*} \begin{equation*} a^{561} = a^{35\cdot16}a = \big(a^{35}\big)^{16}a \equiv a \;(\!\!\!\mod{17}). \end{equation*}


How do I add a blank line between the footnote line and the footnotes?

Between the footnote line and the first footnote on that page, I need to add a double-space. I've tried using the \ command, but it adds a space after the number. Does anyone know a way for me to do this?


Existence of a closed and open set in 0-dimensional Hausdorff space

Given $T = 0-$dimensional (i.e, T has a basis of sets which are both open and closed), Lindelof Hausdorff space, with closed subsets $A$ and $B$ such that $A\cap B = \emptyset$. Prove that $\exists$ a closed and open set (clopen) set $D$ with $A\subset D$ and $B\cap D =\emptyset$.  I have thought of this problem for a while, but haven't been able to make any good progress. Can someone please give some detailed help, if possible, on this tricky problem?


Is this polynomial irreducible in $\mathbb{Q}$?

this is a really easy question but I cant find an answer;  In need to see if $x^4+x^2+x+1$ is an irreducible polynomial over $\mathbb{Q}$


when changing a defective fan I found out that because only 2 wire  cables were used, they have used the ground as the third wire to supply the light. Is this legal and safe? This is in a condo in Florida


If someone wanted to learn to speak Tolkien's Elvish languages ( and ) is there a guide to how to go about doing so?   Are there any authoritative sources regarding which language should be tackled first?


Prove that the eigenvalues of a skew-symmetric matrix are purely imaginary

Proof idea:  $A$ is a skew symmetric matrix.  $A$ is similar to $A^t$ because every matrix is similar to it's transpose. $$A^t = -A $$ $A$ is similar to $-A$. Let $P_{(\lambda)}$ be the characteristic polynomial. $$P_{(A)}=P_{(-A)}=0$$ (I'm not sure about the above step)  And I also know that:  $\overline{P_{(A)}}=\overline{P_{(-A)}}=\overline0=0$  That's where I ran out of ideas. am i in the right direction?


I am conducting research on photons and was wondering if they have relativistic mass. I already know that they they have zero rest mass. Any answers are welcome!


Find the remainder of a number with a large exponent

I have to find the remainder of $10^{115}$ divided by 7.   I was following the way my book did it in an example but then I got confused. So far I have, $\overline{10}^{115}$=$\overline{10}^{7*73+4}$=($\overline{10}^{7})^{73}$*$\overline{10}^4$ and that's where I'm stuck.   Also, I don't fully understand what it means to have a bar over a number.


Suddenly only 'snap' directory is visible in root

Suddenly, the only folder that I can see in /root is snap. Notwithstanding, the blog that I have installed on the website keeps working.  Output of ls -al /:


How do I change the interpolation of shape key animations?

I have a series of shape keys on a curve but the vertex interpolation between the morphing is no good. Is there a place in blender where I can view the animation paths of the vertices in the shape keys and fix up how the vertices interpolate so i can make it smoother.


Customs clearance for LCD monitor at Mumbai airport

I’m travelling from Muscat carrying a 32 inch Sony Bravia LCD. Would I have to pay duty on it? and how much amount of duty is allowed for a  passenger returning after 45 days?


Reputation change because of question deletion?

For example, I have an answer which is accepted by someone's question (i.e. reputation +15). Will this reputation be removed if the question is deleted by the user?


Attempt to invoke virtual method java.lang.String getTest_Series_name() on a null object reference. How i solve this error?


Infinite loop when prompting for user input?

I am in an intro to java class and have we have to create a Mine Sweeper game.  I have the game complete for the most part. But I have having 1 issue where my program goes into a crazy infinite loop.  When the user Guesses wrong and hits a "bomb", the game correctly ends.  But when they guess correctly and do not hit a bomb, the program enters a infinite loop for some reason and I have to terminate it.  I use 2 2dArrays, one  that displays to the player as all '?', and the other that has actual bombs placed on it, that I compare guesses to and update the player board.  I feel like the problem is in my GetGuess method.  Not sure why this infinite loop only happens the the user makes a correct guess.  The first guess prompt works fine, and if it hits a bomb, the game ends.  If the guess is good, the program should ask for another guess, but instead  The infinte loop prints:   Enter row number:  null   over and over again until I terminate.  Can anyone help me figure out where this is coming from?    Here is my main and Game class.  public class MineSweeper {  public static void main(String[] args) {      Game test = new Game();     test.loadBombs(test.bombBoard);     test.loadArray(test.board);     test.loadNumber(test.bombBoard);     test.displayBoard(test.board);     test.displayBoard(test.bombBoard);      while(test.gameOver==false)//Continue to get user guess until win or lose     {     test.getGuess(test.board, test.bombBoard);     test.displayBoard(test.board);     }  }   public class Game {  int arrayDimension = 9; char[][] board = new char[arrayDimension][arrayDimension]; char[][] bombBoard = new char[arrayDimension][arrayDimension]; static boolean gameOver;  public static void getGuess(char[][] boardArray,char[][]bombBoard) {       int rowGuess = 0, colGuess=0;     Scanner reader = new Scanner(System.in);        //Prompt user guess        boolean valid = false;//Check if guess is valid        while(valid == false)        {       try{        System.out.println("Enter row number: ");        rowGuess= reader.nextInt();         System.out.println("Enter column number: ");        colGuess = reader.nextInt();         if((rowGuess<0||rowGuess>8) && (colGuess<0||colGuess>8))//Check if guess is valid        {            throw new IndexOutOfBoundsException("This row and column is out of bounds!");        }        else if(rowGuess<0 || rowGuess >8)        {            throw new InputMismatchException("Invalid Row Choice!");        }        else if(colGuess<0 || colGuess >8)        {            throw new InputMismatchException("Invalid Column Choice!");        }        else{}        }        catch(Exception e)       { System.out.println(e.getMessage());       }         if(rowGuess >= 0 && rowGuess<=8) //Guess was valid, place * at location         {             if(colGuess >=0 && colGuess<=8)             {                 boardArray[rowGuess][colGuess]= '*';                                reader.close();                 valid = true;             }         }        }        char answer = bombBoard[rowGuess][colGuess];//check bomb board with user guess        if(answer == '#')//Bomb, you lose        {            boardArray[rowGuess][colGuess]= answer;            System.out.println("You hit a bomb, game over!");           gameOver = true;               }        else//correct guess, Place number of bombs around guess, continue guessing.        {            boardArray[rowGuess][colGuess]= answer;           gameOver = false;        }  }


This may seem like a very basic question, but:  What exactly is the difference between a root of a polynomial, and a zero?  Of course I realise that they are technically exactly the same thing, but there seem to be subtle rules as to when to use each term, and a couple of times in the past I have been told I am using "root" where I should be using "zero".  Is it generally accepted that one should use "root" in an algebraic context,  and "zero" in a analytic context? If not, when should one use one or the other...and does it really matter?!


Which relative pronoun is correct and why?

There are 2 statements. I am not sure which one is right.  Who does this pen belong to?  To whom does this pen belong?  Please explain both according to British grammar especially according to relative pronoun?


What certification do you need to sell electronic device to US market?

Other than FCC and RoHS statement, what other certifications do you need to have in order to sell your product to US Market?  My device is a remote control using Bluetooth Module. Operate using 4 x AA battery .  The Bluetooth module is already certified with CE and FCC.  I was told I may need a Safety test. ETL if I'm not mistaken.


$ uname -a Linux msi 5.8.14-arch1-1 #1 SMP PREEMPT Wed, 07 Oct 2020 23:59:46 +0000 x86_64 GN>  so I do a console login as a regular user, type reboot and it works. shutdown now as well. Why am I not required to be root to do that like on debian?


Congruence for the sums of odd powers of integers

Does someone know how to prove ***EDIT by induction**** that for all integers $n\ge1$, $k\gt0$  $$\sum\limits_{i=1}^{n} {i^{2k+1}}\equiv 0\  \ \  \pmod{\frac{n(n+1)}{2}}$$  I thought this should be a quick outcome from known polynomial expressions for sums of powers, or easy by induction. But I have not been able to write down such a proof.  Thanks for help..  I make the above EDIT to 'deduplicate' (somehow) the question.    This is where I am:   Let $P_{m+1}$ be the $m+1$ degree polynomial such that $P_{m+1}(n) =\sum\limits_{i=1}^{n} {i^{m}}$  From  $$(n+\frac{1}{2})^{m+1}-(\frac{1}{2})^{m+1}=\sum\limits_{i=1}^{n}((i+\frac{1}{2})^{m+1}-(i-\frac{1}{2})^{m+1})$$ after expansion of the binomes on the RHS and rearrangement: $$(n+\frac{1}{2})^{m+1}-(\frac{1}{2})^{m+1}=\sum\limits_{j=0}^{m+1}\frac{\binom{m+1}{j}}{2^{j}}(1-(-1)^j)P_{m+2-j}(n)$$ I obtain a recurrence relationship for the $P_{2k}$ of even degrees $$2^{2k+2}(2k+2)P_{2k+2}(n)=(2n+1)^{2k+2}-1-\sum\limits_{j=1}^{k}2^{2j}\binom{2k+2}{2j-1}P_{2j}(n)$$ that is  $$2^{2k}(k+1)P_{2k+2}(n)=\binom{n+1}{2}\sum\limits_{j=0}^{k}(2n+1)^{2j}-\sum\limits_{j=1}^{k}2^{2j-3}\binom{2k+2}{2j-1}P_{2j}(n)$$ Now if I suppose that, for all $1\le j \le k$, for all $n$, all the $P_{2j}(n)\equiv 0\  \  \pmod{\frac{n(n+1)}{2}}$ , which is true for $j=1$, and since all the $2^{2j-3}\binom{2k+2}{2j-1}$ are integers even when $j=1$,  then I have $$2^{2k}(k+1)P_{2k+2}(n)\equiv 0 \pmod{\frac{n(n+1)}{2}}$$ which is almost (but not quite :-() enough to complete the proof by induction


Cell phone? Cell? Mobile phone? What's the "correct" term?

