addClass work only on  elements that is in html file

Why this funcion add class only when you click on li elements that are originaly from html file. If i create new li element with add button, then add class doesnt work on it. How can i solve this?  <input type="text" id="new"><button id="add">Add</button>

one

two

three

   javascript  $(document).ready(function(){ $("li").click(function(){     $(this).addClass("current"); });  $("#add").click(function(){     var a=$("#new").val(); $("#list").append("
"+a+"
"); }); });


If have proven that $\frac{O(2)}{SO(2)}$ is isomporphic to $\mathbb Z_2$.  Does is follow from this that $O(2)$ is isomorphic to $SO(2)\times\mathbb Z_2$


Poll in background for StackExchange™ MultiCollider SuperDropdown™ inbox events and update the titlebar accordingly à la Facebook

I understand a few similar questions have been asked, but this is hopefully completely separate functionality.  Say you have Facebook open in Tab 1 of your favorite browser (mine is Chrome). When someone posts on your wall, comments, adds you as a friend (the list goes on), you get a number in the title of the page(tab) saying Facebook(1), indicating some sort of activity. The same thing happens if you're ON the page itself, I presume there is a notification ticker of some sort.  I already love the new  logo which does show notifications but only when you refresh look at the page.  I often find myself at work answering a question here and there and then I forget about it and do some actual work. 4 hours later, I click on my profile and BOOM, you have 8 comments, probably because you forgot to .Dispose() of an object or something :)  If my Stack Overflow tab title showed something like      (4) What's your favorite C# book?   Or, for pinned tabs, a browser will also indicate the title changed:    It would attract my attention to go and see who's complaining about my answer, if the OP needs more information or whether someone is just happy with my post.  So rather than refreshing Stack Overflow on an hourly basis, could we automate this and make our lives easier?   What do you think?


What is the point of checking in online?

Since it is often encouraged by airlines, I have adopted the habit of checking in online for flights, even if I am planning on taking suitcases with me.  How does this benefit me? If travelling with hand luggage only, one can often skip the check-in counters and proceed directly to security (an obvious timesaver), so let us assume that I will check bags.   I have seen very few airports with dedicated bag drop counters for the passengers who have already checked in at home, so I will have to queue just like those who didn't make use of online check-in. (However at the airports I've been at with such counters, the amount of time saved has been significant, sometimes with nobody waiting at the bag drop counter and dozens at the regular check-in counter.) Unless travelling on an ultra low cost carrier, airport check-in does not cost more.   How does it benefit the airline? There must be a reason they always send those reminder e-mails 24h before departure?   I don't think they are saving a lot of money on employees, since they still have to man the bag drop counters. Agents usually reprint my boarding pass without asking if I actually need one (I don't because I already have it), so printing costs are not reduced either. If everyone checked in at the airport and a passenger was delayed for boarding, it would be easier to decide if they should be waited for because they are already at the airport (i. e. checked in) or if the flight should just leave because they didn't even make it to the airport yet (i. e. not checked in).


UK: Is a 10 year ban still valid after acquiring new citizenship?

I am an Indian national and was refused a UK visa in 2009 in NYC and given a 10 year ban, but now I'm a US citizen.    Would the ban still apply if I wanted to visit the UK?


Proof that if $p\equiv3\,\left(\mbox{mod 4}\right)$ then $p$ can't be written as a sum of two squares

I'd appreciate your help showing that if $p\equiv3\,\left(\mbox{mod 4}\right)$   then p can't be written as a sum of two squares.  Thanks!


Why is it 'a Ukulele' and not 'an Ukulele'?

To the best of my understanding 'an' is used when a word starts with a vowel (an occasion), or sounds like it does (an honour). Ukulele sounds like it start with a u, so why isn't it prefixed with an 'an' ?


Nginx only recognises files in root dir (Permission denied on symlink'ed dir/files)

UPDATE -- This is driving me nuts (or back to Apache...)  The issue is definitely symlinks and permissions  When I setup symlinks to directories in the same tree, for example /var/www/html/html2 --> /var/www/html2 it works fine. Also /var/www/html/test_alias --> /var/www/html/test works fine. It's just when pointing out a different volume that I get 403. I have sprinkled all those directories with read and exec rights and nginx ownerships, but nothing works. I have also tried adding    sendfile off;   autoindex on;   disable_symlinks off;  but to no avail! There must be something fundamental I am missing??    OK so I'm a beginner with Nginx, however I have successfully setup a number of Apache websites, so this can't be that difficult right?  Well, not really. At least not for me. I have struggled for a couple of days while setting up a server that can interpret PHP code. Nothing fancy at all.  I have FINALLY a version of nginx.conf that somewhat works. It loads php and html in that order, and defaults to index.php and index.html.  My root is /var/www/html, owned by user nginx. Files in "html" loads OK, but when I symlinked a directory under "html", they won't load. Can anyone give me a hint about whats wrong?  This is my conf:  events {   worker_connections  1024; }  http {   index index.php index.html;   server {     listen 80 default_server;     server_name _; # This is just an invalid value which will never trigger on a real hostname.     server_name_in_redirect off;     root  /var/www/html;      location ~ \.php$ {       root           /var/www/html;       try_files $uri $uri/ =404;       fastcgi_pass   127.0.0.1:9000;       fastcgi_index  index.php;       fastcgi_split_path_info ^(.+\.php)(.*)$;       fastcgi_param  SCRIPT_FILENAME  $document_root$fastcgi_script_name;       include        fastcgi_params;     }   } }   Directory structure is:  /var/www/html   these files load OK  /var/www/html/mysite   these files are not found/loaded  It would be great if someone could give me a solution to this problem. And if you also know a good reference with simple config examples I'd love to hear about them. God knows there exist plenty with incorrect/outdated/plain confusing config examples.


I want to make the footer position at the bottom of the page. My code for footer is...   footer{   height: 80px;   background-color: rgb(93, 158, 255);   color: white;   text-align: center;   position: relative;   bottom: 0; }

Copyrigth &copy;

Designed by:  - Junior Web Development

         Result is


What creatures does Antimagic Field temporarily wink out of existence?

The  spell has the following effect on creatures:     A creature or object summoned or created by magic temporarily winks out of existence in the sphere. Such a creature instantly reappears once the space the creature occupied is no longer within the sphere.   Which creatures, or types of creature, fall within this category?    Obviously elementals or demons summoned by a spell will qualify. What about constructs such as golems?  What about undead animated by magic, like zombies? Stronger undead?


I have an equation $$ 6 \pmod {11} x = 3 \pmod{11} $$  and I need to find the variable x which solve the equation. I found that $ x=6 $ by trying $x=0,1,2,3,4,5$.  Before, posing this question, I made a search here and in youtube and found the way which described above: .  That`s an easy equation but the question is how can I find the variable without try all the options?


I am trying to understand the Vgs threshold on  datasheet. it says that the maximum is 1.45v but I have switched with 3.3 from a microcontroller. am i damaging the mosfet using this voltage?


What is wrong with my method of find the probability of a 2 pair?  For the first card we have 52 choices, one this is picked( call it A) we have 3 choices(different suite than A but this same value) for the second card, ( lets call this card B). Now we have AB, to we have to throw away 2 more cards so we don't have 3 of a kind or a four of a kind. Therefore one our third card we have 48 choices and on our fourth card we have 3 choices again similar to above.  On our last card we only have 44 choices left. So the probablity of getting a 2 pair should be (52*3*48*3*44)/(52 choose 5).  But this isn't correct.     Note: I edited this to "2 pair"; the original version was wrong.


Firefox developer desktop icon is missing

When I open Firefox from the launcher there is no icon.    When I run firefox from the terminal the icon appears. So far I have tried , but the issue still remains.   This is my firefox_dev.desktop file:   [Desktop Entry] Version=1.0 Name=Firefox Developer Edition GenericName=Web Browser Exec=/opt/firefox/firefox Terminal=false Icon=/opt/firefox/browser/icons/mozicon128.png Type=Application Categories=Network;WebBrowser;Favorites; MimeType=text/html;text/xml;application/xhtml_xml;x-scheme-handler/http;x-scheme-handler/https;x-scheme-handler/ftp; X-Ayatana-Desktop-Shortcuts=NewWindow;NewIncognito   I have tried uninstalling and then installing again, but the issue is still the same.


Two-sample Kolmogorov–Smirnov test with unequal samples

I did a simulation and the outcome's size was almost 30k. The other sample I want to compare them has only 50. Can I still do the test or should I radnomly pick 50 from the first and do it?


I am trying to make automatic message which will be sent on email but, when i start my program i get :  com.sun.mail.util.MailConnectException: Couldn't connect to host, port: localhost, 25; timeout -1;   I want it to be sent from localhost not exact email with password and username. code:  import java.io.BufferedReader; import java.io.File; import java.io.FileNotFoundException; import java.io.FileReader; import java.io.IOException; import java.util.*;  import javax.mail.*;  import javax.mail.internet.*;  import javax.activation.*;  import javax.mail.Session;  import javax.mail.Transport;    public class Email   {     public static void main(String[] args) throws IOException {         String recipient = "test@gmail.com";        String sender = "sender@gmail.com";        String host = "localhost";         Properties properties = System.getProperties();        properties.setProperty("mail.smtp.host", host);         Session session = Session.getDefaultInstance(properties);         try {            MimeMessage message = new MimeMessage(session);            message.setFrom(new InternetAddress(sender));            message.addRecipient(Message.RecipientType.TO, new InternetAddress(recipient));            message.setSubject("Test sub");             message.setText("Test MSG");             Transport.send(message);            System.out.println("Sent.");          } catch (AddressException e) {            e.printStackTrace();        } catch (MessagingException e) {            e.printStackTrace();        }     }     }   To run this class i am using javax.mail.jar. Does somebody know where the problem is ?


What's the explicit categorical relation between a linear transformation and its matrix representation?

There several questions about linear transformations and its respective matrices in some basis, but I'm particularly interested in the explicit definition of this relation in the category $Vect$ (of vector spaces and linear transformations.) Of course, a inevitable question is if there is always an matrix (or tensor, perhaps) representation (representable Functor?) for every morphism in an arbitrary category. Sorry if it is a silly question, but I'm learning CT by myself and it is difficult for me to understand this relation in categorical terms.


Different ways to prove there are infinitely many primes?

