I have tried to uninstall tor browser multiple times with no success. When I go into the Ubuntu software uninstaller it doesn't show up. When I right click the tor browser icon and click on show details it will pop up that away. But when I click uninstall, it doesn't do anything. Sometimes it will say it uninstalled it. But then instantly pops up that its currently installed. Also if I cannot install or uninstall anything else in my Ubuntu software. I have tried some terminal commands with no prevail. It keeps saying  sudo apt-get remove --purge tor-browser  [sudo] password for mp********:  Reading package lists... Done Building dependency tree        Reading state information... Done N: Ignoring file 'tor.list^G' in directory '/etc/apt/sources.list.d/' as it has an invalid filename extension E: Unable to locate package tor-browser

In Ubuntu 13.04 I used to use the ppa:upubuntu-com/tor64  PPA to install the 64-bit Tor Browser Bundle. However, in Ubuntu 13.10 it doesn't work anymore. How do I install the Tor Browser Bundle in Ubuntu?


I am writing android program to scan for BLE devices. If scanned device has name of "Pvz2", then I would like to call a function.  Everything would work well but app crashes when I try to compare recently scanned device name to previously defined string. What could be the problem?  final String vardas1="Pvz2";  private ScanCallback mScanCallback = new ScanCallback() {     @Override     public void onScanResult(int callBackType, ScanResult result) {         super.onScanResult(callBackType, result);         BluetoothDevice btDevice = result.getDevice();         String name = btDevice.getName();           if (result.getScanRecord() != null && Sc_on) {             if (name.equals(vardas1))                 // Here I would call the function but this point is never reached             }         }                             ...   Stacktrace of the crash:

What are Null Pointer Exceptions (java.lang.NullPointerException) and what causes them?  What methods/tools can be used to determine the cause so that you stop the exception from causing the program to terminate prematurely?


Ubuntu noob here. How can I speed up boot of this system?  The time after the unit is active or started is printed after the "@" character. The time the unit takes to start is printed after the "+" character.     graphical.target @53.066s └─multi-user.target @53.066s   └─snapd.seeded.service @37.351s +31ms     └─snapd.service @30.360s +6.987s       └─basic.target @29.615s         └─sockets.target @29.615s           └─snapd.socket @29.539s +75ms             └─sysinit.target @29.538s               └─cryptsetup.target @29.497s                 └─systemd-ask-password-wall.path @3.649s                   └─-.mount @3.630s                     └─system.slice @3.649s                       └─-.slice @3.630s

Since upgrading from 14.10 to 15.04 a few days ago the boot time, grub OS screen to login screen, has increased from 12 seconds to about 40. This is my systemd-analyze critical-chain output:  The time after the unit is active or started is printed after the "@" character. The time the unit takes to start is printed after the "+" character.      graphical.target @37.433s     └─multi-user.target @37.433s       └─getty.target @37.432s         └─getty@tty1.service @37.432s           └─systemd-user-sessions.service @35.906s +9ms             └─remote-fs.target @35.904s               └─media-XalnasStorage.mount @35.849s +53ms                 └─network-online.target @35.846s                   └─network.target @11.636s                     └─NetworkManager.service @11.502s +132ms                       └─basic.target @11.487s                         └─sockets.target @11.487s                           └─avahi-daemon.socket @11.487s                             └─sysinit.target @11.485s                               └─networking.service @11.333s +65ms                                 └─apparmor.service @11.269s +63ms                                   └─local-fs.target @11.268s                                     └─media-TStore1.mount @10.331s +936ms                                       └─local-fs-pre.target @10.328s                                         └─systemd-remount-fs.service @10.320s +6ms                                           └─systemd-fsck-root.service @10.303s +15ms                                             └─systemd-journald.socket @151ms                                               └─-.slice @150ms   There seems to be a problem with the network manager service.  The top of the systemd-analyze blame log looks like this:       24.209s NetworkManager-wait-online.service      10.056s systemd-udev-settle.service       1.499s plymouth-quit-wait.service        936ms media-TStore1.mount        487ms dev-disk-by\x2duuid-920a92b0\x2d6e65\x2d4a7a\x2d855d\x2d81cb436cd85f.device        425ms systemd-rfkill@rfkill2.service        421ms systemd-rfkill@rfkill0.service        407ms media-TStore2.mount        267ms gpu-manager.service        215ms plymouth-read-write.service        209ms systemd-rfkill@rfkill1.service        132ms NetworkManager.service         83ms ModemManager.service   The complete version can be seen .  Also the systemd-analyze plot output can be seen .  Thanks for your time.