What's that type of phone called that you don't need a cable for and you can use everywhere in the world (provided there's coverage ;-))?  And what differences are there between the regions?  USA/UK/AUS etc... and even within, say, the US (or even UK).  I've even read rumors that in parts of the east of the US, people use the term "handy" (which is a really crazy German "Americanism").  EDIT: Clarification: The colloquial usage is more interesting (to me) than the "correct" official terminology (though that's of interest, too).


myOpenID shuts down February 1, 2014; add an alternative login method to your account

Janrain has , one of the many OpenID providers. MyOpenID will not be available starting February 1, 2014. (An   hinted at the same but did not set a date for end of service.)   This decision was made by Janrain, and Stack Exchange did not have any part in it. You can still use myOpenID to log in to Stack Exchange, but be aware that any outages in the myOpenID service will mean that you are unable to log in to Stack Exchange until Janrain fixes it – which may take several days, or weeks, or never. After February 1, you will no longer be able to use myOpenID to log in to Stack Exchange. Stack Exchange will not be able to answer any questions about why myOpenID is down or when it will be working again. If you do not have any other login credentials on your account by February 1, you will be locked out, and Stack Exchange will be unlikely to help you recover your account.  To avoid getting locked out of your Stack Exchange account, we strongly suggest that anyone using myOpenID as their primary (or even backup) login add a new login method to their Stack Exchange account.  We're also going to remove the "myOpenID" button from the sign-up/login page soon, in order to discourage new users from signing up using myOpenID.  Here's how to add a new login to your account. You must be logged into your account when you begin. (This information is also available .)  Open up your user profile page (by clicking on your login name at the top of the screen) and click the "my logins" link above the bio box on the right hand side.   You should see a list of all of your logins.  To add a new login, click "add more logins..." at the bottom of the box. Choose the new login from the list and follow the steps to confirm.    If you choose, you can remove your myOpenID login by clicking the same "my logins" link, then clicking "remove" next to myOpenID.  If you are adding a Stack Exchange OpenID, you will receive a confirmation email. You must click the link in the email to confirm your email address before the Stack Exchange OpenID will show up under "my logins". Please make sure that you are already logged into your account when you click the confirmation link; otherwise, you will create a new account that needs to be merged with your old one.    If you encounter any trouble adding logins, or accidentally create a separate account that you would like merged, please fill out our .


How to unload kernel module 'nvidia-Modeset'

I'm trying to install the most up-to-date NVIDIA driver in Debian Stretch. I've downloaded NVIDIA-Linux-x86_64-390.48.run from here, but when I try to do.  sudo sh ./NVIDIA-Linux-x86_64-390.48.run   as suggested, an error message appears.  ERROR: An NVIDIA kernel module 'nvidia-modeset' appears to already be loaded in your kernel. This may be because it is in use (for example, by an X server, a CUDA program, or the NVIDIA Persistence Daemon), but this may also happen if your kernel was configured without support for module unloading. Please be sure to exit any programs that may be using the GPU(s) before attempting to upgrade your driver. If no GPU-based programs are running, you know that your kernel supports module unloading, and you still receive this message, then an error may have occured that has corrupted an NVIDIA kernel module's usage count, for which the simplest remedy is to reboot your computer.   Any help to finish the installation nvidia drivers?


Java program boolean values defaulting to false, no idea why?

I wrote a program for school, which is supposed to ask for the day of the week, whether or not it is vacation, and then print out whether the user can sleep in. However, the Boolean values, sleepInDay(which decides whether it is a weekday or not) and sleepInDayV (which decides whether or not it is a vacation) both automatically change to false, even when I change their default values to true at the beginning of the code.   import java.io.*;  class main { public static void main(String[] args) { // TODO Auto-generated method stub try{     InputStreamReader istream = new InputStreamReader(System.in);     BufferedReader bufRead = new BufferedReader (istream);      boolean sleepInDay;     boolean sleepInDayV;      System.out.println("Please enter the day of the day"  );     String dayOfTheWeek = bufRead.readLine();      if (dayOfTheWeek == "Sunday") {        sleepInDay = true;     } else if (dayOfTheWeek == "Saturday") {        sleepInDay = true;     } else {        sleepInDay = false;     }      System.out.println("Is it vacation?"  );     String Vacation = bufRead.readLine();      if (Vacation == "Yes") {        sleepInDayV = true;     } else {        sleepInDayV = false;     };     System.out.println(sleepInDay + " " + sleepInDayV);      if ( sleepInDay == true || sleepInDayV == true) {         System.out.println("You get to sleep in!");     } else {         System.out.println("GET UP!");     } } catch(IOException err) {     System.out.println("Error reading line");{ }   Thanks for the help,  Kitten Taco


If we compare these two sentences:        I just done   I just finished      The first one doesn't make sense I think while the second one does. However, if we were to remove just, then:        I done   I finished      Both would seem to make sense? I think. Why is this the case?  Let's take an example sentence:        I just done dinner   I just finished dinner      Done and finished are both verbs but why can't done be used in the same way as finished?


Using change of variable technique to show uniform distribution

Problem:Let X have a logistic distribution with PDF $f_X(x)=\frac{e^{-x}}{(1+e^{-x})^2}$, $-\infty<x<\infty$. Show $Y=\frac{1}{1+e^{-X}}$ has an uniform distribution over (0,1).  Answer:$f_Y(y)=\frac{1}{|u'(x)|} f_X(x)=\frac{(1+e^{-x})^2}{e^{-x}} \frac{e^{-x}}{(1+e^{-x})^2}$=1 which is a constant. Hence it is an uniform distribution.  I am wondering there is another approach, which is the CDF technique. Does it work here too?


Someone said, group instances are rendered faster, so I've decided to replace actual bolt objects with group instances. Though, my model turned into a hairy mess, that I can't see through. Yes, it disappears, when you turn active "Only Render", but I need to work with it!


Is it ok to use an alternate account while my main user is restricted?

I'm new to Stack Exchange, and my main user only has 16+ rep. And it's been blocked in Code Review. I need to use Code Review today. Should I use an alternate account?


Variety that is affine and projective is a finite number of points

I was trying to proof the following without any luck. I would appreciate good hints.  A projective variety that is isomorphic to an affine variety is a finite number of points.


Why do faces appear transparent when exported to a game engine?

I created a low poly tree, and it's what I see in the editor:    But, in my 3D game engine (Godot Engine), this is how the tree looks:    (On the left, this is an icosphere created with Blender).  I don't know what part I missed, or what I done wrong for having this result with the 3D engine.  I started with a simple cube, cutting it and extruded it for this result, and I created manually near all the faces (except for the trunk). Then I exported the object in the Wavefront format (.obj).  Is my method wrong? Need I to recreate the whole object? How can I fix it?


I am considering applying the Service Pack 3 in a SQL Server 2008 with Service Pack 1; however, I was not able to find if there are any drawbacks in this process, specially regarding to Replication Services and Reporting Services.   Has someone done this kind of update? Was it smooth or did it generate many issues?


Why didn't Starfleet ever check on Khan?

Starfleet... never bothered to check on our progress   -Khan, Star Trek II, the Wrath of Khan  I understand that the odds of the neighboring planet exploding and causing the other planet to shift into its orbit in such a way as to utterly destroy the climate on said neighbor is very very low. But it seems rather irresponsible to me not to at least pay them a visit.   At the end of Space Seed, it seems that this was a legitimate Federation punitive measure (given Kirk et al busted out the fancy uniforms) which to me made it seem like the Federation was somewhat obligated to ensure they didn't die down there.   What gives? Why didn't Starfleet, at the very least, do a drive by? (In canon, please)


I am looking at  website, and it says "therefore we will need to determine the values of $\lambda$ for which we get, $$\det(A-\lambda I) = 0."$$ Now I am a newbie to linear algebra, and I have looked at several other sources, but I still can't understand why $\det(A-\lambda I) = 0.$ I already understand why $(A-\lambda I)\vec{v} = 0.$Can anyone help me with this?


Which version of Ubuntu is suitable for my Intel Atom N2600 processor?

I have a laptop, its configuration is as follows:  Processor: Intel Atom N2600 (1.6 Ghz, 1 MB cache) memory: 1 GB HDD: 320 GB   Which version of Ubuntu is suitable for this PC?


Enabling/Installing/Downloading Portal for ArcGIS?

How can I install Portal for ArcGIS?  I have installed ArcGIS for server 10.1 on linux.   I read in ArcNews that .   How can I enable it?


How do we validate emails in cloudpages?

I am creating a two cloud pages. One cloud page has one email input field and two input submit fields, one for Ok and one for Cancel. When the user writes their email address in the input field, I want to run validation onClick of the OK button. I created a javascript function within my cloud page and called it on my OK button. For some reason, my validation isn't being called successfully. I tested email addresses without "@", ".", and without both "a" and ".". When I click the OK button, it redirects me to the next cloudpage where people can sign up for different event communications. How can I validate email correctly? My code: <script runat="server">       function checkEmail() {         var email = document.getElementById('txtEmail');         var filter = /^([a-zA-Z0-9_\.\-])+\@(([a-zA-Z0-9\-])+\.)+([a-zA-Z0-9]{2,4)+$/;         if (!filter.test(email.value)) {           alert('Please provide a valid email address');           email.focus;           return false;         }       }     </script>  Email Input <input type="txtEmail" name="Email" value="%%emailaddr%%" data-field-type="Email" required="required" data-validation-message="Please provide your email address.">  OK Button  <input type="submit" value="OK" onClick="checkEmail();">


How to make new commands for function operations that don't italicize

I created new commands for Galois groups and Automorphism groups like so,  \newcommand{\Gal}[1]{\text{Gal}(#1)} \newcommand{\Aut}[1]{\text{Aut}(#1)}   I wanted to the text of Gal and Aut to be unitalicized and that works for normal math mode, but it italicizes in theorem environments. How can I keep it from italicizing in theorems and propositions?   An example of a function that does what I want would be the gcd function.


I'm new to photography and got my new  for my DX camera D5300.  I've taken first Portrait photoshoot of my friend in an outdoor park which looked nice on my camera screen. But when I move it to my computer, I could see the images were not sharp. I was inspired by many people's Portrait images with 50mm which thought I could replicate the same. But I assume I'm making some mistakes which can't identify myself.  I've taken various images of a subject with distinct settings and attached for your reference. Please advise me: what am I doing wrong?  Some info:   I used a tripod All images are cropped 100% Distance from subject to camera: 2 meters no post-processing   You can see the grain on all images. Please help


Find the value of $\lim_{n\to \infty } \,\cos (1) \cos \left(\frac{1}{2}\right) \cos \left(\frac{1}{4}\right)\cdots \cos \left(\frac{1}{2^n}\right)$

$$\lim_{n\to \infty } \,\cos (1) \cos \left(\frac{1}{2}\right) \cos \left(\frac{1}{4}\right)\cdots \cos \left(\frac{1}{2^n}\right)$$  How would you evaluate this limit? Is it just equivalent to $$\prod_{n=0}^\infty {\cos \left( \frac{1}{2^{n}} \right)}$$


How can I use a separate transformer to provide a C wire to my thermostat?

