Is there any difference between "student" or "pupil"?
"Pupil" or "Student", what is the correct use?
If $r,s,t$ are prime numbers and $p,q$ positive integers s.t. $\text{lcm}(p,q)$ is $r^2s^4t^2$, then the number of ordered pairs $(p,q)$ is? If $r,s,t$ are prime numbers and $p,q$ are the positive integers such that LCM of $p,q$ is $r^2s^4t^2$, then the number of ordered pairs $(p,q)$ is?  My attempt to the solution:  Let $r^a s^b t^c$ be the LCM where $a=2,b=4,c=2$  Then the cases that arise are  I case   1) $p$ has $r^as^bt^c$ then there are a total of $(2+1)(4+1)(2+1)$ options  II case   1) $p$ has $r^as^b$ or $s^bt^c$,$r^at^c$ then there are total of $(2+1)(4+1)(2+1)(3)$ options.  The answers comes out to be $45*4$ but the answer is $45*5$. Which case am I missing? Asking days badges A couple of months ago, I suggested a set of badges for . The responses were... mixed. The  can be summarized:  In practice, all this would do is encourage people to ask yet more stupid, worthless questions and we have quite enough of that as it is.  We believe that one of the main things holding back many of our beta sites is that when people have questions they aren't in the habit of asking on the site. Even our flagship site, Stack Overflow, doesn't get many questions from its most knowledgeable users. Perhaps they don't have questions, but far more likely they find answers without needing to ask. Our subtle bias against asking (questions =&gt; clueless) means we lose out on what might be our best source of excellent questions. So we went back to the drawing board and designed a badge set that should not encourage worthless questions:  Asked a well-received question on X separate days, and maintained a positive question record.  In order to award badges, we need to define our terms:  positive question record   (total questions - negative questions - closed - deleted)/total questions &gt;= 0.5  It triple counts a question that is downvoted, closed, and deleted. If you ask one that hits that trifecta, you'll need to ask three better questions to dig yourself out. My own record of asking does not meet the criteria:   (44 - 0 - 12 - 12)/44 = 0.4545...  My  looks a lot better; I had a bunch of questions from the beta period that have been subsequently (and rightfully) deleted. With care, I could bring my record into positive territory with 4 questions. The takeaway is that people can't sweep past indiscretions under the rug by deleting them. And they can recover from a bad start as long as they don't ask more bad questions.  well-received question on X separate days A well-received question is one that's open, not deleted, and has a score &gt; 0. If you ask at least one well-received question in a  and none of your questions that day are deleted, downvoted, or closed, you get one more day of credit toward the badge. Whenever the badge criteria is checked, previous asking days are re-evaluated so that there's an incentive to fix downvoted and/or closed questions. The no-deleted-questions criteria is to prevent people from asking several questions at once and deleting any that aren't upvoted or answered to ask another day. (Though this is a losing strategy in the long run.)   My proposed badge names and levels:  Asked a well-received question on 5 separate days, and maintained a positive question record.  Asked a well-received question on 30 separate days, and maintained a positive question record.  Asked a well-received question on 100 separate days, and maintained a positive question record. In addition, since some outstanding individuals ask on more than 100 days, the gold badge may be awarded multiple times. Over on English, Oishi-sama (now a ) would have a remarkable . Bronze and silver badges are only awarded once. We've decided to hold off on multiple awards for now. See the . Neither the names nor the levels nor even the descriptions are set in stone. Please play around with  to get an idea of how the badge works using our public data. Since the query does not account for deleted questions, it's a bit more generous than the actual badges would be. This version of the badge set should encourage a habit of well-received questions over time and encourage people to fix poorly received questions.  I'd like to express my gratitude to the Parenting community for participating in our . I read it in English in the United States, somewhere in the 1990s. I got it off of the big bookshelf in our family room, which means it could be a good bit older; some of the books were my Dad's. At the beginning, a young boy (maybe an early teen?) leaves his house, where he lives with his parent or parents, and takes a test to become a spaceship pilot for the military. Part of the test judges reaction speed, and he fails the test. He later learns (I think when he's approached by an agent of the government) that he "failed" because he has some sort of enhanced fortune that meant that he was actually giving the results before they could be displayed on the screen. At the time, I remember thinking that the book felt a bit like a Star Wars rip-off.  