This is just a curiosity. I have come across multiple proofs of the fact that there are infinitely many primes, some of them were quite trivial, but some others were really, really fancy. I'll show you what proofs I have and I'd like to know more because I think it's cool to see that something can be proved in so many different ways.  Proof 1 : Euclid's. If there are finitely many primes then $p_1 p_2 ... p_n + 1$ is coprime to all of these guys. This is the basic idea in most proofs : generate a number coprime to all previous primes.  Proof 2 : Consider the sequence $a_n = 2^{2^n} + 1$. We have that  $$ 2^{2^n}-1 = (2^{2^1} - 1) \prod_{m=1}^{n-1} (2^{2^m}+1), $$  so that for $m < n$, $(2^{2^m} + 1, 2^{2^n} + 1) \, | \, (2^{2^n}-1, 2^{2^n} +1) = 1$. Since we have an infinite sequence of numbers coprime in pairs, at least one prime number must divide each one of them and they are all distinct primes, thus giving an infinity of them.  Proof 3 : (Note : I particularly like this one.) Define a topology on $\mathbb Z$ in the following way : a set $\mathscr N$ of integers is said to be open if for every $n \in \mathscr N$ there is an arithmetic progression $\mathscr A$ such that $n \in \mathscr A \subseteq \mathscr N$. This can easily be proven to define a topology on $\mathbb Z$. Note that under this topology arithmetic progressions are open and closed. Supposing there are finitely many primes, notice that this means that the set $$ \mathscr U \,\,\,\, \overset{def}{=} \,\,\, \bigcup_{p} \,\, p \mathbb Z $$ should be open and closed, but by the fundamental theorem of arithmetic, its complement in $\mathbb Z$ is the set $\{ -1, 1 \}$, which is not open, thus giving a contradiction.   Proof 4 : Let $a,b$ be coprime integers and $c > 0$. There exists $x$ such that $(a+bx, c) = 1$. To see this, choose $x$ such that $a+bx \not\equiv 0 \, \mathrm{mod}$ $p_i$ for all primes $p_i$ dividing $c$. If $a \equiv 0 \, \mathrm{mod}$ $p_i$, since $a$ and $b$ are coprime, $b$ has an inverse mod $p_i$, call it $\overline{b}$. Choosing $x \equiv \overline{b} \, \mathrm{mod}$ $p_i$, you are done. If $a \not\equiv 0 \, \mathrm{mod}$ $p_i$, then choosing $x \equiv 0 \, \mathrm{mod}$ $p_i$ works fine. Find $x$ using the Chinese Remainder Theorem.   Now assuming there are finitely many primes, let $c$ be the product of all of them. Our construction generates an integer coprime to $c$, giving a contradiction to the fundamental theorem of arithmetic.  Proof 5 : Dirichlet's theorem on arithmetic progressions (just so that you not bring it up as an example...)  Do you have any other nice proofs?


How do I set up a double elimination tournament with 18 participants. I can never get it to come out even.


How to implement on scroll action in lightning to show next few list of records

I want to render many(about 1000) components and I am displaying them through aura:iteration in another aura:iteration. This is causing me performance issues. I want to display only 10 records at an instance, and on scroll of mouse, load next 10 and so on...It should be like the way feed is loaded on a FB page or chatter. Any ideas how can this be implemented?     markup:   <aura:iteration var="outerListElement" items="{!v.listOfLists}">    <tr>       <aura:iteration var="singleEntry" items="{outerList">        <td >            <div class="slds-truncate">                <c:newComponent singleEntry="{!singleEntry}" outerListElement="{!outerListElement}" attr1="{!v.attr1OfParent}">            </div>         </td>       </aura:iteration>    </tr> </aura:iteration>


Why must $n$ be even if $2^n+1$ is prime?

This is a necessary step in a problem I am working on.


I have an ESTA, but it was from last time when we were in transit. This time we are staying in Hawaii. Do I need to update the ESTA?


How to fix the duplicate character lint error inside regular expression in android?

When I improve my code with Lint, there is inspection error with a duplicate character inside regular expression  private static final String IMAGE_LINK_PATTERN = "[(.*)![(.*)]((.*))(.*)](.*)"; private static final String IMAGE_LINK_REPLACE = "$1$4";      Duplicate character '(' inside character class   Duplicate character '.' inside character class   Duplicate character '*' inside character class   Duplicate character ')' inside character class   Duplicate character '(' inside character class   Duplicate character ')' inside character class   these is no problem with the regular pattern, so how to suppress this lint error?


Show that $(0,1]$ ~ $(0,1)$ by constructing a one-to-one correspondence between the two sets. I have seen the other example on here, but I am not sure how exactly to prove it. Do I need to come up with a function that is one-to-one and onto and show that I can map a point from one set to the other set?


If I know a flight is delayed can I turn up late for check-in at the airport?

This is the scenario:  I have tickets booked for a 13:40 scheduled flight with Emirates. I need to check bags in so plan to be at the airport at the advised 2 hours before flight departure (11:40) but I look ahead and see my plane is delayed and not scheduled for departure until 16:40.   Can I arrive at the airport at 14:40 to check-in or should I knowingly arrive at the airport a full 5 hours before the revised departure time?  Footnote: The reason of the delay is that the inbound flight which will become be my outbound flight after turnaround is delayed in arriving at my departure airport.


Evaluate $\lim_{x\to 0} \sin (\frac {1}{x})$

Evaluate:     $$\lim_{x\to 0} \sin (\dfrac {1}{x})$$   My Attempt:  let $$\dfrac {1}{x}=k$$ As $\dfrac {1}{x}\to 0$, $k\to \infty$ Now, $$=\lim_{k\to \infty} \sin k$$


Height/Radius ratio for maximum volume cylinder of given surface area

I am a bit confused by this problem I have encountered:  A right circular cylindrical container with a closed top is to be constructed with a fixed surface area. Find the ratio of the height to the radius which will maximize the volume.  I know the volume to be $ \pi{r}^2h$, but I don't see what equation I should be solving for. How can I solve for the ratio?  Thanks


How to display a virtual table generated by MySQL query in HTML page

I have this MySQL table MONTHNAME generated by querying from the database using the following script using PHP.   $query = 'SELECT monthname(`dateAdded`) as MONTHNAME,sum(`shift1PinCount`+`shift2PinCount`) from `supervisorupdate` WHERE YEAR(`dateAdded`) = YEAR(CURDATE()) group by monthname(`dateAdded`) ORDER BY monthname(`dateAdded`) DESC'; $queryExecute = mysqli_query($conn, $query);     I want to show this table as it is into my HTML page using PHP. As from I know normally we use  while($row = mysqli_fetch_array($queryExecute)){    echo $row['someColumnName']; }   In this case, I can't do that since I am doing some calculations and getting output as a table. Can someone guide me on how to show this table?  Edit 1  Here is a picture of the result that I am getting using phpMyadmin. So the HTML table should be similar to this    So for HTML side, it should show something like this

       Month	       Sum

       January	       3456

       February	       443


Word for "studying a research article to get the most out of it"?

From the Word web dictionary:     Study: Consider in detail and subject to an analysis in order to   discover essential features or meaning   Particularly, I am looking for a word (synonym of 'study') which describes reading the research literature thoroughly (e.g. in order to review it), and getting the most out of it.   Actually I am writing a proposal for a software application to search and read research literature. So I want to say that it will be designed and optimized in a way that you can get the most out of reading the research articles (because of features like highlighting terms of interest, e.g. highlighting all names of cars in an article about different automobile manufacturers).  So I want a word used in this kind of meaning/context. Any suggestions are welcome.    Edit: I just applied bold format to the part of the question which describes why it is different from the other question, i.e. a part of my question is that the word/phrase should describe that there are features available to get the most out of the reading experience.


When is a map $ f : A^{n+1} \to A^n $ injective?

Is there an example of a commutative ring $ A $ with unit $ 1_A $ and an $A$-module map : $ f : A^{n+1} \to A^n $ such that $f$ is injective ?  If the answer is yes, when is this enunciation false ?  Thanks in advance for your help.


GRUB DEFAULT =0 GRUB TIMEOUT =5 GRUB DISTRIBUTOR= 'LSB RELEASE -i - s 2> /dev/null | | echo Debian' GRUB_CMDLINE LINUX_DEFAULT ="quiet" GRUB_CMDLINE_LINUX=" "   which OS will boot by default What setting would you use if i wanted to boot the 3rd OS by default can someone also explain what the significance of the line GRUB_TIMEOUT=5 and what would happen if i completely omitted this line from the configuration file.


Issue while accessing template from other class

So I have quite a straightforward implementation written in C++ that uses templates to to some operations to a std::vector. The problem is that whenever I try to call the method that does something on a vector, compilation gives me this error:  basavyr@Roberts-MacBook-Pro src % g++ -std=c++17 -I../include/ energyExpressions.cc pr135.cc data.cc main.cc - O3 Undefined symbols for architecture x86_64:   "void EnergyFormula::kevTOmev<double>(std::__1::vector<double, std::__1::allocator<double> >&)", referenced  from:       _main in main-9a2141.o ld: symbol(s) not found for architecture x86_64 clang: error: linker command failed with exit code 1   Is this really related to my CPU architecture? And why/how can one avoid such situation? Is there another efficient/smart way of solving this?  Here is the code I have written:  in the include file:  #ifndef ENERGYEXPRESSIONS_HH #define ENERGYEXPRESSIONS_HH  #include <vector>  class EnergyFormula { public:     //N=0 wobbling band     double yrastBand(double params);      //N=1 wobbling band     double wobblingBand(double params);      template <typename T>     void kevTOmev(std::vector<T> &); };  #endif // ENERGYEXPRESSIONS_HH   in the expression.cc file:  #include "../include/energyExpressions.hh"  template <typename T> void EnergyFormula::kevTOmev(std::vector<T> &vec) //using reference because I don't want to copy the vector, I just want to modify it directly {     auto mev = 1000;     for (int i = 0; i < vec.size(); ++i)     {         vec.at(i) = static_cast<T>(vec.at(i) / mev);     } }    now in my main.cpp:  #include <iostream> #include <vector> #include <string> #include <ctime>  #include "../include/pr135.hh" //some other stuff #include "../include/data.hh" //some other stuff #include "../include/energyExpressions.hh"  int main() {  EnergyFormula *formulas = new EnergyFormula;  formulas->kevTOmev<double>(test3);     for (auto &&n : test3)     {         std::cout << n << " ";     }      delete nucleu;     v1.clear(); }   macOS Catalina latest update with latest CLANG by the way.


Ways to navigate grid with path restriction

I want to go from $(0,0)$ to $(8,8)$ in this $8\times8$ grid. I can only move up or right.    However, I have to avoid the points $(3,3), (3,4), (4,3), (4,4)$ ($a,b,c,d$ in the figure). How many distinct paths are possible?


Navigating to the edit mode of a not-exist page produces a strange error message

Visiting  produces "404 error" but visting  produces "There is a pending suggested edit in the queue, try again in a few minutes." Is it a bug?  When attempting to visit the page (not in edit mode):    When attempting to visit the page (in edit mode):


LNK2019: How to include headers in C++ such that a template definition compiles?

I have the next situation: //B.h class B {   template<typename T>   void b(T input); };  //B.cpp #include "B.h" template void B::b<int>(int); template void B::b<float>(float); template<typename T> void B::b(T input) {...}  //C.h // Because of constraints no B here, but B included in cpp file class C {   template<typename T>   void c(T& obj);   int cInt; };  //C.cpp #include "C.h" #include "B.h" template void C::c<B>(B&); template<typename T> void C::c(T& obj) {obj.b(2);}  //main.h #include "B.h" #include "C.h" // ... B bo; C co; co.c(bo); // ...  I get LNK2019: Unresolved external symbol B::b(int) referenced in function C::c(B&). Any ideas on how I could solve this?


Making a long table continue over two columns

I am using multicol to make a two-column document using the book document class. I have a long tabular that I want to break where the page breaks and then continue in the next column.  I could split it into two tables, but I want their width and such to be the same. I've tried with longtable but can't get it to work.  I basically want the table to split and arrange itself into two columns just like normal text does.  Edit: Sorry for the lack of information. With just 1 column it works fine with longtable, but when I use multicols it breaks down and just continues outside the page. I also get an error while compiling.     Package longtable Error: longtable not in 1-column mode.   This is a simplification of my code:  \documentclass[11pt,a4paper]{article}  \usepackage{multicol} \usepackage{longtable}  \begin{document}  \begin{multicols}{2}  \begin{longtable}{ccc} Header of first column & Header of second column \\ \endhead Table cell 1, 1 & Table cell 1, 2 \\ Table cell 2, 1 & Table cell 2, 2 \\ Table cell 1, 1 & Table cell 1, 2 \\ ... ... \end{longtable}  \end{multicols}  \end{document}     I hope this is enough information. Any thoughts?