Update 02/02/2019 I appreciate all the responses and help but unfortunately i must have not seen the emails stating there were responses! I am now looking into a NEST thermostat and was curious if they too, use the same connections. Lastly, looking for a quick recommendation on which WiFi Compatible therms are preferred by the memebers that respond! Thanks again your knowledge is highly appreciated! Bob  I Purchased the Honeywell WiFi Prog Thermostat to replace my Round Digital Honeywell Thermostat. I have separate Heating and Cooling (Heating is a Weil McLain Boiler for Hot water baseboard and Hot water(no tank) and Cooling is a separate unit that was added later.)  Wires:  RC Cool R Heat W Heat Y Cool G Cool   3 wires from AC unit and 2 from Heater.  If I were to go the separate transformer route to power the thermostat, where would I land the 2 wires?  C and ???


increase the ADC resolution using oversampling

To increase the ADC resolution, oversampling technique can be used which must be followed by decimation (average) method. Oversampling is just take several samples within time period. Unlike the normal averaging in which you might lose all the extra bits from oversampling, Decimation can remove only the lowest of low bits leaving some of the higher low bit to contribute to final result.  What is the lowest and higher low bit? And why the lowest low bit usually most noisy than the rest of the bits?  From my understanding is that the higher the extra bit can we get, a better ADC resolution can we have. In this case why can't we just use oversampling without decimation? For example, a summation of 16 10-bit ADC result in 14-bit ADC and when we use decimation method (divide by 4) result in 12-bit resolution.   So why can't we just use oversampling and gain 14-bit resolution instead of 12-bit resolution with decimation? Is that  to reduce the noise after the oversampling stage?


Flash is installed but all flash embeds are replaced with blue i information icon. And I am using a web browser called  that supports flash. Is a windows update by microsoft blocking the flash player from running? Why is this happening?


I received the error message: The package system is broken and I am not, to my knowledge, using third party repositories. Following some of the recent posts on similar topics, I looked at other posts with similar issues and tried: sudo apt-get -f install  Results:  Reading package lists... Done Building dependency tree        Reading state information... Done Correcting dependencies... Done The following extra packages will be installed:   linux-image-3.11.0-19-generic Suggested packages:   fdutils linux-lts-saucy-doc-3.11.0 linux-lts-saucy-source-3.11.0   linux-lts-saucy-tools The following NEW packages will be installed   linux-image-3.11.0-19-generic 0 to upgrade, 1 to newly install, 0 to remove and 28 not to upgrade. 2 not fully installed or removed. Need to get 0 B/57.3 MB of archives. After this operation, 154 MB of additional disk space will be used. Do you want to continue [Y/n]?    Indicated Yes  Results:  (Reading database ... 171297 files and directories currently installed.) Unpacking linux-image-3.11.0-19-generic (from .../linux-image-3.11.0-19-generic_3.11.0-19.33~precise1_i386.deb) ... This kernel does not support a non-PAE CPU. dpkg: error processing /var/cache/apt/archives/linux-image-3.11.0-19-generic_3.11.0-19.33~precise1_i386.deb (--unpack):  subprocess new pre-installation script returned error exit status 1 Examining /etc/kernel/postrm.d . run-parts: executing /etc/kernel/postrm.d/initramfs-tools 3.11.0-19-generic /boot/vmlinuz-3.11.0-19-generic run-parts: executing /etc/kernel/postrm.d/zz-update-grub 3.11.0-19-generic /boot/vmlinuz-3.11.0-19-generic Errors were encountered while processing:  /var/cache/apt/archives/linux-image-3.11.0-19-generic_3.11.0-19.33~precise1_i386.deb E: Sub-process /usr/bin/dpkg returned an error code (1)   I have absolutely no idea what to do next.


Inline underlined spaces are getting out of margins

When trying to use underlined blank spaces for a questionary inside a book, I'm getting the underline out of document margings. Does anyone knows how to make underline command respect the document margins?  Code:  \documentclass[11pt]{elegantbook} \usepackage[spanish]{babel} \usepackage[utf8]{inputenc} \usepackage{soul} % Underlined spaces command \newcommand{\uline}[1]{\underline{\hspace{#1}}}  \title{Document Title} \subtitle{Subtitle}   \begin{document}  \maketitle  \frontmatter  \mainmatter  \chapter*{Introduction}  \Large  \begin{enumerate}   \item Test text test text test text test text. Test text test text test text test text test text. Test text test text test text test text. Test text test text test text test text test text.   \item Test text \uline{4cm} test \uline{4cm} test text test text test text test text.   % The following line is the one that is not respecting margins   \item Test \uline{4cm} test text test text test text test text \uline{5cm} test text test text test text. \end{enumerate}  \end{document}   Output:


Prove if $|z| < 1$ and  $ |w| < 1$, then $|1-zw^*| \neq 0$ and $| {{z-w} \over {1-zw^*}}| < 1$Given that $|1-zw^*|^2 - |z-w|^2 = (1-|z|^2)(1-|w|^2)$I think the first part can be proven by saying $|1-zw^*| = 0$ if and only if $zw^*$ = 1.  And given the conditions that cannot be true. However I don't know if this part is right.


Proving Combination identity by reasoning

By suitably interpreting each side show that $${k\choose  k}+{{k+1}\choose k}+{{k+2}\choose k}+...+{{n-1}\choose k}+{n\choose  k}={{n+1}\choose{k+1}}$$   This is easily shown by induction, but I think the questin is asking (and regardless I would like to know) what is the 'reason' for this, i.e. can we justify this result by considering subsets the way we can for results like ${n\choose r}+{n\choose{r+1}}={{n+1}\choose{r+1}}?$  I was surprised that I was unable to find this results on the internet although I'm almost certain it's out there so apologies if this need not be posted here.  Thank you.


Reinstalling Ubuntu 16.04 LTS on existing drive partition

I am currently dual booted with Windows 10 and Ubuntu 16.04 LTS, I had provided ubuntu with a petty 70 gbs and alloted the remaining storage of my 500 gb(i.e around 420 gbs in three partitions) HDD to windows 10, but recently I have been using ubuntu alot, now I think 70 gb is quite small for the usage I have.  So I want to reinstall ubuntu by taking 1 partitions from windows and merging it existing ubuntu partition and then reinstalling. In that way I won't be losing my windows data.  Is there anything I need to take care of before proceeding to this, as I recall I might encounter a problem which will disable my access to windows  into boot/grub menu or vice versa.  How do I avoid such instances?


How can I fix a geoTiff with an incorrect CRS?

Trying to load and plot a raster (it's a DEM) in R, but having problems.    Using R I read in a raster file:  library(raster)  dem <- raster("DEM_Victoria.tif")  # >70 MB print(dem)  class       : RasterLayer  band        : 1  (of  3  bands) dimensions  : 5444, 6007, 32702108  (nrow, ncol, ncell) resolution  : 100, 100  (x, y) extent      : 176615.6, 777315.6, 5650397, 6194797  (xmin, xmax, ymin, ymax) coord. ref. : +proj=longlat +ellps=WGS84 +no_defs  data source : DEM_Victoria.tif names       : DEM_Victoria values      : 0, 255  (min, max)   My confusion here is the extent vs the CRS. The extent shows coordinates from a UTM Zone 55S system, while the CRS reports it as longlat.   Similarly, gdalinfo reports:  Driver: GTiff/GeoTIFF Files:  DEM_Victoria.tif Size is 6007, 5444 Coordinate System is: GEOGCS["GDA94",     DATUM["unknown",         SPHEROID["unretrievable - using WGS84",6378137,298.257223563]],     PRIMEM["Greenwich",0],     UNIT["degree",0.0174532925199433]] Origin = (176615.587999997427687,6194797.138000000268221) Pixel Size = (100.000000000000000,-100.000000000000000) Metadata:   AREA_OR_POINT=Area Image Structure Metadata:   COMPRESSION=LZW   INTERLEAVE=BAND Corner Coordinates: Upper Left  (  176615.588, 6194797.138) (Invalid angle,Invalid angle) Lower Left  (  176615.588, 5650397.138) (Invalid angle,Invalid angle) Upper Right (  777315.588, 6194797.138) (Invalid angle,Invalid angle) Lower Right (  777315.588, 5650397.138) (Invalid angle,Invalid angle) Center      (  476965.588, 5922597.138) (Invalid angle,Invalid angle) Band 1 Block=6007x1 Type=Byte, ColorInterp=Red Band 2 Block=6007x1 Type=Byte, ColorInterp=Green Band 3 Block=6007x1 Type=Byte, ColorInterp=Blue   Is this real? A problem? (well it is to me, but perhaps because I don't understand something) Fixable?  I tried 'Assign projection' in QGIS, which uses this command:  gdalwarp -t_srs EPSG:28355 -srcnodata -32768  DEM_Victoria.tif DEM_Victoria.tif.tmp   but it failed with:     ERROR 1: Too many points (12100 out of 12100) failed to transform,   unable to compute output bounds.


What 70s (60s?) TV show / TV movie had a generation ship whose inhabitants did not know they were on a spaceship?

I have the vaguest memory of a TV show (maybe a BBC import?) in which the protagonists were moving through the sections of a massive generation ship whose inhabitants had forgotten that they were on a spaceship... I know there was an RPG with the same plot (which, after all, is a pretty great blank slate) but I definitely feel I saw this on a static-filled 13" B&W TV back in the day...


Flagging to close shows counter next to "flag"

If I (as a user with vote-to-close privileges) click "flag" on a question, I see the ability to flag as "does not belong here, or is a duplicate".  Is this a ? I'm quite sure I didn't used to be able to see that.   Anyway, if I use that ("does not belong here, or is a duplicate") option and VtC the question, take a sip of my tea and continue about my daily business, upon submitting the "flag", the counter for the "flag" button gets set, not the "close" button.   This would seem like a definite .


Just wanting to know what a Dirty Read is. If anyone could sum it up shortly and briefly that'd help. Looked online and nothing is really clicking to me. Appreciate the help, thanks.  Can you also give a simple clear example? Thank You.