Years later, I read that one of the Star Wars books (probably now Legends) had Luke similarly failing the Imperial Academy test because he gave his answers too quickly, and it amused me that I was uncertain as to which had come first.  I don't remember anything concrete about the cover, although I have a general impression that it was white. Definitely futuristic. My impression was that the boy was wearing a white uniform for the testing and that the government agent who spoke to him had a grey beard, but I might be mixing bits of Star Wars in there. What happens in these end-game situations? This is intended to be a canonical question regarding possible endings of the game.  For each question, assume a single proper strike was made, and note where an improper strike would change the game outcome (beyond an additional point for the opponent).  If the Queen has been covered:     What happens if I pocket my last C/m and the Striker? What happens if I pocket my opponent's last C/m? What happens if I pocket my opponent's last C/m and the Striker? What happens if I pocket both players' last C/m? What happens if I pocket both players' last C/m and the Striker?     If the shot covers the Queen:     What happens if I pocket my last C/m and the Queen? What happens if I pocket my last C/m, the Queen and the Striker? What happens if I pocket my opponents' last C/m and the Queen? What happens if I pocket my opponents' last C/m, the Queen and the Striker? What happens if I pocket both players' last C/m and the Queen? What happens if I pocket both players' last C/m, the Queen and the Striker?     If the Queen is left on the board:     What happens if I pocket my last C/m, leaving the Queen? What happens if I pocket my last C/m and the Striker, leaving the Queen? What happens if I pocket my opponent's last C/m, leaving the Queen? What happens if I pocket my opponent's last C/m and the Striker, leaving the Queen? What happens if I pocket both players' last C/m, leaving the Queen? What happens if I pocket both players' last C/m and the Striker, leaving the Queen? I tried to install ffmpeg in trusty/Ubuntu 14.04 and got the following message:  $sudo apt-get install ffmpeg  Reading package lists... Done Building dependency tree        Reading state information... Done Package ffmpeg is not available, but is referred to by another package. This may mean that the package is missing, has been obsoleted, or is only available from another source  E: Package 'ffmpeg' has no installation candidate   Why isn't the package available? "add/show comments" should dismiss notification What if the hard disk is partitioned into more than 26 sections in Windows? What is the best introductory Bayesian statistics textbook? Which is the best introductory textbook for Bayesian statistics?  One book per answer, please. How do I pull from a Git repository through an HTTP proxy? Note: while the use-case described is about using submodules within a project, the same applies to a normal git clone of a repository over HTTP.  I have a project under Git control.  I'd like to add a submodule:  git submodule add http://github.com/jscruggs/metric_fu.git vendor/plugins/metric_fu   But I get  ... got 1b0313f016d98e556396c91d08127c59722762d0 got 4c42d44a9221209293e5f3eb7e662a1571b09421 got b0d6414e3ca5c2fb4b95b7712c7edbf7d2becac7 error: Unable to find abc07fcf79aebed56497e3894c6c3c06046f913a under http://github.com/jscruggs/metri... Cannot obtain needed commit abc07fcf79aebed56497e3894c6c3c06046f913a while processing commit ee576543b3a0820cc966cc10cc41e6ffb3415658. fatal: Fetch failed. Clone of 'http://github.com/jscruggs/metric_fu.git' into submodule path 'vendor/plugins/metric_fu'   I have my HTTP_PROXY set up:  c:\project&gt; echo %HTTP_PROXY% http://proxy.mycompany:80   I even have a global Git setting for the http proxy:  c:\project&gt; git config --get http.proxy http://proxy.mycompany:80   Has anybody gotten HTTP fetches to consistently work through a proxy?  What's really strange is that a few project on GitHub work fine ( for example), but others consistently fail ( for example). Currently selected indicator's colour in flag summary and help pages, can be the same as the site's colour code Could the Infinity Gauntlet be used to make two people fall in love with each other? I am wondering if there is anything in Marvel comic book canon or in the MCU that says that the Infinity Gauntlet has the power to make someone fall in love with the person wearing the Infinity Gauntlet, or that the wearer of the Infinity Gauntlet can use the Infinity Gauntlet to make two strangers fall in love with each other? Perhaps the combined power of the Mind Stone and the Soul Stone would make two people fall in love. Convergence of cos, sin, tan functions In Radian mode, continually pressing the $\cos$ function of a number causes the result to converge to $x=0.739085133$, a fixed point of $\cos(x)$. Repeating this behavior with the $\sin$ function causes the result to converge to $x=0$, a fixed point of $\sin(x)$.   