Theorem 17.5 Gallian: A polynomial generates a maximal ideal if and only if it is irreducible.

Let $F$ be a field and $p\in F[x]$ a polynomial. Then $\langle p(x)\rangle$ is maximal if and only if $p(x)$ is irreducible.  The proof goes as follow: Suppose first that $\langle p(x)\rangle$ is a maximal ideal $\operatorname{in} F[x] .$ Clearly, $p(x)$ is neither the zero polynomial nor a unit in $F[x],$ because neither $\{0\}$ nor $F[x]$ is a maximal ideal in $F[x] .$ If $p(x)=g(x) h(x)$ is a factorization of $p(x)$ over $F,$ then $\langle p(x)\rangle \subset\langle g(x)\rangle \subset F[x] .$ Thus, $\langle p(x)\rangle=\langle g(x)\rangle$ or $F[x]=\langle g(x)\rangle$. I don't understand from the factorization of $p(x)$, we can deduce the relationship between $\langle p(x)\rangle,\langle g(x)\rangle$ and $F[x]$


Proving the bounds of the cosine sequence without starting with basic trig identities.

If we look at a unit circle we can see that the values of cosine are between -1 and 1. However is there a particular proof for this fact? I have tried using the Euler's identity to arrive at a proof with no luck. I have also tried using the expanded form of cosine : $\cos(x)=\sum_{n=0}^{\infty } \frac{(-1)^n x^{2n}}{2n!}$. Using the expansion I tried to manipulate as much as I could however it seems that I am not finding a proof in this fashion either. I also tried going from the fact that it is a Cauchy sequence. I know that identities can be brought in to prove it, but I should like to find a more fundamental way of proving it. Any ideas?


I am new to lubuntu. I have installed java8 in my laptop. i need to set up environment variable (sudo nano /etc/environmet) i have entered the JAVA_HOME =" path" but i dont know how to properly save and exit the window. Can you please help me with this ?


Let $A_1$, $A_2$ be groups and $\phi:A_1\to A_2$ surjective with $G_1\unlhd A_1$ and $\phi(G_1)=G_2$. Is $A_1/G_1\cong A_2/G_2$?

Let $A_1$ and $A_2$ be a group and $\phi: A_1 \to A_2$ be a surjective group homomorphism. Also, $G_1 \unlhd A_1$ and $\phi(G_1) = G_2$. I have to prove/disprove this statement: Is $A_1/G_1 \cong A_2/G_2$?   My claim is that the statement is true. I first showed that if $G_1 \unlhd A_1$, then $G_2 \unlhd A_2$. Then, I defined two maps: $f:A_1/G_1 \to A_2$, which is an isomorphism by first-isomorphism theorem. And then, another map $j:A_2 \to A_2/G_2$, which is a surjective group homomorphism. I thought that this would work, but without being able to prove that $j$ is injective, I cannot show that $j$ is a bijection. Can anyone check my work? Or is the statement false?


Why didn't Harry Potter tell Aunt Petunia he was rich to improve how he was treated by Dursleys?

This is a follow-up question to   One reason Aunt Petunia mistreated Harry was that she did not know he was rich. If she knew, she would naturally have treated this golden goose nicely. Her retirement would be secured if Harry financially supported her in old age.  Why didn't Harry tell Aunt Petunia he was rich? Surely every boy wants to be treated nicely by his family.


Fastest way to check if WCF endpoint is listening

Often, if a WCF endpoint is unavailable (in my case, usually because the service host is not running), I'll get an EndpointNotFoundException after a timeout.  I'd like to have a fast way to query the service to see if it's available without having to rely on the normal timeout.  In other words, I want to keep a normal timeout for normal circumstances, but for a quick "ping" of the endpoint, I want it to fail fast if it's not available right away.  How could this be accomplished?


Quadratic equation - arithmetic progression

The coefficients of a quadratic equation $ax^2+bx+c=0$ are in arithmetic progression and $a, b, c$ all are positive. If the roots of the equation be $k$ and $l$ are integers.Then $k +l+kl$ =?


The cow in the field problem (intersecting circular areas)

What length of rope should be used to tie a cow to an exterior fence post of a circular field so that the cow can only graze half of the grass within that field?  updated: To be clear: the cow should be tied to a post on the exterior of the field, not a post at the center of the field.


Inverse Trigonometric Functions and Summation of Series

I am aware that these types of questions are dealt with by the properties of $\tan^{-1} x_r-\tan^{-1} x_{r-1}$ but here I am not able to proceed by that approach...PLEASE HELP!  $$ \sum_{r=1}^\infty\tan^{-1}\left(\frac{2r}{1-r^2+r^4}\right) $$


1,5,9,13,17...Is a sequence with inf many primes. How to show using Gaussian integers?

I decided to take the product of each term in the sequence and add I to the result. My main issue is that I do not know how to show that this resulting number must have a Gaussian prime factor q which has a Split primagon. If I can show this, then my idea was to show that q*q' is a prime integer within the sequence where q' is the conjugate of q.  Showing the product has a Gaussian prime factor isn't difficult, but I'm not sure how to how it's split, nor am I sure why only the split case allows for q*q' to produce a prime within the sequence.


Using my idle computer for something useful (seti@home and the like)

Just wondering how I can put my idle computer time to some real use  what services like seti@home are out there and worth supporting ?


Intermediate Rings that are not finitely generated

Let $R_1$ and $R_2$ are two rings such that $R_1$ $\subseteq$ $R_2$ and $R_2$ is a finitely generated ring over $R_1$. We know that, if $R_1$ is Noetherian and $S$ is a ring such that $R_1$ $\subseteq$ $S$ $\subseteq$ $R_2$ and $R_2$ is a finitely generated module over $S$, then $S$ is a finitely generated ring over $R_1$.   I found out in the June edition of The American Mathematical monthly that if we remove the condition that "$R_2$ is a finitely generated module over $S$", then there exists examples where $S$ might not be a finitely generated ring over $R_1$ and they construct an example using heavy machineries, I was thinking whether a 'simpler' example could be constructed.  And Also if one could provide a general algorithm on constructing such rings, it will be very much appreciable.


How to install the Boot-Repair tool in an Ubuntu live disc?

When the bootloader (GRUB) is broken, I cannot access neither Ubuntu nor Windows.  I heard that an easy solution to fix this is to use the Boot-Repair tool from an Ubuntu liveCD (or liveUSB).  What are the steps to do this?


I already have Ubuntu and I want to dual boot windows alongside this beautiful operating system. Can I get a tutorial from someone where I don't have to re-install Ubuntu and start from scatch? Thank you, Ubuntu users.


Show that if a and b are relatively prime, then their sum and product are also relatively prime.

I tried to use the fundamental theorem of arithmetic where I represented each a and b as products of primes. However, i seem to have gotten stuck in the middle. Can anyone help me? Thanks!


I've recently received an image of CentOS 7 and I'm having issues with resolving hosts. I'm currently on a company's VPN and all company's resources are available to me.   The problem is: nothing else is available. I've been trying to access websites like google.com and github.com and I'm getting errors like  unknown host google.com   How do I configure my resolver to fix this?  Contents of my /etc/resolv.conf:   # Generated by NetworkManager search vbox nameserver 10.3.1.1 nameserver 10.3.1.2 nameserver 172.23.28.7 # NOTE: the libc resolver may not support more than 3 nameservers. # The nameservers listed below may not be recognized. nameserver 172.23.28.8   Result of host google.com 8.8.8.8   Using domain server: Name: 8.8.8.8 Address: 8.8.8.8#53 Aliases:  google.com has address 216.58.208.142 google.com has IPv6 address 2a00:1450:4009:803::200e google.com mail is handled by 10 aspmx.l.google.com. google.com mail is handled by 20 alt1.aspmx.l.google.com. google.com mail is handled by 50 alt4.aspmx.l.google.com. google.com mail is handled by 40 alt3.aspmx.l.google.com. google.com mail is handled by 30 alt2.aspmx.l.google.com.   Result of dig @8.8.8.8 google.com  ; <<>> DiG 9.9.4-RedHat-9.9.4-29.el7_2.3 <<>> @8.8.8.8 google.com ; (1 server found) ;; global options: +cmd ;; Got answer: ;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 57064 ;; flags: qr rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 0, ADDITIONAL: 1  ;; OPT PSEUDOSECTION: ; EDNS: version: 0, flags:; udp: 512 ;; QUESTION SECTION: ;google.com.                    IN      A  ;; ANSWER SECTION: google.com.             299     IN      A       216.58.208.174  ;; Query time: 25 msec ;; SERVER: 8.8.8.8#53(8.8.8.8) ;; WHEN: Fri Dec 02 11:13:43 GMT 2016 ;; MSG SIZE  rcvd: 55


Why is my PC freezing while I'm copying a file to a pendrive?

I have a really strange situation here. My PC works fine, at least in most cases, but there's one thing that I can't deal with. When I try to copy a file from my pendrive, everything is ok -- I got 16-19M/s , it works pretty well. But when I try to copy something to the same pendrive, my PC freezes. The mouse pointer stops moving for a sec or two, then it moves a little bit and it stops again. When something is playing, for example, in Amarok, the sound acts like a machine gun. The speed jumps from 500K/s to 15M/s, average 8M/s. This occurs only when I'm copying something to a pendrive. When the process of copying is done, everything backs to normal.   I tried everything -- other pendrive, a different USB port on front panel or those ports from back, I even changed the USB pins on motherboard (front panel), but no matter where I put my USB stick, it's always the same. I tried different filesystem -- fat32, ext4. I have no problem with the device on Windows, on my laptop. It has to be my PC or something in my system. I have no idea what to look for. I'm using Debian testing with standalone Openbox. My PC is kind of old -- Pentium D 3GHz, 1GiB of RAM, 1,5TB WD Green disk. If you have something that would help me to solve this issue, I'd be glad to hear that.  I don't know what else info I should provide, but if you need something, just ask, I'll update this post as soon as possible.  I tried to reproduce this problem on ubuntu 13.04 live cd. I mounted my encrypted partition + encrypted swap and connected my pendrive to a usb port. Next I tried to start some apps, and now I have ~820MiB in RAM and about 400MiB in SWAP. There's no problem with copying, no freezing at all, everything is as it should be. So, it looks like it's a fault of the system, but where exactly? What would cause such a weird behavior?


What features should I look for in a filter system to avoid buying duplicates later

I’m looking to buy some kind of filter system. What features in a filter system should I as a begginer look for so that I will not have to replace everything (or buy duplicates in other sizesk) down the line?  I’m initially interested in ND an polarizing filters and am using the Canon EOS system. Planning to get the 5D mark II and 17-40 when I find a good deal for them? Using a 350D now.