How prove this series $\sum_{n=1}^{\infty}\frac{e^n\cdot n!}{n^n}$ divergent

Show that this series $$\sum_{n=1}^{\infty}\dfrac{e^n\cdot n!}{n^n}$$ is divergent. My try: since $$u_{n}=\dfrac{e^n\cdot n!}{n^n},\Longrightarrow \dfrac{u_{n+1}}{u_{n}}=\dfrac{e^{n+1}\cdot(n+1)!}{(n+1)^{n+1}}\cdot\dfrac{n^n}{e^n\cdot n!}=\dfrac{e}{\left(1+\dfrac{1}{n}\right)^n}$$ then $$\lim_{n\to\infty}\dfrac{u_{n+1}}{u_{n}}=\lim_{n\to\infty}\dfrac{e}{\left(1+\dfrac{1}{n}\right)^n}=1$$ so this limit is $1$, therefore I can't prove it by using the Ratio test.   From sos440 suggestion: by using Stirling's approximation, we have $$\dfrac{e^n\cdot n!}{n^n}\approx \sqrt{2n\pi}\to\infty.$$  Maybe this problem requires other methods.


Balls are taken one by one out of an urn containing $w$ white and $b$ black balls until the first white ball is drawn. Prove that the expectation of the number of black balls preceding the first white ball is $\frac {b}{w+1}$  Attempt: Let $X_i$ be the random variable that denotes the number of black balls that are drawn at the $i_{th}$ step before a white ball is drawn.  Then, the total number of such balls $ X= X_1 +  \cdots+X_n \implies E(X)=\sum E(X_i).$  $E(X_i)= 1 \cdot \dfrac {^bC_r}{^{b+w}Cr}\cdot \dfrac {^wC_1}{^{b+w-r}C_1}$  Thus, $\sum E(X_i) = \sum_{i=1}^{b} ~ 1 \cdot \dfrac {^bC_r}{^{b+w}Cr}\cdot \dfrac {^wC_1}{^{b+w-r}C_1}$  Could someone please tell me if I attempted this correctly? Because I get a very complicated answer in the end after evaluating the above.  Thanks a lot!


Collecting the origin directory of a Bash script from itself

Is there a way that a bash script detects the path directory in which it's running?  It is like if the script is aware of where is it. In order to use files that are in the same location as the script. I'd like to change the directory to where the Bash Script is.  This Bash script is used to trigger few actions (other python scripts, apps... etc.) but I want to switch the operation directory to his root one.


Continuity of a function to the integers

I am trying to prove that in $\mathbb{Z}$ with co-finite topology the only path-connected components are the singletons.  (I reckon that) showing that      "if a function $\gamma : [0,1] \to \mathbb{Z}$, where $\mathbb{Z}$ has   co-finite topology, is continuous then it is constant"   should do the trick.  However I am not sure this is true, let alone if this is a good approach to the problem. Any thoughts about it?  Edit: I was thinking: suppose $x,y \in \mathbb{Z}$ and $\gamma : [0,1] \to \mathbb{Z}$, where $\mathbb{Z}$ has co-finite topology. Further suppose $x \neq y$, then $f^{1}(\mathbb{Z}\setminus \{x\})=(0,1]$ which is not open in $[0,1]$, contradicting continuity. Hence $x=y$. Does it seem right?  Edit 2:  Forget the (stupid) edit above!


Prove that the natural map $\alpha : \text{Hom}(X,\text{Spec} A) \rightarrow \text{Hom}(A,\Gamma(X,\mathcal{O}_X))$ is an isomorphism

This is question 2.4 in Hartshorne. Let $A$ be a ring and $(X,\mathcal{O}_X)$ a scheme. We have the associated map of sheaves $f^\#: \mathcal{O}_{\text{Spec } A} \rightarrow f_* \mathcal{O}_X$. Taking global sections  we obtain a homomorphism $A \rightarrow \Gamma(X,\mathcal{O}_X)$. Thus there is a natural map $\alpha : \text{Hom}(X,\text{Spec} A) \rightarrow \text{Hom}(A,\Gamma(X,\mathcal{O}_X))$. Show $\alpha$ is bijective.  I figure we need to start off with the fact that we can cover $X$ with affine open $U_i$, and that a homomorphism $A \rightarrow \Gamma(X,\mathcal{O}_X)$ induces a morphism of schemes from each $U_i$ to $\text{Spec} A$ and some how glue them together. But I have no idea how to show that the induced morphisms agree on intersections. How does this work?


How many $5$-digit numbers with distinct digits are divisible by 3 (and generalize)

I'm solving a problem which asks me to find how many 5-digit numbers with distinct digits are there which are also divisible by $3$. I am familiar that there are $9\cdot9\cdot8\cdot7\cdot6=27216$ five-digit numbers with distinct digits. I know that a natural number $n$ is divisible by $3$ iff the digits sum up to a number divisible by $3$. Now, brute-forcing by a computer algorithm, i found that the result is $20928$. However, I am interested, if there is a mathematical solution for this. I know how to find amount of numbers divisible by $4$ or $5$. We just fix some amount on the last two (or last one) digit. But criterion for divisibility by $3$ is very different from those and I have no idea how to start. Eventually, I would like to find a general formula for $n$-digit numbers.  Edit: Equivallently we want to find how many solution does the equation $a+b+c+d+e=3k$ for $a,b,c,d,e\in\{0,1,2,...,9\}$, $a\neq 0$ also $a,b,c,d,e$ are all distinct and $k\in\mathbb{Z}$ (the highest possible $k$ is in this case $k=11$, the smallest being $k=5$)  Edit (2): According to the ideas from the answer. Make $A=\{0,3,6,9\},B=\{1,4,7\}, C=\{2,5,8\}$. Let's go through the cases that in the number $n$ there are $0,1,2,3,4$ digits from $A$.  i) Suppose none of $A$ is in $n$. We can't form a number divisible by three. We have to take 5 numbers, that is $3$ from $A$ and $2$ from $B$ or $2$ from $A$ and $3$ from $B$. None of the expressions $3(3k+1)+2(3k+2)$ and $2(3k+1)+3(3k+2)$ are divisible by three.  ii) Let $1$ digit from $A$ be in $n$. The amount of ways to choose the digit is $5$. Now we are left to choose $4$ digits. The only possible way is to choose $2$ from $A$ and $2$ from $B$. The amount of ways to do this is ${3\choose 2}^2=9$ which together gives $5\times 9$ ways which can be permuted and alltogether $5\times 9\times 5!=5400$ possible ways.  iii) Let $2$ digits from $A$ be in $n$. The amount of ways to choose the digit is ${5\choose 2}=10$. We are left with $3$ digits. Either all of them are from $A$ or all of them are from $B$. That's $2$ possible ways and all together $20$ possible ways which we permute to obtain $20\times 5!=2400$ possible ways.  iv) Let $3$ digits from $A$ be in $n$. The amount of ways to choose the digits from $A$ is ${5\choose 3}=10$. We are to choose $2$ digits. We must take exactly one from $B$ and exactly one from $C$. The amount of ways to do this is ${3\choose 1}^2=9$. Alltogether $9\times 10$ possible ways which we permute to get $90\cdot5!=10800$ possible ways  v) In the last case where all four digits from $A$ are present, there is no way how to make the number divisible by $3$.  Summing this all up gives $5400+2400+10800=18600$ which is less than what my algorithm yielded. We also have to subtract these which begin with $0$. Can anyone spot the mistake? (If i did any?)


TexMaker: How to "save" user defined tags.

So I want to type commands like \geq_{\alpha} or \leq_{\alpha} into the user section (the bit with the symbol of the person, above PStricks, and below Left/Right).   Fine, but how do I save these commands? I closed texmaker and when I started again, the commands were all gone. It seems dumb to keep typing them in again and again and again.


A lot of missing dependencies when I try to install all software

I have problem with missing dependencies, when I try to install some software by apt-get and also from downloaded .deb files.  I am using Debian 10. After installation I removed a lot of software which I no needed eg. Deluge, some terminals (I have only LXTerminal now), some tools from Libre Office Packet etc.  Now, when I try to install Atom, TeamViewer, or some RDP tools, every time I got information about missing unresolved dependencies, common it is libgconf, libcurl etc.  How can I resolve this issue? Now I can not install a lot of must have software, and when I try to apt-get install this packets, I got error, that no libs with this name were found.  Here is my sources.list. Maybe it will be some tip to fix this problem:  deb http://security.debian.org/debian-security/ buster/updates non-free contrib main deb-src  deb-src http://security.debian.org/debian-security/ buster/updates non-free contrib main deb-src   deb http://deb.debian.org/debian/ buster-backports main contrib non-free  deb-src http://deb.debian.org/debian/ buster-backports non-free contrib main   deb http://ftp.de.debian.org/debian stretch main contrib non-free deb-src http://ftp.de.debian.org/debian stretch main contrib non-free   Stretch repos were added for test purposes, but when I comment them, it looks the same.


Bash - No such file or directory, even though the directory exists and the previous commands run correctly

I am running a very simple bash script on Macosx Yosemite  #!/bin/bash makefilePath=$(echo $(pwd)/make.sh | sed 's/ /\\ /') echo $makefilePath source "$makefilePath"   The first three lines work as expected, but the fourth line creates a returns an error No such file or directory, even though if I run the command from makefile directly in the shell by copy pasting it, it works fine.   I don't know what the problem is. Please help.