In pics: India celebrates Rakhi with fervour  Or In pics: India celebrate Rakhi with fervour  which is correct?

English is not my first language. Sometimes I read some mistakes in newspapers and get confused. Please check below sentences and let me know your valuable feedback.    As per newspapers:     India have won the match.   As per me, it should be:     India has won the match.   My point is that with India (a country) we should use has, right?


My mother-in-law put chicken on the counter to thaw for an hour then put the chicken directly into the sunlight still on the counter top! I've done a little Research but have found nothing that clearly states not to eat chicken thawed in the sun, only how to thaw chicken instead of how not to thaw chicken...any help is much needed I have children and don't want to chance them getting any food Bourne illnesses

I generally defrost meat on the kitchen counter. A friend of mine suggested that this was dangerous and suggested that I defrost meat in the refrigerator. I am no biologist but it seems to me that as long as the meat doesn't get warm defrosting it on the counter should be safe.  Generally, I remove the frozen items from the freezer and place them on a plate on the counter in the packaging they were frozen in. When they are mostly / completely thawed I place the meat in the refrigerator.  Am I wrong and should I be defrosting in the refrigerator?


With the complete redesign featuring the new streaming mixin (which I don't use), it seems that when listening to music from my library (stored on my device) I can only shuffle songs within a single album for an artist.   This is not a dupe of , in that I'm not asking how to shuffle all songs in the library.

In the old version of the music app you could shuffle all songs when songs were selected:      This feature seems to be absent in iOS 8.4 and the new music app:      What are the options for shuffling all my songs in the new version of the music app under iOS 8.4?


Can a Moderator view our personal email and other private information? If they can, then how can Stack Exchange make sure that they will not abuse using it by selling members' info or for any other purposes?  -- added --  I personally think a physical prevention on StackExchange is urgently needed. What if a Moderator lost their account and some unauthorized persion get into their account? Would that be risk of exposing milions of members information on StackExachange?   Yeah,  moderators are selected under a great deal of scrutiny. But mostly is based on their reputation score and their contribution on the forum. But does a student with good result make them a good student in morality? Does a rich guy or a guy with high status in society make them a truly good citizen? Many news shows us otherwise. Simply just having an agreement is not a good way for prevention. Most moderators are expert in computer. So, if they really plan to do something bad, they will certainly plan carefully that it would not be easy to trace them and bring solid evidence. Even if does, they maybe on the other side of the world, it would take months or years to sue them. Even so, all members private info are already expose in the beginning.  My suggestion is that members private information shouldn't go outside of StackExchange. Moderators can only view members ID. If they have anything need to contact members directly, they can do it using StackExchange tools. I believe this way is the much better way of protection on members' information & privacy.

When editing my user profile (name, date of birth, etc.), how can I tell which information can be seen by other users (publicly visible) and what is only used by the system (and how it's used)?


I have a list of unknown length which I want to get the 5th to last, 4th to last, and 3rd to last elements from:  So if my list is like. a = [0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10]  I want to get. b = [6, 7, 8]  I can get this with b = a[6:9]  But the issue is my list could contain any number of items, so it could be.  a = [0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13]   and in this case b should be [9, 10, 11] which b = a[6:9] does not give.  How can I always get the 5th to last third last items in a list, my list will always be over 5 elements long.

I need a good explanation (references are a plus) on Python's slice notation.   To me, this notation needs a bit of picking up.   It looks extremely powerful, but I haven't quite got my head around it.