Using keyboard disables touchpad left button for a second on Acer laptop in Windows 8.1

The problem is present in the whole system not only in games: desktop, chrome, games, everywhere. When I press any "input key" on a keyboard for example in desktop I can't select the file by left mouse button OR by tapping the touchpad for about one second(right button works immediately). Later on the LMB works well. There is NO delay, button is just deactivated for a second. In games that means that when I run I cannot shoot for example. When I switched LMB and RMB functions in windows control panel still the LMB is getting disabled and RMB works fine. By "input key" I mean letter or a number, keys like Alt, CapsLock, Ctrl does not affect touchpad. I do not remember that problem when I used Windows 7. USB mouse works like it should.  The problem existed when I was using Elantech touchpad driver and after I uninstalled it and used Windows 8.1 generic driver.  EDIT I installed the Elantech drivers and set values to 0 at every disable... key. But the problem is still present.  EDIT 2  THE LAPTOP IS Acer V3-571G  I have turned off disabling function in touchpad but it did not fix it. I know that touchpad is NOT broken down.   Turned on the animated touchpad icon of elantech drivers and put it on the task bar(on a picture) When I type the letter and press the LMB the dynamic icon displays the click but it is ignored.


Could you explain why $\frac{d}{dx} e^x = e^x$ "intuitively"?

As the title implies, It is seems that $e^x$ is the only function whoes derivative is the same as itself.  thanks.


Upgrading My MacBook Pro (Late 2013) Components

I have a MacBook Pro (Retina, 13-inch, Late 2013) with the following specs:   2.4 GHz Intel Core i5 Processor;  8 GB 1600 MHz DDR3 Memory; and  Intel Iris 1536 MB Graphics.   I wanted to upgrade the Processor and Memory but having read some passages online, it seems as though I will be unable to do so.   Can anyone confirm this? Am I unable to upgrade my device?   If I can upgrade anything, what can I upgrade and how can I go about doing this?  Thank you in advance.


Can I edit the hosts file on my android without root access?

I'd like to block access to websites on my Pixel 3 android device. The parental settings leave much to be desired and apps like BlockSite don't work across all browsers. (In this case - it doesn't work in firefox)   Here's what I tried so far   adb pull /system/etc/hosts ~/Documents/android/hosts   I edited the hosts file and got it ready to be transferred back.  adb push ~/Documents/android/hosts /system/hosts   This gave me error message: adb: error: failed to copy '/Users/[username]/Documents/android/hosts' to '/system/hosts': remote couldn't create file: Read-only file system  Per this  and this , I tried a few other options.  I tried to use these commands   adb root adb disable-verity adb reboot adb root adb remount   This gave me error message: adbd cannot run as root in production builds and when I tried adb disable-verity it said: verity cannot be disabled/enabled - USER build.  I tried to use this command  adp remount   This gave me error: Not running as root. Try "adb root" first.  I downloaded an emulator and tried this command on my device  mount -o rw,remount /system mount -o ro,remount /system   Similarly, this was unsuccessful


What does each graph cuadrant means with LDA vis plot from R?

I am speeking about  graph, that shows a big probability mass.  This is the way that it finally shows with some data I found online and used to understand Latent Dirichlet Allocation topic modeling. As far as I understand, this graphic is ideal to give out final names to each topic according to the frequency or relevance of each term given the topic but I've got two questions: 1. What would you simply say about topic 8 position on the graph? Meaning that I can't tell what each square represent in this graph, I can't tell in plain words what's the difference between topic 1 and 10, or topic 8 and 3, given their position on this graph. 2. What can you tell about the big gray line in comparisson to the red filling when lambda is 0? I mean, I think I get that when lambda is 1, it's meaning about plain frequency of the term in the whole corpus vs the frequency of the terms in that topic, but I'm not sure I get it with putting more wight in the ratio from red to gray, what is the gray line saying about that term and how is red contransting?


Most efficient (cost & time) way to get a good Gavel of Judgement

I'm looking for a strong gavel to play the HotA build with my season barb but I'm only finding mediocre ones. If I wanted to dedicate time specifically towards creating/finding a strong gavel, what would be the most efficient route?  Simply rifting and waiting for one to drop seems inefficient. What about cube-rerolling an existing gavel vs. upgrading 2h mighty weapons, how do they compare? Could someone create a numerical breakdown of the possible options?  This question could use a "Theorycrafting" tag, but I couldn't create it.    TL;DR: Looking for the most cost and time efficient way to roll loads of gavels in a manageable timeframe, would like numerical breakdown of options.


Algebraic closure of $\mathbb{C}(x)$ is isomorphic to $\mathbb{C}$

Let $x$ be transcendental over $\mathbb{C}$. Let $K$ be the algebraic closure of $\mathbb{C}(x)$. How to show that $K$ is isomorphic to $\mathbb{C}$?


Does Java really always copy all objects passed to a method?

Java is pass-by-value. This means that a called method acts on a copy of an object that was passed in, not on the original object.  If the object is not changed in the method, creating an actual copy seems unnecessary. So a compiler that implements the program to create such a copy would be pretty inefficient. Are all Java compilers (javac, gcj, ECJ, etc.) really doing that?  At least in the case where a parameter is declared final it would make a lot of sense not to copy.  EDIT  OK, so objects are not copied. I got confused because String is special in that it is copied (immutable). Sorry about my unknowings. Just to make up for it, here is a thousandth example of what happens when an object is passed:  import java.lang.System;  class C { int member; }  public class Test {     static void subMethod(C object) { object.member=1; }      public static void main(String[] args) {         C object = new C();         object.member=0;         subMethod(object);         System.out.println(object.member);  // prints "1"     } }


With the following line i get a DATE in Y-m-d format.  echo date('Y-m-d',strtotime($result["created_at"]));   Its the creation date of an account. now id like to calculate how old the account is so i can print it out like  5 Years, 5 Months as a example.  any ideas?


I heard using 'could' is for politeness. When I request something, should I say "Can you please" or "Could you please"? Does the latter sound over-polite and pretentious?


I'm a Siren and I'm getting almost nothing but Fire elemental guns; about 90% of guns have been fire, most of the rest Explosive and a scare few Shock.  Are the elemental varieties more common at different levels? I've seen zero corrosive/shock guns so far. I'm level 12 at the moment.


Let $R$ be a ring. What does it mean to be an $R$-algebra?  I missed the definition in my lectures and when I search online, I can only find definitions of what a ring is.


So I have this induction problem:     $$n^2 ≤ 2^n \;\text{ for } \; n ≥ 4$$   I know the base case is ($n=4$) which checks out.  I know the hyp is ($n=k$) giving $k^2 ≤ 2^k$.  However, I am getting stuck on the actual proof part (i.e. $n = k+1$).  I know $2^{k+1}$ can be broken apart into $2\times 2^k$ but I haven't seen where that can help.  Edits:  Expanding out the $(k+1)^2$, I get $k^2 + 2k + 1 ≤ 2^{k+1}$ Using the hyp I can do $2^k + 2k +1 ≤ (2)(2k)$


You have a $5$ card hand from randomly shuffled standard deck of $52$ cards:   $X$ - Event that hand exactly contains $1$ spade $Y$ - Event that hand exactly contains $1$ ace   How do I calculate $P(X \cup Y)$?


I am trying to generate a map with terrain and elevation in QGIS and as a beginner I have followed tutorials on how to generate contours and hill shades succesfully. However, I don't know what are the next steps in order for me to  apply style/colors on based on the elevation. As for my project I am using Global Elevation GeoTIFF from . I am not sure though if this is the right base map/file that I should use to produce what I want, or if this produces accurate elevation data. The map I need to achieve is a terrain + elevation map just like what  uses. Also, if I am able to do this, will there be a way to stitch or collage multiple layers from different sections of a map since processing the entire map takes forever, whilst for a certain country only takes a minute.


Is it possible to remove the label on lightning:namespace components?

I would like to use the lightning:input component in a data table. Therefore my question is: Is it possible to remove the label attribute on the lightning component?  <lightning:input type="number" label=" " name="aNumberInputField" />   is quite not the solution for this (shifted... doesn't look good), and removing the attribute throws an error. Any advise?


Validation Rule Assist: Lock down multiple lead fields after they are first populated

I am trying to create a validation rule to lock down our original utm fields on leads after they are first populated.  Essentially I would like to prevent everyone (including our marketo sync user) but a 'system admin' to be able to update the fields below.  I think I have the Rule down for the most part, but I keep getting a syntax error "Missing ')'", please see below. Any help would be appreciated.  AND(     $Profile.Name <> "System Administrator",     ISCHANGED( OG_Lead_Source__c ),     NOT(ISBLANK(PRIORVALUE( OG_Lead_Source__c )))     ISCHANGED( OG_Lead_Medium__c ),     NOT(ISBLANK(PRIORVALUE( OG_Lead_Medium__c )))     ISCHANGED( OG_Lead_Campaign__c ),     NOT(ISBLANK(PRIORVALUE( OG_Lead_Campaign__c )))     ISCHANGED( OG_Lead_Content__c ),     NOT(ISBLANK(PRIORVALUE( OG_Lead_Content__c )))     ISCHANGED( OG_Lead_Term__c ),     NOT(ISBLANK(PRIORVALUE( OG_Lead_Term__c ))) )


Why these are isomorphic each other for given these rings?

For the ring $\mathbb{Z}_{15}[x]$ and its ideal $<3x^2 + 5x>$  Find the order of the $\mathbb{Z}_{15}[x]/<3x^2 + 5x>$    In my answer sheet it said   $\mathbb{Z}_{15}[x]/<3x^2 + 5x> \simeq (\mathbb{Z}_{3}[x]/<5x>) \times (\mathbb{Z}_{5}[x]/<3x^2>)$  Hence the order is 75.   I don't understand Why does $\mathbb{Z}_{15}[x]/<3x^2 + 5x> \simeq (\mathbb{Z}_{3}[x]/<5x>) \times (\mathbb{Z}_{5}[x]/<3x^2>)$.   Why those are isomorphic each other?


cardinal of conjugacy class of $(123)(456)$ in $A_7$

So it is not hard to see that the conjugacy class of $(123)(456)$ in $S_7$ has cardinality $\frac{7!}{3\cdot 3\cdot2}=280$.  But for instance to go from $(123)(456)$ to $(132)(456)$ you have to conjugate by $(23)$ which is not in $A_7$ so $(132)(456)$ is not in our class (call it $C$). Same for $(123)(465)$. But $(132)(465)\in C$ because $(23)(56)\in A_7$.  I could probably find all the elements of $C$ by trying out different permutations but I feel like there is a better way...  We know that $|A_7|={|S_7|\over2}$ and conjugating $(123)(456)$ by any permutation in $S_7\supset A_7$ gives a permutation of the type $(abc)(def)~$ with $a,...,f\in\{1,...,7\}$ and $a,b,...,f$ are disjoint because otherwise the "permutation" by which we conjugate wouldn't be bijective.  So I'm tempted to say that $|C|=|\bigcup\limits_{~a\in A_7}\{(~a(1)a(2)a(3)~)~(~a(4)a(5)a(6)~)~\}|=\frac{280}{2}$ but that's probably false.  A hint would be appreciated


Plural or singular after uncountable noun connected with "and"?

What is the correct use?  His stool and urine ARE normal. His stool and urine IS normal.