I am trying to implement a simple Quiz Game and when overriding toString method in my Question class I got a NullReferenceException. Where the problem comes from? This is my code in Question class      public class Question {         private String text;         private Answer[] answers;         private final static int ANSWER_SIZE_ARRAY = 4;          public Question(String text, Answer[] answers) {           this.text = text;           answers = new Answer[ANSWER_SIZE_ARRAY];           this.answers = answers;         }          public void setText(String text) {         this.text = text;      }       public void setAnswers(Answer[] answers) {           this.answers = answers;      }       public String getText() {          return this.text;      }       public Answer[] getAnswers() {          return this.answers;      }      //test toString     public String toString() {          String result = this.getText() + "\n";          for (Answer a : this.answers) {              result += a.getText() + "\n"; // HERE COMES THE PROBLEM          }          return result;      }   }   And my main method is like:      public class MainGameTestMethod {       public static void main(String[] args) {         Answer a1 = new Answer("Krisko", true);         Answer a2 = new Answer("Beatz", false);         Answer a3 = new Answer("Ivan", false);         Answer a4 = new Answer("Pesho", false);         Question q1 = new Question("Whats your name?", new Answer[] { a1, a2, a3, a4 });         System.out.println(q1.toString());     } }


2 Months old MacBook Pro (Mid 2020) battery only last for 4 hours

I'm new to the world of Apple, I bought a new Macbook Pro, mid-2020, Intel i7, 16GB RAM. I'm a developer, I run apps like VS Code, Sublime Text, Slack, Chrome (Multiple Windows), I play videos/songs in the background. I have been keeping a track of the energy consumption on my Mac, and it only runs for 4 hours. I have reset my SMC after I upgraded to Big Sur. Is 4 hours normal? or should I go to the service center? Update on 3 Feb 2021: I submitted my Mac to the Apple service center they said they conducted a few tests and the conclusion was that the battery is fine (I don't know what type of test they did). So I guess I'll be using it on AC Update on 12 Feb 2021: Took it to the service center, they didn't find any issues so I started using Safari for work and my battery has improved by 1 hour on Average.


Rephrase Neural Network: Where to Start?

I'd like to solve the problem that denoted in the below picture.    With which network could I try and start to solve this problem?


Like    Star    Is there any science between liking or staring? Does the user click one faster? Does the user respect one more?  Do users like or star?  EDIT: This question has been marked as a duplicate for a question that asked how different using a heart and a star button are. True, this shares the same concept, but not the same situation and set of parameters as my question, which asks about liking and a star button. Is liking the same as using a star?


Why did the big bang explode if there is no oxygen in space?

If there is no oxygen in space, where the super dense singular object was suspended, then why did it explode because this reaction needs oxygen?


I would like using Java to get data from Windows about CPU, RAM, HDD, Network and list of processes(services). How I can get these system values values without using third-party libraries or JNI?  Is there something similar to /proc in Windows where I can get all necessary values and use them?


howto fool the partition manager: problem : My /boot partition hit 100% and now I can't upgrade. Can't remove old kernels to make room

Well this question is asked often - however the solution seems not be so clear and does not really work for me.  $ df Filesystem               1k-blocks      Used  Available  Use% Mounted on /dev/sda5                   184307    173269          0  100% /boot /dev/sda6                  4673664   2926312    1486900   67% /home   $ dpkg -l | tail -n +6 | grep -E 'linux-image-[0-9]+' | grep -Fv $(uname -r)  pi  linux-image-4.4.0-21-generic                    4.4.0-21.37                                amd64        Linux kernel image for version 4.4.0 on 64 bit x86 SMP ii  linux-image-4.4.0-22-generic                    4.4.0-22.40                                amd64        Linux kernel image for version 4.4.0 on 64 bit x86 SMP iF  linux-image-4.4.0-28-generic                    4.4.0-28.47                                amd64        Linux kernel image for version 4.4.0 on 64 bit x86 SMP iF  linux-image-4.4.0-31-generic                    4.4.0-31.50                                amd64        Linux kernel image for version 4.4.0 on 64 bit x86 SMP   And this is the best one:  $ sudo apt-get purge linux-image-extra-4.4.0-36-generic  Paketlisten werden gelesen... Fertig Abhängigkeitsbaum wird aufgebaut.        Statusinformationen werden eingelesen.... Fertig Probieren Sie »apt-get -f install«, um dies zu korrigieren: Die folgenden Pakete haben unerfüllte Abhängigkeiten:  linux-image-extra-4.4.0-34-generic : Hängt ab von: linux-image-4.4.0-34-generic soll aber nicht installiert werden  linux-image-generic : Hängt ab von: linux-image-4.4.0-36-generic soll aber nicht installiert werden                        Hängt ab von: linux-image-extra-4.4.0-36-generic soll aber nicht installiert werden E: Unerfüllte Abhängigkeiten. Versuchen Sie »apt-get -f install« ohne Angabe eines Pakets (oder geben Sie eine Lösung an)   Somehow the 4.4.0-36 seems to be installed but it isn't. I even cannot brainwash the package manager.  I know I SHALL NOT cd /boot;rm -f ........ in order to confuse the masterbrain not even more but I see no other way then to help itself to get clean.   My question now is the following:  Can I sudo rm -f /boot/somebigfiles;sudo touch /boot/somebigfiles in order to create some working space on /boot?  How to fool the package manager so he thinks the stuff is installed and can clean itself with all the nice apt-get clean/autoclean and other apt commands?


How do you turn on and off window repaint while drag moving/re-sizing window in Windows 7?  When I drag a window or resize it, I just get a wireframe.  Some how this feature has gotten turned off.  thanks


In supervised learning, how to get info from correlation?

I am trying to build a classification model so I have tried to check the correlation between the features.    Here Loan_Status is my target variable.   I just don't know how to extract information from this? Please help. I have questions like. Is -0.0047 corelation of ApplicantIncome with Loan Status useful?


Little number for reviews available, but I've used up my 20/day

Okay, so today I burnt out all of my 20 reviews per day on all of the categories (except Late Answers).  Then I go back to my answering work.  And then I notice that the little orange number in the corner for reviews that are available for me to do has a "6" on it.  And I am excited that I will be able to reach my 20 review limit in all the categories.  But when I click on it, to my dismay, it was telling me that these "available" reviews are not available because they are in a category that I have already done my limit!  So, shouldn't the number next to the review button not show me the numbers for the review categories that are no longer available to me?  It's just holding them in front of my face saying "Look at all the reviews that you can't do!".  Is there a reason that this isn't changed?


Changing colour of text and background of terminal?

I can change the colour through preference , but how can I change the background colour and text colour of terminal through the command line?


What occurs in atomic scale that cause the photon to be reflected? In other words, what is the reason for photons to change its direction and why material can reflect certain wavelengths and absorb the rest? What are the atomic properties that causes that behaviour?


Can't boot into Ubuntu in Windows 10 / Ubuntu dual boot

I installed Ubuntu on a Dell XPS 13 laptop that had Windows 10 preinstalled on it. I installed it from a USB flash drive on a partition. When I boot my computer I can only boot into Windows 10 and Ubuntu is nowhere to be seen.  If I boot into my USB then I can see that Ubuntu is installed, but I can't get to it from the BIOS boot menu.


Need to identitify a short story about an astronaut stranded alone on a planet that houses a strange museum

Can anyone offer any help with this..? I read it at school around 1976 but cannot remember the title nor the author. Thank you in advance!  A lone astronaut called - I think- Steve is stranded on a distant planet when his ship runs low on fuel.   His only companion is - again I think - a parrot. The fuel his ship uses is a filament or wire which is kept on a spool.   On exploring the locale he has landed in he discovers a huge building half-buried in a mountainside. He enters the building and discovers it is a museum filled with thousands of glass cases containing preserved specimens of various life forms as well as machines.   There is a robot curator that does repairs and, as the astronaut finds out, prepares cases for new exhibits.   On analysing the wire in one of the machines he discovers that is suitable as fuel for his ship so he winds a length of it onto his ships spool and leaves the planet just ahead of the robot collecting him and his parrot as museum exhibits...


Help me understand the proof for Bolzano-Weierstrass Theorem!

The proof is from the book Advanced Calculus: An Introduction to Linear Analysis by Leonard F. Richardson  Theorem (Bolzano-Weierstrass): Let $x_n$ be any bounded sequence of real numbers, so that there exists $M \in \mathbb{R}$ such that $|x_n|\leq M$ for all $n$. Then there exists a convergent subsequence $x_{n_k}$ of $x_n$. That is, there exists a subsequence $x_{n_k}$ that converges to some $L \in [-M,M]$.  Proof: We will use the method of interval-halving introduced previously to prove the existence of least upper bounds. Let $a_1=-M$ and $b_1=M$. So $x_n \in [a_1,b_1]$, for all $n \in \mathbb{N}$. Let $x_{n_1}=x_1$. Now divide $[a_1,b_1]$ in half using $\frac{a_1+b_1}{2}=0$.     i. If there exist $\infty$-many values of $n$ such that $x_n \in [a_1,0]$, then let $a_2=a_1$ and $b_2=0$.      ii. But if there do not exist $\infty$-many such terms in $[a_1,0]$,   then there exist $\infty$-many such terms in $[0,b_1]$. In that case,   let $a_2=0$ and $b_2=b_1$.   Now, since there exist $\infty$-many terms of $x_n$ in $[a_2,b_2]$, pick any $n_2>n_1$ such that $x_{n_2} \in [a_2,b_2]$ in half and pick one of the halves $[a_3,b_3]$ having $\infty$-many terms of $x_n$ in it. Then pick $n_3>n_2$ such that $x_{n_3} \in [a_3,b_3]$. Observe that  $$|b_k-a_k|=\frac{2M}{2^{k-1}} \rightarrow 0$$  as $k \rightarrow \infty$. So if $\epsilon > 0$, there exists $K$ such that $k \geq K$ implies $|b_k-a_k|< \epsilon$. Thus if $j$ and $k \geq K$, we have $|x_{n_j}-x_{n_k}|<\epsilon$ as well. Hence, $x_{n_k}$ is a Cauchy sequence and must converge. Since $[-M,M]$ is a closed interval, we know from a previous exercise that $x_{n_k} \rightarrow L$ as $k\rightarrow \infty$ for some $L \in [-M,M]$.      $\blacksquare$  I boxed the part I didn't understand. I don't understand how we know which interval has $\infty$-many values of n for $x_n$ to be in that interval. Take $(-1)^n$ for example, I feel like both intervals $[-1,0]$ and $[0,1]$ have $\infty$-many values of $n$ such that $x_n$ are in the intervals, i.e., $1 \in [0,1]$ and $-1 \in [-1,0]$. Aren't both even numbers and odd numbers of $n$ be infinitely many in $\mathbb{N}$? Since $\mathbb{N}$ is $\infty$-many, how can we extract one set with $\infty$-many and another with finitely many numbers? I just can't convince myself to accept this part.