Question:      Let $f:\mathbb{R} \rightarrow \mathbb{R}$ be continuous and $|f(x) - f(y)| > |x-y|$ for all $x,y \in \mathbb{R}$ and $x \neq y$. Prove that the range of $f$ is $\mathbb{R}$   Answer: I have a hard time writing this.  For any [$x_0, x_1$], it must be that the function within this interval is strictly increasing or decreasing. Otherwise, there is a max (or min) value $f(x_2)$ such that $x_2 \in (x_0,x_1)$. Applying the Intermediate Value Theorem on $[x_0,x_2]$ and $[x_2,x_1]$, then there exists a point $a \in [x_0,x_2]$ and $b \in [x_2,x_1]$ such that $f(a)=f(b)$, contradicting $|f(x) - f(y)| > |x-y|$ for all $x,y \in \mathbb{R}$.  Furthermore, for arbitrary $y_0, y_1, y_2$, if $|f(y_2)-f(y_1)| > |y_2-y_1|$ and $|f(y_1)-f(y_0)| > |y_1-y_0|$ then we have $|f(y_2)-f(y_0)| > |y_2-y_0|$. Otherwise it means that the function on $[y_0,y_1]$ and $[y_1,y_2]$ were not both strictly increasing or strictly decreasing, which leads to the same contradiction, that there exist a $c \in [y_0,y_1]$,$d\in [y_1,y_2]$ on each interval respectively where $f(c)=f(d)$.  Would I be able to then conclude that the range is $\mathbb{R}$? Logically it seems like I can, but it also doesn't seem to be based on any "theorem". I'm essentially just saying "dot dot dot and so on". I don't know if I'm missing anything, or if the arguments are not sound.  Is there a more rigorous way to prove this?

Let $f:\mathbb R \to \mathbb R$ be a continuous function such that $|f(x)-f(y)|≥|x-y| ,\forall x,y \in \mathbb R  $ , then how do we prove that $f$ is surjective ?


In short: I do not know where to start reading so that I can understand how to configure a DC.  The long question:  In the environment I work, we use an outdated domain controller and I have to create a new one. The problem is that I can not yet grasp the idea of the Domain Controller. The one we use is actually used just for authenticating users (single domain, no one else in the forest, no other forest).  The theory I (think) know in short is:   An active directory is a database that stores information about computers and users. A domain controller is a server that holds the active directory and maybe other services such as DNS. A windows server can be a domain controller if it has active directory. I can restrict users from using a printer for example. I can change the settings for a given user account (let's say desktop background?)   What I can not grasp is generally the big picture, but specifically:   Why are there users and computers and not just users, what can I do with each of them. If I restrict a user from using a printer, what is it that prevents him from actually using it if he can reach it (by ip for instance). Why would I put different types of users in different containers, instead of just putting them in "Users" and then making them members of different groups that have different rights. Is it just an aesthetic matter, everything being tidy and sorted? The biggest problem: I do not know what else it can do (please give me some example situations where it could help)   What I guess I expected was that there would be more to this wonder, the Domain Controller, than just authenticating users.  Any help on any of the above matters would be greatly appreciated. Thanks in advance!

This is a  about Active Directory Domain Services (AD DS).         I find myself explaining some of what I assume is common knowledge about it almost daily. This question will, hopefully, serve as a canonical question and answer for most basic Active Directory questions. If you feel that you can improve the answer to this question, please edit away.


I'd like to set a single directory inside Dropbox in which files are encrypted on a file-by-file basis.  At the moment, I use a 2Mb Truecrypt container inside my Dropbox which I then have to mount manually, access/change the files within, then unmount manually.  At that point, the entire 2Mb uploads to Dropbox.  This is a pain for a number of reasons :   Dropbox sync will only occur when the Truecrypt container is unmounted, because Dropbox only syncs files that aren't locked and mounting a container locks it. A single byte change to one file inside that container results in the whole 2Mb being uploaded again. It doesn't scale - I was originally using a 10Mb container, but obviously the bigger the container, the longer it takes to sync when it's unmounted.   I was wondering if I can somehow use LUKS to implement file-by-file encryption to get round the "container" issues.

I'd love to use Ubuntu One or Dropbox features, like file storage and so on, but I don't want anyone else to access my data, USA Patriot act etc.. I want things to be encrypted so that the only place where info is decrypted is only my devices. Is that possible with Ubuntu One or Dropbox?


I'm using SmtpClient to send email. But when I use it with Port 465 it fails. It works with the following ports: 587 & 25. I read that ports 25 and 587 are for TLS, while port 465 for SSL.  Im using enableSSL as true, and I'm sending from gmail to gmail account.

Instead of relying on my host to send an email, I was thinking of sending the email messages using my Gmail account. The emails are personalized emails to the bands I play on my show.   Is it possible to do it?


Let us assume that we have a graph created by a program different from LaTeX (that is not with PStricks or Tikz). I was wandering if it is possible to incorporate mathematical symbols on that graph using a TeX editor.  Thank you.