How to write a generic print for vector of vectors using c++

My Initial implementation approach in .cpp is like the following:  using namespace std; ... template <typename T> void print2dvector(vector<vector<T> > v) {     for(int i = 0; i < v.size(); i++) {         for(int j = 0; j < v[i].size(); j++) {             cout << v[i][j] << " ";         }         cout << endl;     } }   The declaration in .h file is the following  template <typename T> void print2dvector(std::vector<std::vector<T> > v);   Here is how I use it,  print2dvector<int>(vec_of_vec);   The compile stage passes, but failed in linking stage. The error is the following:  Undefined symbols for architecture x86_64:   "void print2dvector<int>(std::__1::vector<std::__1::vector<int, std::__1::allocator<int> >, std::__1::allocator<std::__1::vector<int, std::__1::allocator<int> > > >)", referenced from:    spiral_matrix_ii_Challenge::Execute() in spiral_matrix_ii.o ld: symbol(s) not found for architecture x86_64 clang: error: linker command failed with exit code 1 (use -v to see invocation)   Please let me know if I miss anything conceptually in implementing this.


How do I solve: $$ e^{4z}+e^{3z}+e^{2z}+e^z+1=0 $$  I'm getting lost on where to start. I tried using the definition $$ e^z=e^x(\cos(y) +i\sin(y))  $$  But that doesn't seem to do me any good. I also tried using complex powers, but I seem to just be going in circles. Any suggestions?


What are the criterias to make a question a duplicate question?

I've posted , and then I've got a answer that I considered as the answer to my question. This answer was upvoted by four people. And then my question was considered as a duplicate of . The new question has an answer with one upvote.  So my oldest question was considered as a duplicate of a newest question on what base?


How to Speed Up Booting Time ? (Bypass Grub)

I recently installed Ubuntu 16.04 as my Default and only OS. Whenever I boot up, A Grub Menu Appears and I need to choose a option manually. Since every time my only option will be 'Ubuntu' Therefore I want that My Laptop should directly boot into Ubuntu without asking it.  Is there a way to speed up this process and disable Grub?


vim and tmux are conflicting. How can I fix this?

I'm having a painful experience with tmux.  I'm using solarized in vim but when I run tmux then my vim configuration does not work. It's as if solarized is not configured in my .vimrc.   Out of tmux all is fine! Using tmux using vim hurts my sight....    What do I need to do?


What graphics packages are there for creating graphics in LaTeX documents?

What packages do you use and recommend for creating graphics in your LaTeX documents?     As this is a community wiki post, please add your package to the accepted answer (or add a comment, and someone with >100 rep will add it to the CW answer), and include a brief description of what differentiates it from others and how it can be used (GUI drawing tool which generates code, type in raw text, or generates image for inclusion in document).   We'll eventually sort these answers under headings.


how would one implement a back-button as a commandbutton that works universally? with back button i don't mean the browser-button, but rather a button that sits somewhere on the page. it is not always possible to use the Post-redirect-get pattern.  its quite impractial to pass around the information on every single where the button should point to.  is there maybe a reserved keyword for a navigation rule that points to the last navigation rule applied?


So I have this code:  //HashTable.hpp:   template <class dataType>     class HashTable     {     public:      //Something     public:                                                         HashTable();                                                         HashTable(unsigned int & tableSize);   //HashTable.cpp:  #include "HashTable.hpp"   template <class dataType> HashTable<dataType>::HashTable() {  }   Now, in main() body I just instantiate an object HashTable<int> hTable. When compiling with g++, I get this error :  `EntryPoint.cpp:(.text+0x1f): undefined reference to `HashTable<int>::HashTable()  '  collect2: error: ld returned 1 exit status`   What causes this problem? I recall I've hit this wall a few months ago when doing some templated data structures, but I just quick-fixed it in an error-prone way by including the file.cpp in the entry point's .cpp file. How can this be solved in a clean way? I've tried creating the object files and linking them individually, but I just get the same error. This specific problem frustrated me in such a way(lost > 10 hours researching it) that I've just stopped doing templates. I do not want to force the functions as inlines, as that's a very messy way of solving this. Also, I would avoid including HashTable.cpp instead of HashTable.hpp, as this overrides the concept of header files. I want my class to be as abstract as possible, so I can use it with all data types that I will later create.    Also, I do know that this can be solved by explicit instatiation, but I want to be able to use it with any types without having to "bloat" the code.


I'm using Ubuntu 12.04, and when I rigth click on a my flash drive icon (in the Unity left bar) I get two options that have me confused: eject and safely remove.  The closer I came to an answer was , which concludes that (for a flash drive) they are both equal and also equivalent to use the umount command. However, this last assertion seems to be false.  If I use umount from the console to unmount my flash dive, and then I use the command lsblk, I still see my device (with nothing under MOUNTPOINT, of course). On the other hand, if I eject or safely remove my flash drive, lsblk does not list it anymore. So, my question is, what would be the console command/commands that would really reproduce the behaviour of eject and safely remove?


Is this an abnormal rate of spoke breakage?

I just broke a spoke and this is the fourth spoke I've broken in the last 12 months.  This one was very puzzling because it came at the very end of an easy 30 mile (48 km) ride.  I was pedaling very slowly into my driveway when it snapped.   All four have been on the drive side of the rear wheel.  This is a Specialized Allez, one year old, with factory wheels.  I weigh 175 lbs (79 kg) and ride about 2000 miles (3218 km) per year.  Just recreational riding on good road surfaces.  Is this an abnormal rate of breakage?    And if it is an abnormal rate of breakage, what should I do about it?  EDIT:  I took the wheel into the LBS today. They didn't seem surprised by 4 broken spokes in a year, but everyone else is, so I'm going with everyone else. The mechanic checked the tension and they were all correct with one slight exception, so that's not the issue. The wheels are factory wheels and not exactly top flight. The spokes are 1.2 mm rather than 2 mm, so pretty thin. And they're 28 spokes per wheel, so that's cutting it even thinner from what I can gather.   Rebuilding the wheels is $125 each, so that's just not worth it. I can find much better wheels for not much more, so I'm on Amazon looking at wheels while trying not to deplete my life savings. (What some people will pay for wheels boggles the mind.)  I'll have them fix the spoke and check the tensioning so I can sell them and ride until I get replacements.   Gotta buy the tools and learn to replace spokes and true wheels....


Is every separately continuous function on $R^2$ continuous?

My friend asked me this question a few days ago. I felt it's not right but couldn't find a single counterexample. Any comment is appreciated.


shortcut to switch between virtual machine and host operating system?

okay so I have windows 8 and am running Lubuntu as a VM using vmplayer. I have my laptop hooked up to an external monitor so I have the VM full screen on my laptop and windows 8 on the monitor. What I want is, suppose I have a word document opened up in windows 8 but I'm typing in my VM right now and I want to quickly switch to the word document in windows 8, is there a keyboard shortcut / way to create a keyboard shortcut to switch between the VM and host operating system? Because moving the mouse and clicking between the VM and host operating system is getting a bit annoying.


When I play a FPS with my wireless mouse I feel that the game reacts more slowly than my movements. Is a wireless mouse less reactive than a classic mouse? Is there a loss of performance with wireless mouse? What is the latency of a classic mouse or wireless mouse? How can I test that?


Batch resize vertical photos to a square without cropping using a blurred background

I have about 3000 vertical images that I need resized to 600x600 pixels each. I've compressed a few using Photoshop where I have duplicated the image and then Gaussian blurred it to cover the background like you see in the image below.    I believe this is how Instagram works with vertical images.  Can I program Photoshop to do this automatically or is there any other software? All the images are in a single folder.  If the blur background isn't possible a light shade of grey would do too.


Where to ask for a specific brand of food

I'm looking for a brand of cookies from my childhood. On which Stack Exchange site should I ask?


totally portable ubuntu installation on flash drive?

is it possible to install ubuntu on a flash drive so that i can essentially plug it into any computer and have my desktop, software and files there ready and waiting for me and doesn't leave anything on the PC i was using once it is unplugged?  If it can, can anyone point me towards a guide for doing this please. thanks for the help in advance.  I've never properly used linux before so i apologize if this is a noob question.


How to get file name without extension in file upload using java script

i am going to upload file using file upload control in asp.net . now i want to get file name without extension using java script . i want to validate file name should be only integer format   $(function () {     $('#<%=File1.ClientID %>').change(function () {          var uploadcontrol = document.getElementById('<%=File1.ClientID%>').value;     }) })


I authorized access to my account by an application that turned out to not work.  Now I want to remove the authorization in case it was malicious.  How could I do this?


Content 100% height between header and footer

I've been seeing a lot of questions about this, but none of them got me a nice solution to this problem. It's the typical no scroll intro page. The header can have x pixels but the footer is gonna be responsive (will be taller in tablets and mobiles). I can't really get my wrapper to be 100% height of the space between header and footer without pulling my footer outside and then centering vertically the content in the wrapper.  Any solution?  Thanks in advance


Often when I am on a flight, nearly every sentence I hear from the flight attendants contains an unnecessary emphatic auxiliary in its main clause; that is, an altogether unnecessary do or unnecessary emphasis on other auxiliaries:     We do apologise for the delay, which was due to technical issues, but we will be taking off shortly, and we do hope you enjoy the flight. We do ask you to fasten you seatbelt now, and if you do have any questions, we do hope you won't hesitate to ask us.   What is the purpose of this constant emphasis? My guess is it's supposed to somehow elevate their language to a higher register, but why do flight attendants in particular seem so fond of this?


I've come across the following sentence in a book:  “I wanted to learn everything I could about it from whomever in the country might have specialized knowledge of it.”  I know that the whomever is the object of the preposition from (hence whom). However, isn't it at the same time the subject of the subordinate clause? Therefore, should it not be whoever? (Like in: “I was escaping from I don't know what.” NOT “I was escaping from me don't know what.”) In my view, the sentence would be more elegant if it read:  “I wanted to learn everything I could about it from whoever in the country might have specialized knowledge of it.” “I wanted to learn everything I could about it from whomever in the country.” “I wanted to learn everything I could about it from whomever in the country who might have specialized knowledge of it.” “I wanted to learn everything I could about it from whomever in the country with specialized knowledge of it.”