I have a form that is dynamically generated, and has dynamically generated id's (and potentially classes). The forms are the same but they have the related id tacked on to the end.  How can I select each set of inputs and apply code to each one?  I was experimenting with $('input[id^=@id_airline_for_]') but could not get it to fly. I suspect I am missing some fundamental jQuery knowledge that is holding me back since I am sure this is a common problem with dynamic forms.   <form method='POST'>     Airline:     <input id="id_airline_for_8" class="arrival_transfer_toggle_8" type="text" maxlength="30" name="airline_for_8"/>     Flight Number:     <input id="id_flight_number_for_8" class="arrival_transfer_toggle_8" type="text" maxlength="30" name="flight_number_for_8"/>      Airline:     <input id="id_airline_for_17" class="arrival_transfer_toggle_17" type="text" maxlength="30" name="airline_for_17"/>     Flight Number:     <input id="id_flight_number_for_17" class="arrival_transfer_toggle_17" type="text" maxlength="30" name="flight_number_for_17"/>      -- snip --  </form>   EDIT: I should update that i want to be able to perform some action when the input is clicked but only for classes with a matching id at the end.  To make it easy, lets say I want all inputs with a matching id at the end of the #id to disappear when one is clicked (just for arguments sake).


Sequence and Series: Find the sum of series

$f(r)=1+\frac{1}{2}+\frac{1}{3}....+\frac{1}{r}$ and $f(0)=0$, then value of $$\sum_{r=1}^n(2r+1)f(r)$$  (A) $n^2f(n)$  (B) $(n+1)^2f(n+1)-\frac{n^2+3n+2}{2}$  (C) $(n+1)^2f(n)-\frac{n^2+n+1}{2}$  (D)$(n+1)^2f(n)$  I googled and found that $1+\frac{1}{2}+\frac{1}{3}....+\frac{1}{r}$ cannot be  exactly calculated (but approximations exist, but the answer is not from approximations) so there has to be some way to reduce $$\sum_{r=1}^n(2r+1)f(r)$$ into solvable form, but I cannot figure out how, how to get the answer. The answer given is B.


How to upgrade Ubuntu LTS version to normal one?

I am currently running Ubuntu 20.04.2 LTS. I would like to update to the normal version of Ubuntu 21.04. I changed the last line of the file /etc/update-manager/release-upgrades from Prompt=lts to Prompt=normal but sudo apt update & upgrade still does nothing - it says everything is up to date. Thank you for any help.


External monitors show blank screen until restart

MacBook Pro (15-inch, 2016) with 2 USB-C to HDMI adapters. The setup works great if I start up in that configuration.   If I connect the adapters while the machine is running or simply sleeping, one of the monitors will never get a signal and stay in low power mode. The OS sees the monitor, it shows in the display arrangement settings and I can move the mouse into it, but until I restart, I can't see anything on it.  Once I have restarted I can let the machine sleep or whatever, and the display still works unless I disconnect the adapter. As soon as I do that a restart is required to use it again.   Using MacOS Sierra (10.12.4)  Using this adapter:


I am using multibib with two bib-files. For the first one I use a numeric citation style. But for the second one I want to have [A1, A2, ...]. This works for my reference list but in my citation I still have [1, 2, ...]. How can I change this to [A1, A2,...]?  Here is my minimal document (you have to use 2 bibfiles: litA and litB)  \documentclass[a4paper,10pt,twoside,titlepage,parskip=half-]{scrartcl} \usepackage[latin1]{inputenc} \usepackage[T1]{fontenc} \usepackage[ngerman, english]{babel} \usepackage{eso-pic} \usepackage{textcomp} %\textmu einfügen z.B. \usepackage[normalem]{ulem}     %text unterstreichen, durchstreichen usw. \usepackage[resetlabels]{multibib} \newcites{lita}{References1} \newcites{ownb}{References2} %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%  \begin{document} \makeatletter\renewcommand{\@biblabel}[1]{[#1]}\makeatother \bibliographystylelita{plain} \bibliographylita{./literature/litA}                    \citelitd{label1}  \makeatletter\renewcommand{\@biblabel}[1]{[A\,#1]}\makeatother \bibliographystylelitb{plain} \bibliographylitb{./literature/litB}                   \end{document}


Which repository will Ubuntu choose to download a package from if the same package is available in more than one repos? Suppose a package A was initially installed from repository X and later I added repo Y which also has package A. Which repo will be chosen to update the package? Also if I completely remove this package and try to reinstall then which repo would be preferred by Ubuntu to install the package?


In $b^a = x$, $b$ is the base, a is the exponent and $x$ is the result of the operation. But in its logarithm counterpart, $\log_{b}(x) = a$, $b$ is still the base, and $a$ is now the result. What is $x$ called here? The exponent?


How to remove title and other metadata from video files?

I have problem sorting videos in VLC because it is using the metadata title to sort them, but they all have the same title. Which is why I want to remove all metadata, especially titles.  How can I achieve this easiest and safest? I have over 2000 video files to process and I dont want to break them in the process.  The video files are in format .avi, .mp4, .mkv, .wmv, and more.


In hearthstone, you receive one quest per day, barring unique quests. What I'm wondering is when exactly does a new day start? I assume it's at a specific global time, so I'm looking for a time in GMT or UTC.  I did find out you need to exit the game and come back to receive new quests, but I'm hoping someone actually knows when i have to do that.


Group cohomology is one thing I don't seem to get my head around.  I understand $H^0$ as being the "fixed points" but when it comes to anything higher I have no idea what the notions are meant to be capturing...if anything.  For example I can see that 1-cocycles are homomorphisms with a specific property but that property doesn't seem to mean anything to me...and I think it should!  Is there an intuition or example that explains the meaning or is it just something that "stuck" and seems to work in lots of places?


I recently got new laptop (Dell XPS 15 9560) and I've bee having this issue where blender will crash when I try to select cycles as the render engine. I've tried reinstalling and rolling back my nvidia and integrated GPU drivers multiple times. Any suggestions or workarounds? I'm taking a course in blender later this year and I need my laptop for it. Thanks.


Why is $1 - \frac{1}{1 - \frac{1}{1 - \ldots}}$ not real?

So we all know that the continued fraction containing all $1$s...  $$ x = 1 + \frac{1}{1 + \frac{1}{1 + \ldots}} $$  yields the golden ratio $x = \phi$, which can easily be proven by rewriting it as $x = 1 + \dfrac{1}{x}$, solving the resulting quadratic equation and assuming that a continued fraction that only contains additions will give a positive number.  Now, a friend asked me what would happen if we replaced all additions with subtractions:  $$ x = 1 - \frac{1}{1 - \frac{1}{1 - \ldots}} $$  I thought "oh cool, I know how to solve this...":  \begin{align} x &= 1 - \frac{1}{x} \\ x^2 - x + 1 &= 0 \end{align}  And voila, I get...  $$ x \in \{e^{i\pi/3}, e^{-i\pi/3} \} $$  Ummm... why does a continued fraction containing only $1$s, subtraction and division result in one of two complex (as opposed to real) numbers?  (I have a feeling this is something like the $\sum_i (-1)^i$ thing, that the infinite continued fraction isn't well-defined unless we can express it as the limit of a converging series, because the truncated fractions $1 - \frac{1}{1-1}$ etc. aren't well-defined, but I thought I'd ask for a well-founded answer. Even if this is the case, do the two complex numbers have any "meaning"?)


My son is writing an essay about a dead hero. Most of the verb tense he used is in the PAST, as in, "He was a clever hero." To be consistent, he wrote, "He was an inspiring hero." However, it got me thinking if it would be better to say, "He is an inspiring hero," because he still continues to inspire others even after his death.


Redirect pop-up to wonderlandsads.com malware for webbrowsers

My PC has been infected with a malware that opens pop-up to some ads, mostly in my native language (Persian) but from (wonderlandads.com), when I click on a link or in an input box in StackExchange websites. Interestingly, it just occurs for these websites and no other website! It occurs in both Firefox and IE  I scanned my computer with NOD32 7.0.2 , and some freeware malware scanner (kaspersky tools,...), but they couldn't find it. I reinstalled the Firefox and disabled startups but couldn't fix it.  What is the cause? and what can I do?   How it can hide itself from powerful antiviruses and anti-malware?  ==============  Update It seems I could handle it by killing running processes and refreshing the firefox.


I am trying to create an Appendix for my experiment figures, and the following is the my code \section{}\label{sec:figures}  \begin{figure*}[h]     \begin{minipage}{0.75\textwidth}           ...     \end{minipage}       \end{figure*}  \begin{figure*}[h]     \begin{minipage}{0.75\textwidth}           ...     \end{minipage}       \end{figure*}  \begin{figure*}[h]     \begin{minipage}{0.75\textwidth}           ...     \end{minipage}       \end{figure*}  \begin{figure*}[h]     \begin{minipage}{0.75\textwidth}           ...     \end{minipage}       \end{figure*}  There is unintentional blank page inserted between the section title and the figures like the following.  How can I make latex not do this unintentional page break? Thanks. Update: I have tried using the float package with \begin{figure}[H]     \begin{minipage}{0.75\textwidth}           ...     \end{minipage}       \end{figure}  The problem with this is that I am using a two-column format and this made the picture overlay on each other.


If $\int_0^\pi f(t) \sin(t)dt =\int_0^\pi f(t) \cos(t)dt = 0$, then $f(x)=0$ admits two solutions

Let $f\colon [0,\pi]\to\mathbb{R}$ be a continuous function.  If $\int^{\pi}_{0}f (t) \sin(t)dt =\int^{\pi}_{0} f (t) \cos(t)dt = 0$, then $f(x)=0$ admits two solutions in $[0,\pi]$  I try to show if $f(x)>0$ and then get the contradiction but I failed to prove that, so maybe can someone help me with that? thanks in advance.


Add something to crontab programmatically (over ssh)

I have a deployment script, it must add something to a user crontab (trigger a script that clean logs every XXX days), however this must only be done during the first deployment, or when it needs to be updated.  (I can run xxx.py deploy env or xxx.py update env)  so I have to do this:  Check if my cronJob already exist Put my cronJob if it does not already exist or update my cronjob if one of the parameter of the command is different   I don't see how to add/check/remove something to the crontab without using crontab -e or editing the crontab file (download it, rewrite it, re-upload it)  PS : this is a user specific cronjob, "webadmin" is going to do it and he should not use sudo to do it.


How to prevent a droid from denouncing you?