What happens if this is done using the tan function? It seems that $x=0$ is a repelling fixed point with no convergence in this case.  What would be the best way to explain these results mathematically? How to read a windows registry file using java? Find where java class is loaded from Does anyone know how to programmaticly find out where the java classloader actually loads the class from?    I often work on large projects where the classpath gets very long and manual searching is not really an option.  I recently had a  where the classloader was loading an incorrect version of a class because it was on the classpath in two different places.  So how can I get the classloader to tell me where on disk the actual class file is coming from?  Edit: What about if the classloader actually fails to load the class due to a version mismatch (or something else),  is there anyway we could find out what file its trying to read before it reads it? How to test apex classes with Pagereference? I'm struggling to test a class with pagereference. Following is the class...  public with sharing class redirectOrderPartner{  public String currentRecordId {get;set;} public orders__c orderId {get;set;}  public redirectOrderPartner(ApexPages.StandardController controller) {      }     Public Pagereference go(){      currentRecordId  = ApexPages.CurrentPage().getparameters().get('orderid');      system.debug('---currentRecordId  ---'+currentRecordId  );     orderId = [select id from orders__c where name =: currentRecordId limit 1];      system.debug('---orderid---'+orderId);      PageReference pageRef = new PageReference('/apex/OrderTrackingClass?id='+orderId.id);     pageRef.setRedirect(true);     return pageRef;    }   }   Following is what I tried....    @isTest  public class redirectOrderPartner_TEST  {             static testMethod void Test(){            Account acc = new Account(Name='ABC Corp.');           insert acc;            orders__c tempOrder = new orders__c(name = '0001234567', account__c = acc.id );           insert tempOrder;            Test.startTest();            PageReference pageRef = Page.redirectOrderPartner;           Test.setCurrentPage(pageRef);            ApexPages.Standardcontroller sc = new ApexPages.Standardcontroller(tempOrder);           ApexPages.currentPage().getParameters().put('Id',tempOrder.name);           PW_redirectOrderPartner ec = new redirectOrderPartner(sc);           ec.go();                                   Test.stopTest();       }   } I get the following error message on testing..     System.QueryException: List has no rows for assignment to SObject   What am I missing? Thanks From my old HD (Ubuntu 16.04) I copied ~/.thunderbird and other programs to the new disk with Ubuntu 18.04 installed. All went good. I tried to install Opera. The installation was unsuccessful, a window asking something was held. After that Thunderbird Local Folders -> Inbox (only) was invaded by large icons like this screenshot  Flowers, plants, trucks and others. I restarted but those images are still there. Opera was successfully installed. What can I do to remove them? If $x_1=5$, $x_{n+1}=x_n^2-2$, find $\lim x_{n+1}/(x_1\cdots x_n)$ Is there a single word to describe a solution that hasn't been optimized? Neatest proof that set of finite subsets is countable? I am looking for a beautiful way of showing the following basic result in elementary set theory:     If $A$ is a countable set then the set of finite subsets of $A$ is   countable.   I proved it as follows but my proof is somewhat fugly so I was wondering if there is a neat way of showing it:  Let $|A| \le \aleph_0$. If $A$ is finite then $P(A)$ is finite and hence countable. If $|A| = \aleph_0$ then there is a bijection $A \to \omega$ so that we may assume that we are talking about finite subsets of $\omega$ from now on. Define a map $\varphi: [A]^{&lt;\aleph_0} \to (0,1) \cap \mathbb Q$ as $B \mapsto \sum_{n \in \omega} \frac{\chi_B (n)}{2^n}$. Then $\varphi$ is injective hence the claim follows. (The proof of which is what is the core-fugly part of the proof and I omit it.). What kind of passport do I need when entering the USA? I heard that you need a biometric passport if you want to enter USA. However, my friend has a biometric passport, but no fingerprints in it. Is this enough? And how long has the passport to be valid? Is it okay if it expires on the day after his return date?