Recently I have learned how to draw simple stuff with TikZ. I really like it. Now I wonder if it is possible to draw with TikZ on a image. Instead of pasting a image in Illustrator and adding some vectors to point something in the picture I would like to do it using TikZ. Is it possible?   For example, on a picture of a computer (PNG,etc) I would like to draw some arrows and labels saying "Keyboard", "Monitor", etc.


Why the coverage code is 0?  global with sharing class OutputControllerMap {      @RemoteAction     global static List<Output__c> findAll() {         return [SELECT Id, Name, Project_Type__c,Beneficiary_Full_Name__c, Commune_del__c,  Departement_del__c,     Locality__c, GPS__Latitude__s, GPS__Longitude__s                     FROM Output__c];     }  }   Test class  @isTest public class OutputControllerMapTest {   static testMethod void OutputControllerMapTest()    {     Project__c p = new Project__c();    p.Departement__c = 'OUEST';    p.Project_Name__c = 'Test Mappp';    p.Type_Of_Request__c = 'Collective';    p.Department_FFP__c = 'Agriculture';     insert p;    Milestone_s_Type__c mt = new Milestone_s_Type__c();    mt.Name = 'House';     insert mt;     Milestone__c m = new Milestone__c();    m.Project__c=p.id;    m.MilestoneCategory__c= 'Other';    m.Milestone_s_Type__c = mt.Id;    m.Target_number__c =20;     insert m;    Output__c o = new Output__c();    o.Milestone__c = m.id;     o.Project_Type__c='House';     o.Description__c='hjgjgkjgjhg';     o.Locality__c = 'jklhjlhkjlhjlhkl';  o.Project_Type__c ='House';  o.Departement_del__c ='Ouest';  o.Locality__c ='Leogane';  o.Commune_del__c ='Leogane';  o.GPS__Latitude__s =12.7545;  o.GPS__Longitude__s =-72.54;   Insert o;      Test.setCurrentPageReference(new PageReference('OutputControllerMap'));       OutputController oc = new OutputController();    }  }

This is a canonical question and answer developed by the community to help address common questions. If you've been directed here, or your question has been closed as a duplicate, please look through the resources here and use them to shape more specific questions. To browse all canonical questions and answers, including more unit test resources, navigate to the  tag.  This canonical question is intended to address several classes of common questions by providing a quick summary and links to comprehensive resources:   How is code coverage obtained and calculated? How do I increase my coverage?  Why can't I cover these lines? Why isn't the body of my loop or conditional statement covered?


Could you help me install curl.h library?

Simple enough question: is there some shell command (or GUI method) I can use that, given the path to a file on my system, tells me what package put it there? Assuming the file did in fact come from a package, that is.  Bonus question: what if it's a file that isn't installed on my system? Is there, say, a website that will let me look up a file and see what packages, if any, provide it?


I'm getting an error even though I don't see the problem by reviewing the code.   It says the error is at "char[] linechars;".   I'm not sure why I'm getting this error when using character arrays in the Employee1 class.    public class Employee1 {     public String name;     public String number;      Scanner keyboard = new Scanner(System.in);      char[] lineChars;      public Employee1() {         this.lineChars = number.toCharArray();     }      public void setName() {         System.out.println("enter name");         name = keyboard.nextLine();     }      public String getName() {         System.out.println("your name is " + name);         return name;     }      public void setNumber() {         System.out.println("enter number");         for (int i = 0; i < lineChars.length; i++) {             if (i == 0 || i == 1 || 1 == 2 || i > 0 && i <= 9) {                 number = keyboard.nextLine();             } else {                 System.out.println("must be 1-9");             }         }     }      public String getNumber() {         System.out.println("your number: ");         return number;     } }

What are Null Pointer Exceptions (java.lang.NullPointerException) and what causes them?  What methods/tools can be used to determine the cause so that you stop the exception from causing the program to terminate prematurely?