I'm preparing a campaign of Star Wars Saga Edition, and I'm stuck with two of my player's backgrounds. The campaign takes place in 3 659 BBY, and the party is mainly composed of Sith.  The characters, a Jawa (Bob) and a droid HK-51 (John), serve the same master, a Sith Lord. The Jawa has became a Sith's acolyte, but is not supposed to possess a lightsaber. Nonetheless, he has disobeyed his master, and crafted one by himself in secret.  The problem is, "a HK-51 is fully and only loyal to his master, and would sacrifice his existence, rather than betray him in any way". My droid-player is really devoted to this aspect of his character.  The Jawa and me suggested two options:   The Jawa managed to put a "control bolt" (literally translated from French) on the droid, preventing John from telling Bob's secret to their master. The droid maintains that he would prefer to destroy himself. The Jawa could be in charge of the maintenance of the droid. Thus, John could calculate that it's best for everyone if he doesn't denounce Bob: their master could use two servants rather than one. John said that he would still denounce Bob, as he is fully loyal to their master.   Now, as a player, I understand the devotion of John toward his character. But, as a first time DM, it's kind of tricky to come out with a solution.  Is there a way to prevent John denouncing Bob?


How can I find files quicker than find or locate?

I have been using find command to find files on my 1 tb hard disk. it takes very long. then I used locate which proved to be faster with regular update using updatedb. But the limitation of locate is that I cannot find files with certain size or modified/created time. can you suggest me any ideas on how to find files at more speed or in that case how to pipe output of locate command in a way that all other information like size, time, etc. can be displayed or redirected to a file.


Metric on a Quotient of the Riemann Sphere

Let $P$ denote the quotient space obtained by the action of $\mathbb{Z}\backslash2\mathbb{Z}$ by the antipodal map $z\mapsto\frac{1}{z}$ on the riemann sphere $\hat{\mathbb{C}}$ (identified here with $\mathbb{C}\cup\left\{\infty\right\}$). I identify $P$ with the set:  $\left\{ z\in\mathbb{C}:\left|z\right|<1\right\} \cup\left\{ e^{it}:0\leq t\leq\pi\right\} $   that is to say, I use elements of the above set as the representatives for the equivalence classes in $P$. I am looking for formula for a function $f:P\times P\rightarrow[0,\infty)$ such that $f$ is a metric on $P$. Specifically, I would like a formula for $f$ that I can evaluate by plugging in representative elements in the above set (or something like that, more or less).  Thanks in advance.  Edit: forgive me for sounding desperate, but I cannot make due with an explanation of how to obtain such a formula. I want the formula.   An analogy for you if I have yet to make myself clear: suppose I was asking for the area of a square with side length $s$. The answers I have received so far for my question are akin to saying "multiply $s$ by itself" or "use the area formula for a square". The answer I am looking for is akin to saying "$s^{2}$". I need the formula. And please, no expressions with differentials, nor matrices, or any of that. I need to know how to compute the metric by using the complex numbers in the indicated set that I have identified with $P$.


Best practices for placing the Document Ready function

Sometimes I end up with a lot of code in the $("document").ready() function which usually sits inside the .html file.    $("document").ready(function() {     // The DOM is ready!     // Let the DOM manipulation begin!  });   What are the best practices for locating the $("document").ready(). Should it be in a different .js file and included in the HTML using:  <script src="MyDocReadyJS.js"></script>


Add file path to entity programmatically

I am creating an entity programatically, I want to set a file in entity, I have tried following method.  $file_path = '/sites/default/files/abc123.pdf'; $values = array(       'type' => 'review',       'uid' => $user->uid,       'status' => 1,       'comment' => 0,       'promote' => 0,     );   $tenant_review_entity = entity_create('node', $values);   $tenant_review = entity_metadata_wrapper('node', $tenant_review_entity);   $tenant_review->title->set($_POST['field_tenant_review_ref']['und']['form']['title']);    // adding file here   $tenant_review->field_tenancy_document->file->set($file_path);    $tenant_review->save();   If I am adding file path then getting following error  EntityMetadataWrapperException: Invalid data value given. Be sure it matches the required data type and format. in EntityDrupalWrapper->set() (line 737 of /var/www/html/rentspeak/sites/all/modules/entity/includes/entity.wrapper.inc).   If The file attaching code commented then entity is saving properly. Please suggest me where is the mistake. Thanks.


Is it theoretically possible to shield gravitational fields or waves?

Electromagnetic waves can be shielded by a perfect conductor. What about gravitational fields or waves?


Is there a C# method like Python's repr() to get the true representation of the object? Suppose we have:  string identifier = "22\n44"; Console.WriteLine(identifier);   This would return  22 44   Is there a way to get   "22\n44"   In Python this is easy. We can just do repr("22\n44").  I thought of this question because I was trying to convert "2244" to '2244' using   var identifier = "2244"; identifier = identifier.Replace("\"", "'"); Console.WriteLine(identifier);   The output is just 2244, because double quotes are for our purpose. But in my case, I  did this to get what I wanted:  identifier = string.Format("'{0}'", identifier);   because initially the database was receiving the query as IN ("2244") instead of IN ('2244') and was throwing Invalid Number error.


Why is it that when you wear polarized sunglasses, objects in the center of field-of-view are not obscured, but reflected lights have less intensity

I think that it has something to do with Brewster's Angle, but not really sure


macOS Sierra: Why do I have to enter the password for my private key?

I recently upgraded my computer to macOS Sierra. Everything went fine, but somewhere along the way something got changed (probably something I did) and now every time I try to ssh into another machine the terminal prompts me to enter my password. If I type the password and enter it the ssh session works as normal. But why do I have to enter my password at all? What can I do to fix this?   Side note: I have tried changing the file permissions to no avail. They are currently 644 like the public key.


Can you make cheese curds with pasteurized milk?

I have this recipe for cheese curds that I want to try: , but it specifically calls for raw milk which is near to impossible to get here. I make yogurt with pasteurized milk and it works no problem, but does cheese somehow work differently?


If $\alpha =2\pi/7$, find $\tan\alpha \tan 2\alpha + \tan 2\alpha \tan 4\alpha + \tan 4\alpha \tan \alpha$.   I tried by $7\alpha = 2\pi$ $4\alpha =2\pi-3\alpha$ $\sin 4\alpha = \sin 3\alpha$  But couldn't reach solution Please help


Align image at the bottom of text and have that text surround the image at the same time

I have researched for 30 mins to solve my problem without success... I want to have an image that always stays on the bottom right of some text but have part of the text to its left so that it always ends at the image's bottom.  I tried floating the image but it only stayed on the right, while the text was entirely on top of it. I don't want to put the image somewhere in the text, so that it comes up to this alignment. I want to somehow accomplish this by having this alignment of the code at all times :
Random text prevailed sincerity behaviour to so do principle mr. As  departure at no propriety zealously my. On dear rent if girl view.  First on smart there he sense. Earnestly enjoyment her you resources.  Brother chamber ten old against. Mr be cottage so related minuter is.  Delicate say and blessing ladyship exertion few margaret. Delight  herself welcome against smiling its for. Suspected discovery by he  affection household of principle perfectly he.
      Here's an example :


'80s sci-fi novel about about an astronaut returning to Earth to find it devoid of human life

I read this as hardcover from the library back in the 80's. The story involves an astronaut who returns to Earth from a long mission (50 years, 100?) and discovers everyone is missing.  The only computer system that he can access is a low-level system named HOMER. Homer proceeds to tell the story of what happened, that there was some sort of technology movement that overtook the world that led to all conscious beings transmigrating to a higher plane. Turns out the astronaut was to be their fail-safe to bring them back. Once the story is told, Homer is able to trigger their return. Things I remember:  Cover showed an overgrown city street  The techno revolutionaries had undergone genetic mods of some sort and were living in Antarctica.  There was an anti-revolutionary song that was a modified from a kids' song.  I remember a verse as being  The Ants come marching two by two, aroo, aroo The Ants come marching two by two, aroo, aroo Forth to the North to steal our warmth and they all go marching back to the pole again


Trying to export a path from inside a bash script

I am trying to put my whole environment set up into a single bash file. I am only hitting one issue. When I try to export a new path from inside the file it is not setting the path in the environment that the bash file was executed in. I want to do  >>sudo -H sh test.sh   Where test.sh is  bunch of installs  export PATH=/home/ubuntu/anaconda3/bin:$PATH  a second bunch of installs   I thought this was the purpose of eval so I tried  eval `export PATH=/home/ubuntu/anaconda3/bin:$PATH`   and  even   eval `echo "export PATH=/home/ubuntu/anaconda3/bin:$PATH"`   but I can't access the command in the terminal. If I do it manually it works.  ---------------UPDATE------------  The standard bash execution completes in a sub-shell so the environment variables are lost after execution. If you want to execute in the same shell then you  source test.sh   However, I need to be able to have full permissions in the execution so I need to use sudo. As explained  you cannot call sudo source but they did provide a hack to get it to work  source <(sudo cat /etc/environment)


Prove the following statement regarding geometry by induction

Prove by induction that $n$ straight lines that lie in a plane and are as such that none are parallel and there doesn't exist a point where some three lines cross, divide the plane on $$1+\frac{n(n+1)}{2}$$ parts.


I am given the following task: Calculate the first moment and variance of a log normal random variavle using the MGF. Well if it was as simple as using the normal procedure I'd be happy but my online searches tell me thhis MGF can only be approximated. How would you proceed ? Thanks


How do I combine/exclude multiple tags from a search?

I want to search for several related tags at once. When I type multiple tag-names in the search box, only one gets selected and I have to sift through a horde of non-pertinent questions.   E.g. 1: I want to find all questions where 'java' AND 'netbeans' AND 'tomcat' all are defined per question.  E.g. 2: (this may be a bit much to hope for) I want to find all questions where 'java' AND 'netbeans' BUT_NOT 'tomcat' is defined.  Alternatively, is there a way to search through the previous search results?  Is this possible?


I read a paper, and the paper use the following identities (that hold true in any ring)    $(I+AB)^{-1}A = A(I+BA)^{-1}$ $(I+AB)^{-1} = I - A(I+BA)^{-1}B$     Any way to prove this? How to open the term $(I+AB)^{-1}$ ?


Let $f$ be  a continuous and open map from $\mathbb R $ to $\mathbb R$.Prove that $f$ is monotonic.  Suppose that $f$ is not monotonic.Then $\exists a,b;a>b$ such that $f(a)<f(b)$ and $c,d;c<d$ such that $f(c)>f(d)$.Since $f$ is continuous then there exists no break in the graph of $f$. But how should I use the fact that $f$ is open.Any help on how should I do the proof?


How to register global (i.e., unique per file) properties?