Acount suspension reason is only shown on the main site profile not meta

I've anonymized the affected user profile, but came across this after seeing a comment on another meta question saying that the reason was visible on the profile; but initially not being able to find it because i was looking at the suspended users meta profile.


not Install DKMS package from PPA | how i install it

this command is not run on my pc:- sudo add-apt-repository ppa:morphis/anbox-support duggal@duggal-X556UQK:~$ sudo add-apt-repository ppa:morphis/anbox-support [sudo] password for duggal:     More info: https://launchpad.net/~morphis/+archive/ubuntu/anbox-support Press [ENTER] to continue or Ctrl-c to cancel adding it.  Hit:1 http://dl.google.com/linux/chrome/deb stable InRelease                    Ign:2 http://ppa.launchpad.net/morphis/anbox-support/ubuntu focal InRelease     Hit:3 http://in.archive.ubuntu.com/ubuntu focal InRelease                       Hit:4 http://in.archive.ubuntu.com/ubuntu focal-updates InRelease               Hit:5 http://packages.microsoft.com/repos/vscode stable InRelease               Hit:6 http://in.archive.ubuntu.com/ubuntu focal-backports InRelease             Err:7 http://ppa.launchpad.net/morphis/anbox-support/ubuntu focal Release         404  Not Found [IP: 2001:67c:1560:8008::15 80] Hit:8 http://security.ubuntu.com/ubuntu focal-security InRelease                Hit:9 https://debrepo.freedownloadmanager.org bionic InRelease                  Reading package lists... Done E: The repository 'http://ppa.launchpad.net/morphis/anbox-support/ubuntu focal Release' does not have a Release file. N: Updating from such a repository can't be done securely, and is therefore disabled by default. N: See apt-secure(8) manpage for repository creation and user configuration details.  it gives me the error


Best basic algebra examples to show students that proof by example is not sufficient

Often, students will try to 'prove' a propositon by checking some examples and 'concluding' that it will be true for all $n \in N$.   I'm looking for some good, non-trivial examples from highschool and lower college mathematics showing that checking a finite number of cases is generally not sufficient. There is already a similar thread with examples from higher level math ().  The best non-trivial example I currently have to show this fallacy is:  3 is odd and prime 5 is odd and prime 7 is odd and prime 11 is odd and prime 13 is add and prime   therefore, all odd numbers are prime. :/


In an episode of How I Met Your Mother, Marshall addresses the following sentence to Kim Kardashian: "You're right, super hot lady who my wife keeps telling me why you're famous but I keep forgetting."  This sentences sounds technically "incorrect" - usually when there's a relative pronoun like "who", the antecedent is not restated. E.g., we'd say "lady who is famous" rather than "lady who she is famous." But in Marshall's sentence it seems like there's an overabundance of subjects.   I myself probably use similar sentences regularly, simply because in English it seems that there is no good alternative. Is there a better way of stating Marshall's sentence? Any insights into this type of usage?


In a few spots I got this to work  ls -rt /path/to/log/file/ | tail -1 | xargs tail -f   But I can't figure out why it won't always work (This is quick fix until I get the log rolling fixed here)


I'm an American living in France, and I want to play Magic the Gathering. Would it be a problem if I buy English printed cards to play in FNM and official tournaments here? Should I just stick to French printed cards since English printed cards may not be allowed?


How to get from Heathrow Airport to King's Cross, London?

My wife and I will be arriving in London via Heathrow Airport (LHR) and are staying at a hotel near King's Cross station. So, we were wondering what the best (which means fastest but also easiest when carrying two large pieces of luggage and two carry-ons) way to get from LHR to King's Cross?  I gather that, with only one changeover, we can take the Tube. However, in the interest of other passengers, we thought it would be best to take a taxi, or maybe a bus?  Thoughts?


Help with $\lim_{x\rightarrow +\infty} (x^2 - \sqrt{x^4 - x^2 + 1})$

$\lim_{x\rightarrow  +\infty} (x^2 - \sqrt{x^4 - x^2 + 1}) = ?$  I don't know how to solve the indetermination there... is it possible to rearrange the expression in brackets in order to use L'Hospital or Taylor Series?


How can I install Broadcom drivers on Ubuntu?

This is my first time installing an Ubuntu system onto my laptop which is a Dell Inspiron 6400. It used to run Windows XP, and when installing Ubuntu it said that the wired network was detected and was able to install new updates needed for the system.  Whenever the system was installed and I tried to connect to the internet I couldn't. I don't think I have a Broadcom driver installed, and I have tried to install it but I get confused on bad tutorials on YouTube. Can anyone give me step by step instructions of how to get the drivers from my other computer which has wireless access and put them on my Inspiron and what to do from there.  Output of lspci:  00:00.0 Host bridge: Intel Corporation Mobile 945GM/PM/GMS, 943/940GML and 945GT Express Memory Controller Hub (rev 03) 00:02.0 VGA compatible controller: Intel Corporation Mobile 945GM/GMS, 943/940GML Express Integrated Graphics Controller (rev 03) 00:02.1 Display controller: Intel Corporation Mobile 945GM/GMS/GME, 943/940GML Express Integrated Graphics Controller (rev 03) 00:1b.0 Audio device: Intel Corporation NM10/ICH7 Family High Definition Audio Controller (rev 01) 00:1c.0 PCI bridge: Intel Corporation NM10/ICH7 Family PCI Express Port 1 (rev 01) 00:1c.3 PCI bridge: Intel Corporation NM10/ICH7 Family PCI Express Port 4 (rev 01) 00:1d.0 USB controller: Intel Corporation NM10/ICH7 Family USB UHCI Controller #1 (rev 01) 00:1d.1 USB controller: Intel Corporation NM10/ICH7 Family USB UHCI Controller #2 (rev 01) 00:1d.2 USB controller: Intel Corporation NM10/ICH7 Family USB UHCI Controller #3 (rev 01) 00:1d.3 USB controller: Intel Corporation NM10/ICH7 Family USB UHCI Controller #4 (rev 01) 00:1d.7 USB controller: Intel Corporation NM10/ICH7 Family USB2 EHCI Controller (rev 01) 00:1e.0 PCI bridge: Intel Corporation 82801 Mobile PCI Bridge (rev e1) 00:1f.0 ISA bridge: Intel Corporation 82801GBM (ICH7-M) LPC Interface Bridge (rev 01) 00:1f.2 IDE interface: Intel Corporation 82801GBM/GHM (ICH7-M Family) SATA Controller [IDE mode] (rev 01) 00:1f.3 SMBus: Intel Corporation NM10/ICH7 Family SMBus Controller (rev 01) 03:00.0 Ethernet controller: Broadcom Corporation BCM4401-B0 100Base-TX (rev 02) 03:01.0 FireWire (IEEE 1394): Ricoh Co Ltd R5C832 IEEE 1394 Controller 03:01.1 SD Host controller: Ricoh Co Ltd R5C822 SD/SDIO/MMC/MS/MSPro Host Adapter (rev 19) 03:01.2 System peripheral: Ricoh Co Ltd R5C592 Memory Stick Bus Host Adapter (rev 0a) 03:01.3 System peripheral: Ricoh Co Ltd xD-Picture Card Controller (rev 05) 0b:00.0 Network controller: Broadcom Corporation BCM4311 802.11b/g WLAN (rev 01)   Output of sudo lshw -c network:    *-network                       description: Network controller        product: BCM4311 802.11b/g WLAN        vendor: Broadcom Corporation        physical id: 0        bus info: pci@0000:0b:00.0        version: 01        width: 32 bits        clock: 33MHz        capabilities: pm msi pciexpress bus_master cap_list        configuration: driver=wl latency=0        resources: irq:16 memory:efdfc000-efdfffff   *-network UNCLAIMED        description: Ethernet controller        product: BCM4401-B0 100Base-TX        vendor: Broadcom Corporation        physical id: 0        bus info: pci@0000:03:00.0        version: 02        width: 32 bits        clock: 33MHz        capabilities: pm bus_master cap_list        configuration: latency=64        resources: memory:ef9fe000-ef9fffff


Can't download facebook in my new iPhone 3GS

I bought a new IPhone 3GS and can't download Messenger, Facebook, hike etc. Why?  How to download?


How to show that the commutator subgroup is a normal subgroup

It is suggested as an exercise in Serge Lang's book "Algebra" to show that the commutator subgroup $G^c$ of a group $G$ is a normal subgroup.   I'd like to do that but I am afraid I need help,   I think the first thing I need to figure out is how a general element in the commutator subgroup looks like, so that I can check that the defining condition for normality is satisfied.  That is, supposing for a moment that a general element in $G^c$ is denoted by $g$, I need to show that $aga^{-1} \in G^c,$ for all $a \in G$.  But here I get stuck, first because I am unsure how to write a general element in $G^c$ - a simple product in $G^c$ is of the form $xyx^{-1}y^{-1}aba^{-1}b^{-1}$ where $a,b \in G$. I cannot see a way to simplify this - I am sure there is one, but somehow I am blind today.  The second thing then is, even if one tries out the conjugation of a simple element like $xyx^{-1}y^{-1}$ in $G^c$, again not simplification offers itself easily I think .. what am I missing ?  An alternative would be to find a homomorphism of $G$ whose kernel is precisely $G^c$ - here I tried to think of this as a map $G \times G \to G$ but whatever I cook up is not a homomorphism.  Thanks for your hints !!


FFMPEG scale video to 720px, add black fields at the top and bottom and output 720x1280 (portrait)

How to do that? I need a fast method to make Instagram moments of ready videos without using video editor.


Texas Holdem: How to Score this Hand - Single Pair, 3 kickers

I have a question for you. It's a question that came up last night in a poker game and is still being debated by the group. Some say split, some say one winner. Please let me know how you would score this hand (see pic below). Please tell me who won, or if there was a tie, and also what the series of cards would be for the winning hand or tie. Also, if you're aware of any game variations that are played that would make both sides of the debate right (unlikely).   I'm not going to tell you what I think, because I don't want to bias your ruling. Just trying to get to the truth here.   Thanks so much!


Can creatures without hands (and as a consequence fingers) use rings?

Pretty much what it says on a label. I have a monster for my next adventure that has a pretty interesting ring in his treasure. Since it is intelligent, and would be able to use the ring, I don't see why the ring should be lying there in a chest waiting to be looted.  Monster would use the ring, if it only had hands or even fingers. Hold a second, are fingers even necessary in 5e?  For reference, assume it only has grasping / manipulating tentacles like a  (although it is not one); Said tentacles are very flexible, capable of fine manipulation, and have varying thickness.


I've come across a couple of videos where some interesting sounds are produced using ice.  (Click on the images to see the video.)      Here, they drop a block of ice into a deep crevice and as the block falls, you can hear some strange sounds. These sounds remind me of some sound effects in old cartoons and sci-fi movies. The pitch of the sounds start high and end up low. Is this some kind of doppler effect?      Here, there's a man performing 'nordic skating', making the same sounds as he skates on top of a thin ice sheet. Maybe they are caused by the cracking ice. But why does that sound like this?    There are some other videos too, where they skip stones on frozen lakes.    Here the ice makes some high-frequency sounds which correspond to the chirping of birds.  What are these sounds and why do they sound the way they sound?


I'm expecting 0.1 as a result but:  In [1]: 0.3 / 3  Out[1]: 0.09999999999999999   Tried with Decimal, nothing changed.  In [2]: from decimal import Decimal In [3]: Decimal(0.3) / Decimal(3) Out[3]: Decimal('0.09999999999999999629925658458')   What should I have to do to get correct result?


Why is $\sin : \mathbb{R} \to [-5,5] $ different from $\sin : \mathbb{R} \to \mathbb{R}$?

My teacher says these two functions are different, why though?  $$\sin : \mathbb{R} \to [-5,5] \tag{1}$$  $$ \sin : \mathbb{R} \to \mathbb{R} \tag{2} $$  Both have the same domain and range. What difference does changing the codomain make here, so long as I keep the codomain as a superset of the range?  More generally speaking, $f : A \to B $ and $f: A \to C$ where $B$ and $C$ are the codomain of the same function $f$ and are supersets of range of $ f$  What difference would that make? How would changing the codomain (in this case) mean the functions are different? Isn't the function $f$ the same?