Say I want to search for an error message like The given filter instance must implement one or more of the following filter interfaces but in the context of MiniProfiler. Is it possible to give more weight to the MiniProfiler part.  In example by enclosing it with asterisks: The given filter instance must implement one or more of the following filter interfaces *MiniProfiler*  Just a theoretical question that popped up in my mind. I think I can find the answer with the current search query too :)

Sometimes I may prefer results that have a certain term:     resize image bookmarklet +chrome   In this example, I want a bookmarklet to resize images. Preferably, I want one that works in chrome, however the term "chrome" isn't required... it's just "nice to have."  Other times I want to exclude a word:     Apple contact sync -iPhone   Here I'm looking for a way to sync contacts but not to the iPhone.  The problem with this query is that it will exclude all pages that have the word "iPhone" anywhere. Now, imagine a blog or site has the exact information I want, but it's excluded from the results since it has a "links" side bar which has the word "iPhone" in it. Basically I want the main content of the page to not include the word "iPhone", or even if it does, to not be the main focus of the content.  Update:  Here's an example you can try it out on:   If you use the search query , you will get the result . Now if you add  to the query, the result will no longer appear. You will notice that the linked page has the word "iPhone" mentioned only once on the page and its not even in the main article's text (it's on the bottom in the Popular topics section).   (I'll try to find better examples... if you can think of any please let me know.)


If we consider a particle such as an electron to have wave-like properties too, what kind of wave it is? What is exactly meant by its wavelength?

Until what point can the  be thought as a real wave?  I mean, is it made of something? What amplitude does it have? Is it a sine wave?   How can it be related to the wavefunction of the particle?


So we have normal scores aka rankings on the x-axis, called theoretical quantiles and on the y we have the sample quantiles, but how do we calculate them, if we assume that the data derives from a normal distribution?  If the result of plot will more or less look like a linear line, then our sample derives from the normal distributed population, right?

Does anyone know what the Inverse Cumulative Distribution Function of Normal Distribution is? Does it have a closed form expression? I did not find any good answer using Google.


I have submitted my question, as I have been unable to request further information from the responders to it, as the system advised that there were 705 too many characters.  Apologies for this, but grateful for a further response.  I thought it would be helpful if I provided the YouTube link to Professor Brian Greene's talk about the nature of space, so as to enable responders the opportunity to view it if they wish.  My comments and observations follow.  The link to Prof Greene's 'space', discussion is: .  During the explanation, Greene posed the question: 'What is space?' to which responses were provided by astrophysicist prof Alex Filippenko: '... we still don't really know what space is'.  Similarly, theoretic physicist, Prof James Gates says: 'it is one of the deepest mysteries in physics.'  So, I still have a comprehension deficit: what is space?  I have great difficulty in rationalising what is it the is being twisted, curved and rippled. These adjectives are used to describe the properties of space, but little attempt is made to describe the nature of what  is undergoing these transformations, i.e. what is space ‘made’ of.  Now, it appears to me that if one valiantly attempts to convey to the layman the properties of something, then it would help to describe what that thing it is ‘made’ of.  The problems in doing so have been acknowledged by august contributors to Prof Greene's programme.  Nevertheless, and despite sometimes, discussing ‘space’ without mentioning the inextricably linked component of time, Prof Greene attempts to explain the nature of 'space'.  I would be grateful for a further response to elucidate the problem I still have regarding what 'space' is comprised of.

General Relativity posits that matter curves spacetime, such that geodesics point towards the object in question, hence, gravity. Now, how does matter do this? What is spacetime "made of", anyway, such that it should interact with matter, being bent by it and forcing it to accelerate (via gravity)?


my question is basic and elementary. I can't seem to understand why the formula for the energy of a particle is $E= -pU$ where $p$ is the 4-momentum of the particle and $U$ is the 4-velocity of the observer. Actually what bothers me also is that when we say an observer has, say, a 4-velocity $U$, we mean it has this velocity w.r.t us (i.e. the person who's doing the calculation) right? the same thing for the 4-momentum of the particle! In other words, for the formula of the energy above why shouldn't it be proportional to the velocity as measured by the observer (not to those making the calculation as we do)?

Gravitation by Charles W. Misner, Kip Throne and John Wheeler page 65 Exercise 2.5.  The book defined "energy" for a photon $E=-\mathbf p\cdot \mathbf u$ for subsection 2.8, which later explained as a "coordinate-free contacts". This was still understandable.(Notice that $c=1$ as usual, and both $p$ and $u$ here represent 4 momentum. )   However, in Exercise 2.5, the book used $E=-\mathbf p\cdot \mathbf u$ again for a particle of non-zero rest mass, where $\mathbf p$ was the particle's momentum with rest mass $m$, and $\mathbf u$ was the observer's 4 velocity.  Further, the book claimed that $|\vec{p}|=[(-\mathbf p\cdot \mathbf u)^2+(-\mathbf p\cdot \mathbf p)]^{1/2}$ was the momentum measured by the observer, with $|\vec{v}|=\frac{|\vec{p}|}{E}$ the ordinary velocity measured by the obsever.  Question:   What does $E=-p\cdot u$ stand for in this context? (for massive particle) Is it really energy? Further, how was $E$ relate to $\vec{p}$ and $\vec{v}$? Especially, how was $\vec{p}$ and $\vec{v}$ calculated?