I need to store additional information in a .blend file, that occurs only once per file. So, attaching it to, for example, bpy.types.Scene doesn't help.  Since bpy.data is an instance of bpy.types.BlendData, I tried attaching properties to bpy.types.BlendData. This failed:  >>> bpy.types.BlendData.testProp = bpy.props.StringProperty() >>> bpy.data.testProp (<built-in function StringProperty>, {})   Here, bpy.data.testProp is not a string, but some tuple, So it looks like registering properties on bpy.types.BlendData is not supported, like it is for bpy.types.Object:  >>> bpy.types.Object.testProp = bpy.props.StringProperty() >>> bpy.data.objects['Camera'].testProp ''   Is it somehow possible to attach properties to bpy.types.BlendData?  Are there other ways to register global data in a .blend file?


By default the file manager has several links in the left column:   Recent Home Desktop Documents Downloads Music Pictures Videos Trash   Can I make an option for 'Programming' in that list?  What steps would I need to do?    I specifically want to draw attention to the fact that I am using Ubuntu 16.10.  The link challenging this as a 'duplicate' question was for an older version of Ubuntu.  I am asking for instructions specific to Ubuntu 16.10


private void Label_GenerateMouseClicked(java.awt.event.MouseEvent evt) {                                                 // TODO add your handling code here:     try{         String sql = "select from Account ORDER BY RAND()";         PreparedStatement st = con.prepareStatement(sql);         ResultSet rs = st.executeQuery();          if(rs.next()){             TextField_Username.setText(rs.getString("EMAIL"));             TextField_Password.setText(rs.getString("PASSWORD"));         }     }catch(Exception e){         System.out.println("Cannot generate.");     } }                                              This code keep catching the error and i cant figure out why. im gettign error java.lang.NullPointerException. Please help


make unique key by combination of 4 filed?

I have 4 fields (project_id,domain_name,link_log,url) in unique key in my local database for store unique data,   data like -  project_id(int)--> 1224; domain_name (varchar)--> 'javatpoint.com'; link_log (int)--> 0 or 1; url (varchar)--> ''  according to sql the unique show like.. "1224-javatpoint.com-0-"  i want same unique key in salesforce.


Is it generally advisable to get anti-virus software for Mac OS X?

Is it worth to buy an anti-virus software for Mac OS X?  I heard both opinions like "it's not possible to get a virus on Mac OS X" and "Mac OS X is also vulnerable against virus... "  Which is true? What is the accepted practice, if any? Under what circumstances would anti-virus be advisable?


Is $\hat{\theta} = X_n$ an unbiased estimator of $\theta$?

Suppose $X_1 ,..., X_n$ is a random sample from u{0,$\theta$} consider the estimator $\hat{\theta} = X_n$, is it unbiased?  So far I have  E($\hat{\theta}$) = E($X_n$) = ${\theta}$($\frac{n}{n+1}$) therefore $X_n$ is a biased estimator but I have no clue if I'm even on the right track.


A finite abelian group that does not contain a subgroup isomorphic to $\mathbb Z_p\oplus\mathbb Z_p$, for any prime $p$, is cyclic.

Suppose that $G$ is a finite abelian group that does not contain a subgroup isomorphic to $\mathbb Z_p\oplus\mathbb Z_p$ for any prime $p$. Prove that $G$ is cyclic.   Attempt: If $G$ is a finite abelian group, then let $H$ be any subgroup of $G$  It's given that $H \not\simeq \mathbb{Z}_p \oplus \mathbb{Z}_p$ which can be due to a variety of reasons like : $|H|$ may not be $p^2$ or $H$ may not contain any element of order $p$ etc  Hence, the process of finding an element $g$ such that $|g| = |G|$ seems difficult, hence, probably the best bet would be to first assume that $G$ is not cyclic.  Hence,  $O(g) \neq |G|~ \forall ~ g \in G$ .   Also, $G \not\simeq Z_{|G|}$ since $G$ is not cyclic.  How do i arrive at a contradiction from here that if $G$ is not cyclic, it must contain a subgroup $H \simeq \mathbb Z_p \oplus \mathbb Z_p $.  Please note that this question occurs in Gallian before normal and factor groups are introduced.  Thank you for help.


Hey guys I can't for the life of me get the button to go to the bottom of the container using flexBox. I have tried multiple different things, and for some reason, it's being stubborn. I've actually used flexBox quite a bit so I am confused on why I am running into so much trouble. The button is currently in the middle of the DivCont with the background colorWhite. Here is my code and you can see on the bottom I even tried adding a div around the third button to test it out... Excuse the justify contentflex-end' spam import React from "react"; import { makeStyles } from "@material-ui/core/styles";  import { Link } from "react-router-dom";  const useStyles = makeStyles({   divCont: {     backgroundColor: "white",     display: "flex",     width: "250px",     height: "250px",     borderRadius: "10px",     margin: "40px",     flexDirection: "column",   },   button: {     display: "flex",     justifyContent: "flex-end",     alignContent: "flex-end",     alignItems: "flex-end",   },   mainCont: {     display: "flex",     flexDirection: "row",     justifyContent: "center",     alignItems: "flex-end",     alignContent: "flex-end",   },   h2: {     fontWeight: "normal",     display: "flex",     justifyContent: "center",   },    p: {},   buttonCont: {     display: "flex",     justifyContent: "flex-end",     alignItems: "flex-end",     alignContent: "flex-end",   }, });  export default function HomeMeunuGrid() {   const classes = useStyles();    return (

         {" "}
Custom Tubmlers

Hello to the world
         <button className={classes.button}>Click me</button>

Affordable Prices

 Hello to the world
         <button className={classes.button}>Click me</button>

Family Owned

 Hello to the world

           <button className={classes.button}>Click me</button>

   ); }


Why doesn't Data Explorer log in with Stack Overflow login?

I logged in with the same Gmail account that I use to log into all my other Stack Overflow accounts and it didn't auto-populate the name. Nor is it showing up here:    Seems like it ought to?


Can the validity start date of my UK visitor visa be changed to an earlier date?

I got my standard visitor visa for UK stamped and it starts from 15th April. But my flight will be reaching London on 14th April 7AM local time(due to my mistake of overlooking dates). I think airline will not allow me to board. I am currently in USA and am a permanent resident of USA with an Indian nationality.  Can I apply for change in dates to start a day early  or apply for a new visa? What are my options?   Thanks!


My party recently acquired some dragon bones. We split up the skeleton. I got the head and neck. One got the ribs and front legs. One got the wings and feet and one got the back legs and tail. I bought the rib cage for 125 gp. I don't know if that was a good idea but I did it. I want to know how I can use the neck bones, skull, and ribs.  Can anyone tell me what to do in this situation? Someone once suggested I use the ribs to reinforce my shield, but I don't know if that's allowed by the rules.   What are the guidelines around what can be done with dragon bones? I know I can just use them for cool decorations, but is there any rules support from getting any kind of benefit out of them?


Rotation around an edge (A newbie question)

Is it possible in Blender 2.8 to rotate an object (or a vertex group) around an edge? The edge then serving as an axis of rotation. If so, how is it done?


Database Log File Size Growth So Huge Unexpectedly

My database has two log files. Their sizes are growing very fast.  My backup sizes are becoming massive. I know that when I take full backup of my database, the log files are emptied but it is not. I can't control it.How can I control log growth?


I have an android app which calls upon a php script, the php script simply does this: echo "1" if true, echo "2" if false.   The android app buffers the script using:       InputStream inputStream = httpURLConnection.getInputStream();     BufferedReader bufferedReader = new BufferedReader(new           InputStreamReader(inputStream, "iso-8859-1"));     while ((line = bufferedReader.readLine()) != null) {                     result += (line);                 }   The problem I am having is that, my android app then compares the variable result with      if(result == "1")  But for some reason, the comparison always goes to the "else" and never hits the "if"  I have made sure my PHP script echos just "1", also made an alertdialog box to confirm that "1" is being returned to the variable "result"  Is it because of my inputstream? I am quite stumpped at the moment   EDIT: Also want to affirm that this is not a duplicate question to "how do you compare strings in java." My question is regarding comparing a PHP echo output, to Java's inputstream.


Find $a^3+b^3+c^3-3abc$ (binomial theorem)

$$a=\sum_{n=0}^\infty\frac{x^{3n}}{(3n)!}\\b=\sum_{n=1}^\infty\frac{x^{3n-2}}{(3n-2)!}\\c=\sum_{n=1}^\infty\frac{x^{3n-1}}{(3n-1)!}$$Find $a^3+b^3+c^3-3abc$: $(a)\ 1$ $(b)\ 0$ $(c)-1$ $(d)-2$  Please help me solve this question. I added $a,b$ and $c$. It gives me the expansion of $e^x$. But i dont know how to use it.


Find all solutions to $x^3+(x+1)^3+ \dots + (x+15)^3=y^3$

Find all pairs of integers $(x, y)$ such that    $$x^3+(x+1)^3+ \dots + (x+15)^3=y^3$$   What I have tried so far:  The coefficient of $x^3$ is $16$ in the left hand side. It is not useful then to trying bound LHS between, for example, $(ax+b)^3$ and $(ax+c)^3$ and then say that $ax+b<y<ax+c$.   I also tried to use modulo a prime. But it seems unlikely to bound variables this way.  EDIT : Though, it can be factored as $(2x+15)(x^2+15x+120)=(y/2)^3$. LSH factors are almost co-prime and we can say that $x^2+15x+120=3z^3$ or $x^2+15x+120=5z^3$. These are still too difficult to solve!  Any ideas?


Delete the contents of a huge directory in CentOS 6.6

I have a directory in my webserver that has 116 thousand cookie files in it.  How do I delete them?  rm -r /var/www/html/secured/cookies/*   I tried this but it does not work.  -bash: /bin/rm/: Argument list too long   That is the error given.


I need to design an edge detection circuit to detect when a square wave signal goes from Low to High (rising edge) and when it goes from High to Low (falling edge). The circuit should preferably use simple logic control such as 74LS series logic. I know people are gonna suggest using an arduino with interrupts but in my application this needs to be done in hardware rather than software.  Edit: The output is expected to be a short digital pulse, used as a trigger.


Do I use "I" or "me" in a compound subject?

I want to know the correct form:     He and I will go there   or   He and me will go there.   Which is correct?


Select data from "show tables" MySQL query

Is it possible to select from show tables in MySQL?  SELECT * FROM (SHOW TABLES) AS `my_tables`   Something along these lines, though the above does not work (on 5.0.51a, at least).