Compiler fails to find right function overload

I have a small base class that defines 3 overloads for a function. Overload A calls overload B which is pure virtual, and its implementation in the derived class calls overload C. My complete code is as follows: struct Base {         int func(int a) {return func(a, a+1);}         int func(int a, int b, int c) {return a+b+c;}         virtual int func(int a, int b)=0; };  struct Derived : public Base {         int func(int a, int b); };  int Derived::func(int a, int b) {         return func(a,b,a+b); }  int main(int argc, char* argv[]) {         Derived d;         d.func(1);         return 0; }  This code yields the errors: test.cpp: In member function ‘virtual int Derived::func(int, int)’: test.cpp:12:21: error: no matching function for call to ‘Derived::func(int&, int&, int)’    12 |  return func(a,b,a+b);       |                     ^ test.cpp:11:5: note: candidate: ‘virtual int Derived::func(int, int)’    11 | int Derived::func(int a, int b) {       |     ^~~~~~~ test.cpp:11:5: note:   candidate expects 2 arguments, 3 provided test.cpp: In function ‘int main(int, char**)’: test.cpp:17:10: error: no matching function for call to ‘Derived::func(int)’    17 |  d.func(1);       |          ^ test.cpp:11:5: note: candidate: ‘virtual int Derived::func(int, int)’    11 | int Derived::func(int a, int b) {       |     ^~~~~~~ test.cpp:11:5: note:   candidate expects 2 arguments, 1 provided  Why does the compiler fail to find the correct overload twice? (once in the call to overload C in the derived class, and once when calling overload A in the main)


Can I play Destiny without PlayStation Plus?

Today I went to a store to buy Destiny for PS4. I have been played Destiny in the demo 1 month ago. I play just a few hours per week and I don't want have the PlayStation Plus signature.   At the Store the guys advise me to play Destiny I must have the PlayStation plus signature to play this game.   I would like know is it true, why I'm not able to play by myself?


This is a follow-up question to , and is somehow related to   However, my question does not concern the reviews I receive for the papers I submit, but concerns the reviews I write for papers I have been assigned. Since the whole process is done under confidentiality, it is not clear who owns the copyright on a review I wrote, and what does the review include.   For instance, let us assume that X is member of a PC of a conference Y, and assigns to me a review of a paper Z, written by A and B (assuming it's not a double-blind). Can I publish on my blog: "Here is my review for Y, asked by X, on the paper Z, written by A and B"?   I think that there are two points here:    Is it legal? (for instance, publishing the camera-ready version of a paper might be illegal due to the copyright transfer, would it be also the care here?).  Is it ethical? (who should I ask in order to do so? X? Y? A and B? everybody?).    EDIT: There is been several comments/answer wondering why I would like to publish a review I wrote. To give a bit of background of this question, I believe that the current reviewing system, created when the academic community was small and there was no Internet (i.e. no easy access to information), might not be the best, although clearly working. This is for me a very interesting debate, but somehow out of the scope the Q&A format of Academia SE, which is why I tried to focus on my question on whether it was possible to do so, not if it was the best thing to do in the current system (and just to be clear, I don't plan to do it, but I just like to know what are my options). Anyway, thanks for the answers bringing a different light on this debate.   EDIT 2: After seeing the update in Jeff's answer, I just realised that I didn't make it explicit that I was talking about reviews after the reviewing process. Jeff says that it's ok if the paper is accepted, and although I clearly understand the argument of why I shouldn't publish a review of a rejected paper, the question still holds: by publishing a review of a rejected paper, I publish the information that these authors submitted this paper to this conf/journal, which is supposed to be confidential between the authors and the editors. Would I break any rule by doing so?


Can we have an "unanswered" option on the Profile > Questions page?

After a while you start getting to the point where you've asked a lot of questions - finding the ones that don't have an answer starts to become a little laborious. I currently only have 11 pages of questions but this is going to continue growing over time. Some of these questions don't have an answer.  From a usability point of view, it would be nice to have an "unanswered" option alongside the existing "votes", "activity", "newest" and "views" options on users/current?tab=questions.  The way I would expect this to behave is that selecting this view would result in all questions that have not got an accepted answer would be listed, in date sorted order (newest to oldest). This would include any questions that have answers posted on them (regardless of the number of upvotes on the answer). Think of it as a checkmark filter.  I can't imagine it would be particularly difficult to implement and there's plenty of space to fit an additional button here without having to move anything around.   Would this be possible?  Note:  has been asked many years ago without defining exactly what was needed in specifics, and it doesn't have an official response from Stack Exchange on it, this is a feature request after all.


If $x$, $y$, $z$ are in arithmetic progression, show that $\frac{\sin x + \sin y + \sin z }{\cos x + \cos y + \cos z} = \tan y. $

Show that if $x, y,$ and $z$ are consecutive terms of an arithmetic sequence, and $\tan y$ is defined, then  $$\frac{\sin x + \sin y + \sin z }{\cos x + \cos y + \cos z} = \tan y. $$  I'm not sure what trig identities I would use and how to use them.  Could I get some help?  Thanks.


Explanation and proof of the 4th order Runge-Kutta method

The 4th order Runge-Kutta (RK4) method is a numerical technique used to solve ordinary differential equations (ODEs) of the following form $$\frac{dy}{dx} = f(x,y), \qquad y(0)=y_0$$ It gives $y_{i+1}$ in the form $$y_{i+1} = y_i+(a_1k_1+a_2k_2+a_3k_3+a_4k_4)h$$ where the constants are found to be: $$y_{i+1} = y_i+\frac{1}{6}(k_1+2k_2+2k_3+k_4)h$$ and: $$\begin{aligned} k_1 &= f(x_i, y_i)\\ k_2 &= f \left(x_i+\frac{1}{2}, y_i+\frac{1}{2}k_1h \right)\\ k_3 &= f \left(x_i+\frac{1}{2}, y_i+\frac{1}{2}k_2h \right)\\ k_4 &= f(x_i+h, y_i+k_3h) \end{aligned}$$ I also learnt that these are derived from the first four terms Taylor series: $$y_{i+1}=y_i+f(x_i,y_i)h+\frac{1}{2!}f'(x_i,y_i)h^2+\frac{1}{3!}f''(x_i,y_i)h^3+\frac{1}{4!}f'''(x_i,y_i)h^4$$ These are the things that I understood. However, here are what I cannot:  I cannot see why this method "works"? How are the $a_ik_i$ terms derived and computed from the Taylor series? What justifies or proves this result?  Please note that I have seen many articles on these things things, but none of them contained a full proof whatsoever... I would also much like to get some examples where the f function is actually a function of both x, y not only x. Could you please send me some links with further advanced and concise links of this question?


Use Windows license from physical machine on hosted VM within linux

I have a bunch of Dell machines that came with BIOS-injected Windows 7 licenses. They have all been upgraded to Windows 10 and now show as having a valid "digital entitlement" license.  These are powerful machines that are normally booted into Ubuntu (dual-boot) as development environments.   We have a corporate Active Directory and I'd like to have the machines run a Windows VM on Virtualbox so they can be domain joined and easily access the Windows managed network resources when they need to. Physically rebooting the whole machine into Windows is too painful as it requires my devs shutting down all their other development VMs and effectively interrupting all their other work.  Is there any way I can use the valid Windows license (in the BIOS) that these machines have within a VM? I should mention that my devs aren't interested in having Windows as the physical host OS.


Finitely presented group with fewer relations than generators.

I some how feel that, any finitely presented group with less relations than generators has to be an infinite group.  In one of my questions, in an answer I have seen a group which is finitely presented but it is not finite.  $G=\langle a,b\mid a^2=b^2=1\rangle$ this group is infinite. I see that if there is at least one more relation in between $a$ & $b$ then the group is finite.     I claim that if there are fewer relations than generators of a finitely presented group, then the group has to be infinite.   I would like to see is it true in general??  Is any finitely presented group with fewer relations than generators an infinite Group?  Please suggest some idea to see if this is true/false?


What is the difference between .prototype and this. in defining methods in Javascript?

These two examples aren't making any difference. But I just want to know what is the use of object.prototype property. And tell me which is one is the standard procedure in Object Oriented Programming in Javascript. Any illustration would be nice.   var Person = function(){    this.name = "John Doe"  }  Person.prototype.sayHello = function(){    console.log( "Hi, I'm "+this.name ); }  var John = new Person();  John.sayHello();   and here is another example without object.prototype property  var Person = function(){    this.name = "John Doe";    this.sayHello = function(){      console.log( "Hi, I'm "+this.name );    }  }  var John = new Person();  John.sayHello();


How to use "when" vs. "while" on the following occasions?

Please have a look at these sentence pairs:           When I worked as a teacher, I met a good friend.    While I was working as a teacher, I met a good friend.         When I had a dream, I thought of the idea.   While I was having a dream, I thought of the idea.         Which ones are correct? And why?


How to pull email address and password from text file with CMD?

I have a text file named file.txt Which contains,  Combo: testing123mail@gmail.com:password As Combo:  abcdefghijklmnopqrstuvwxyz@gmail.com:ajfbdf some text here some more text here As Combo: hadvsfhia@ahfjbadj.com:password@1 some random text here iloveu@gmail.com:passypassyword123 goldenmammy@hotmail.com:youtube123   I am running the below code, to filter only mail:pass from the above text file file.txt  for /f "tokens=3" %%a in ('type file.txt^|find "As Combo:"') do >>mail.txt echo %%a for /f "tokens=2" %%b in ('type file.txt^|find "Combo:"') do >>mail.txt echo %%b for /f "tokens=1" %%c in ('type file.txt^|find ":"') do >>mail.txt echo %%c   Expected Output in mail.txt,  abcdefghijklmnopqrstuvwxyz@gmail.com:ajfbdf hadvsfhia@ahfjbadj.com:password@1 testing123mail@gmail.com:password iloveu@gmail.com:passypassyword123 goldenmammy@hotmail.com:youtube123   But, am getting actual output is,  abcdefghijklmnopqrstuvwxyz@gmail.com:ajfbdf hadvsfhia@ahfjbadj.com:password@1 testing123mail@gmail.com:password Combo: Combo: Combo: As As iloveu@gmail.com:passypassyword123 goldenmammy@hotmail.com:youtube123   Note: The mail id and passwords will be differ in different text file. Above given mail id and passwords are typed by me randomly for example.  Kindly fix my code and help to get expected output. Thanks in advance.


Removing a manually installed package and now reporting not installed but won't install

I manually compiled mono from the /tmp directory (4.9.1) and found that it was too unstable for me, so wanted to revert back to the install from the repos. I foolishly did a reboot before doing this, so the compiled code in /tmp had gone. So, I thought I'd remove the directory of where mono is installed and mark the package mono-complete as being automatically installed again.  (Un)Surprisingly, this did not work. Now, if I do a which mono it reports that it isn't installed. If I mono I get the same message. However, when I do an apt install mono-complete or mono-devel it reports mono-complete is already the newest version.  I have checked in the env and there is no reference to mono.  How can I sort this mess out and get back to being able to install mono from packages.


How can I extract menthol powder from fresh mint/peppermint?

I have peppermint/mint growing in my garden backyard. I want to make Ice Cream for children and they are asking for some flavour paan ice cream in Hindi (mint ice cream) and for that I want Menthol powder to mix into plain ice cream. How can I make Menthol Powder from Mint/Peppermint Leaves?


How many ancestors alive 1000 years ago does a person have on average?

I was thinking about something the other day (that is probably stupid), and thought this would be a good place to talk about it.  If someone wanted to draw its family tree over the last 1000 years, he'd write a binary tree with a depth of about 40 (counting 25 years on average between each generations). This tree would have 240 leaves, or about 1012 ancestors on the deeper level. That is obviously much more than the total world population and a stupid figure when you think about it.  The only explanation that I can think of is that a real genealogy tree must have "linked" branches at several levels that change the actual number of ancestors. Anyway, for an average person, how many ancestors would that make? Could one assume that all or nearly all of the persons that lived in its country or world region a 1000 years ago would be part of its ancestors?


Why does df show Available 0 when 1K-blocks minus Used is greater than 0?

Why does it show 0 in the available column?  [root@server log]# df Filesystem           1K-blocks      Used Available Use% Mounted on /dev/sda2              4128448   4096484         0 100% /   It's an ext3 filesystem.


How do I start conky when ubuntu starts up?

I'm using Ubuntu 12.04 and installed the Conky system monitor, and start it with the conky command. I added this code on startup-applications but nothing works. How do I start conky when my Ubuntu starts up? Is it possible to start multiple Conky themes on startup?


Spherical Cap of Riemann sphere under stereographic projection

Let $\mathbb{S} = \{ (X,Y,Z) \in \mathbb{R}^3 :X^2 + Y^2+Z^2=1\}$ denote the Riemann sphere. The following problem is taken from Gamelin "Complex Analysis" chapter one:     What is the image of the spherical cap $ C := \{(X,Y,Z) \in \mathbb{S} : A \leq X \leq 1\}$, where $A$ is some fixed real number between $-1$ and $1$, under the stereographic projection $ \pi(X,Y,Z) = \frac{X+iY}{1-Z}$?   Here is my work so far:  ( The case $A=1$ is trivial, so assume $A <1$)  We want to find $\pi(C) = \{z \in \mathbb{C} \mid \exists(X,Y,Z) \in C: \pi(X,Y,Z) = z \}= \{z \in \mathbb{C} \mid \pi^{-1}(z) \in C\}$, where the last equality holds by $\pi$ being a bijection. Write $z=x+iy$.  Here, $ \pi^{-1}(z) \in C\iff A\leq \frac{2x}{1+x^2+y^2} \leq 1 \iff (\star) :A \leq \frac{2x}{1+x^2+y^2}$, since the inequality $2x \leq 1+x^2+y^2$ holds for all $x,y \in \mathbb{R}$.  $A=0$: $( \star)$ reduces to $ 0 \leq x$, so in this case the image is $\{z \in \mathbb{C} \mid \Re(z) \geq 0 \}$.   $A >0$: Since $A \neq 0$ in $(\star)$ we have,  $ \frac{2x}{1+x^2+y^2} \geq A \iff Ax^2-2x+Ay^2+A \leq 0 \iff (x-\frac{1}{A})^2 +y^2 \leq \frac{1}{A^2}-1$. Thus the image is the interior and boundary of the circle centered at $\frac{1}{A}$ with radius $\sqrt{\frac{1}{A^2}-1}$. Note $\frac{1}{A^2}-1 \geq 0$ as $A \in (0,1)$.  $A <0$ : By symmetry and the above, here the image is $ \mathbb{C} / \{ $ interior and boundary of circle centered at  $  \frac{1}{A}$ with radius $\sqrt {\frac{1}{A^2}-1} \}$.  Is my working correct? Many Thanks!


I need to create a bibliography that meets very specific style guidelines not compatible with any packages in LaTeX. Therefore, I need to be able to enter the exact text I want to appear in my bibliography. However, I also want to reuse bibliography entries as I would with BibTeX, keeping a central bibliography in a separate file from my documents.  How can I keep my exact bibliography entries in a database similar to BibTeX so that I will be able to \cite them in my documents? (I do not insist on the command being \cite, but I want it to have the same effect as \cite would in a traditional bibliography.)


Ok! My question is, what is the physical meaning of the vector produced by a cross product?   For instance, in torque, what does the cross product’s resultant vector mean? What does it tell me about the previous two vectors? I know, also, that the vector produced is perpendicular to both the previous vectors, but what does that mean? Again, what does that tell me about my two previous vectors.  I looked up this question online and found one response on Quora:   “A dot product represents things like work, essentially giving a number value to how much two vectors are “cooperating” . . . A cross product is a vector, at right angles to both vectors forming it. It measures essentially how much two vectors are not cooperating, and is a maximum when the two vectors are right angles.”  That sounds in the ball park as to the definition I want, but I need further clarification as to the word “cooperating” (if that person’s explanation is remotely correct). I don’t want a simple definition - I want meaning.   Please help!! Thanks for reading and I hope to have an answer soon!   :-)


Mixed increment operators with logical operators

I have a question concerning pre and post increments with logical operators if I have this code   void main() {int i = - 3 , j = 2 , k = 0 , m ; m=++i||++j&&++k; printf("%d %d %d %d",i,j,k,m);}   knowing that the increment and the decrement operators have higher precedence than && and ||  So they'll be executed first Then the && is higher than means -2||3&&1 which gives the values -2 3 1 1 for the printf    but the output I get when trying on VS2010 is -2 2 0 1   Does anyone have any explanation for that ?  Regards,,


How do I download a CSV file from a web server to a local machine using HTTP?


Accepted answer does not always appear at the top

I just recognised that an accepted answer does not always appear at the top of the other answers (for example ) Sometimes it does, but if I reload the page the two answers change their positions and the accepted answer is at the bottom.


How to use question marks in quotations?

My specific problem right now is whether to use      "What time is it?" she asked.   Or     "What time is it," she asked.   Or something else. But I find myself having issues with punctuation and quotation marks all the time, so I really want to know the general rules around it.


Difference between "I've got a cold" and "I've gotten a cold" in American English

I once heard there is a difference in meaning between these two sentences in AmE. Is there any?  The possible duplicate  does not address this particular case.


Give the remainder of $x^{100}$ divided by $(x-2)(x-1)$.

What will be the remainder obtained when the polynomial $x^{100}$ is divided by the polynomial $(x-2)(x-1)$.  I used remainder theorem but it had no impact in the solution.


Converting a generic argument to an int in java, provided that it is a number

Here's what I've been trying to do, in a nutshell:  class example <T extends Number> {     private int function(T number)     {         int x = (int) number;         ...     }     ... }   Basically, I'm trying to make it so that T is a number so I can convert it to an int inside that function. The problem is that I'm getting an "incovertible types" error, so I must be doing something wrong.


How do you find the distance from a point to the plane when the point and the basis for the plane are given?


Find all $2 \times 2$ matrices $A$ such that $AB = BA$ for every $2 \times 2$ matrix $B$

Find all possible $2 \times 2$ matrices A that for any $2 \times 2$ matrix B,  AB = BA.  Hint: AB = BA must hold for all B. Try matrices B that have lots of zero entries.  I'm clueless as to how to solve this problem. How should I start it? I tried plugging in values for B that "have lots of zero entries" but didn't seem to see anything that could help.


Java - Compare item of String array with a String

I really don't understand what's wrong right now.  String s = "a,b,c,d"; String[] test = s.split(","); System.out.println(test[0]); System.out.println(test[0] == "a");   Console prints:   a false   That doesn't make sense at all. test[0] is "a" and ("a" == "a") is false ?  Excuse me for my bad english. Thanks!


LyX: how to make two "examples" not separated by a different environment?

I use LyX for some time now, but have not figured out how to put two "examples" (or exercises or theorems etc.) one after the other without having to separate them by a different environment.   What happens: say I'm in the "example" environment and finished writing example No 1. I hit enter to start a new paragraph. LyX then allows me to choose a different environment like "standard text" starting from the new paragraph, but I'm unable to start a new example No 2.  I hope someone knows a simple solution.


Can I ask for an earlier UK visa start date after visa issued?

I live in the US and I'm not a US Citizen. Just applied to the UK visa and received my passport back. I was supposed to go on a work project to India early August and on my way back I wanted to stay in London visiting friends. Which is why I put August 7th as a start date. However, the project changed and now it's a week earlier, meaning i will arrive in the UK (Transit) by July 31st. Am i going to be able to entry the UK? Can I change the date of entry? What can I do right now? My flight to India leaves July 22nd.


Proving mathematical induction with arbitrary base using (weak) induction

I attempted a proof of mathematical induction using an arbitrary base case, but was unsuccessful (and hence this question). Below is what I was trying to do and along with my thinking; if anyone can point me in the right direction I'd appreciate it.  The induction I am using: Let $P$ be a property about the natural numbers $\mathbb{N}$ with $0\in\mathbb{N}$, and let $P(n)$ denote the statement that the property $P$ holds for $n\in\mathbb{N}$. Suppose $P(0)$. Furthermore suppose that for each natural number $k$, $P(k)$ implies $P(k+1)$. Then $\forall nP(n)$.  What I am trying to prove: Let $P$ be a property about the natural numbers $\mathbb{N}$ with $0\in\mathbb{N}$, and let $P(n)$ denote the statement that the property $P$ holds for $n\in\mathbb{N}$. Suppose for $n_0\in\mathbb{N}$, $P(n_0)$. Furthermore suppose that for each natural number $k\geq n_0$, $P(k)$ implies $P(k+1)$. Then $\forall n\geq n_0 P(n)$.  My attempted proof: define $Q(n)$ to be $n\geq n_0 \to P(n)$. Then we wish to prove $\forall nQ(n)$. We induct on $n$.  Base case (for ordinary induction): $Q(0)$ is $0\geq n_0\to P(0)$. Since $n_0\in\mathbb{N}$, $0\geq n_0$ implies that $n_0=0$. Since $P(n_0)$, $P(0)$, which proves the base case.  Inductive step: we want to show $\forall n(Q(n)\to Q(n+1))$. To do this, we assume $k\geq n_0 \to P(k)$ and try to show $k+1\geq n_0 \to P(k+1)$.  Since $k\geq n_0 \to P(k)$, we first prove the case where $k\geq n_0$ and $P(k)$. By the hypothesis of the proof, we see that $P(k+1)$, which proves the case for $k+1$.  This is where I am having trouble: For $k<n_0$, I am unable to show the implication for $k+1$.  So my questions would be: (1) is the overall approach for the proof correct? (2) If so, how might I go on to prove the case when $k<n_0$?  Thanks in advance. (This is not homework, by the way.)


On some icons I am seeing a two blue arrows at the top the right pointing towards each other. I first noticed it on the icons on folders which I archived which happened randomly. I archived the folder and the text went blue as expected, then when I went to the folder again the text was black and the folder icon has these arrows. When I just recently installed Office 2007, I noticed the same arrows on the icons for the programs. OS: Windows 10 Pro 64-bit (the latest update: 1115) Application: Microsoft Office 2007 suite and file explorer


I created a new group and user so it can connect to server using SFTP. This user's directory is set to /var/www. Running ls -ld gave me following result:     drwxr-xr-x 4 root sftponly 4096 Aug 12 04:05 /var/www/   sftponly is the group and mysftpuser is the user which is part of this group.  I was able to successfully connect using SFTP client but was unable to delete any file inside www. So I ran following command to change permission:     sudo chmod 775 /var/www/   Now running ls -ld gives me following result:     drwxrwxr-x 4 root sftponly 4096 Aug 12 04:05 /var/www/   But now when ever I try to connect to SFTP using user mysftpuser I get error in auth.log     fatal: bad ownership or modes for chroot directory "/var/www"   What did I do wrong and how to fix this issue?  EDIT  sshd_config     Match group sftponly   ChrootDirectory /var/www   X11Forwarding no   AllowTcpForwarding no   ForceCommand internal-sftp