Code for how to  prevent user from refreshing the page either by using refresh button of browser or CTRL+F5 in angular js

I need to warn users about unsaved changes before they leave a page (a pretty common problem). window.onbeforeunload = handler  This works but it raises a default dialog with an irritating standard message that wraps my own text. I need to either completely replace the standard message, so my text is clear, or (even better) replace the entire dialog with a modal dialog using jQuery. So far I have failed and I haven't found anyone else who seems to have an answer. Is it even possible? Javascript in my page: <script type="text/javascript">        window.onbeforeunload = closeIt; </script>  The closeIt() function: function closeIt() {   if (changes == "true" || files == "true")   {       return "Here you can append a custom message to the default dialog.";   } }  Using jQuery and jqModal I have tried this kind of thing (using a custom confirm dialog): $(window).beforeunload(function () {     confirm('new message: ' + this.href + ' !', this.href);     return false; });  which also doesn't work - I cannot seem to bind to the beforeunload event.


I'd like to know how would it be possible to approximate the size of a set that has no duplicate elements.  We can make a limited amount of requests. Each request gives us a random element from the set (Without removing it).  How do we approximate the size of the set given the amount of duplicate elements gotten from the set when doing $x$ requests?

Here is the problem I'm trying to solve:  In order to send spam, a spammer generates fake nicknames, by picking random girl names (and appending a random number to it). I suppose it randomly and fairly picks names from a fixed list, and I get to observe the outcome. Over time, names eventually start repeating.  From the distribution of the repetition count of every distinct name, is there a way to estimate the size of the fixed list ?  Intuitively, if there was no repetition among the names I have observed, I would have no information about the size of the list, but the minimum bound given by the actual distinct names observed.  On the other hand, if the distribution of the repeat counts is far away from zero, I can be reasonably confident that the sample size is much larger than the word list, and that I probably have observed the full list already.  The problem lies in the middle zone. So far the distribution of repeat counts looks like this:  $$ \begin{matrix}       n & k \\    114 & 1  \\     66 & 2 \\     30 & 3 \\      4 & 4 \\      2 & 5 \\      1 & 6 \end{matrix} $$  Here $n$ is the count of distinct names appearing $k$ times in the sample.  Is there a simple estimator for the size of the list?


Which is correct:  The Faculty of History at Jagiellonian University  or  The Faculty of History of Jagiellonian University  ?

I am reviewing an edited document in which the editor changed      Prof Doe in the Department of ... in the Faculty of ... at the University of ...       to      Prof Doe at the Department of ... at the Faculty of ... at the University of ...   I'm pretty sure I'm right, but I don't want to make arbitrary corrections.  [Use of capitals for names of departments and faculties, and dropping the full stop from Prof not at issue — these are all house style]


Suppose I have 4 lists.  group = [1] question_number = [1,2,20,22,34,36] response = range(1,6) score = range(100,-1,-25)   I'd like to get all tuples of selecting one element from each list.    (1,1,1,100) (1,1,1,75) ... (1,36,5,0)   I could do this with  loop, but I am wondering if itertools has something easier?  I know itertools.combinations can get all combos of length n.  Is there a similar function for multiple lists?

How can I get the Cartesian product (every possible combination of values) from a group of lists?  Input:   somelists = [    [1, 2, 3],    ['a', 'b'],    [4, 5] ]   Desired output:  [(1, 'a', 4), (1, 'a', 5), (1, 'b', 4), (1, 'b', 5), (2, 'a', 4), (2, 'a', 5) ...]


I have often written sentences in the following form which combines a statement with a question, separated by a semicolon. For example,      I understand you have received payment for my order; will it ship by Monday?   Is this use of the semicolon correct, and is the semicolon commonly used in questions?

How does one correctly use a semicolon?  It is probably one of the more difficult punctuation marks to master in my opinion.


What is meant by packages and repository in Ubuntu?  I see a new thing in Ubuntu that it is required to update packages for installing any software.  So question is that what are these two terms?

I recently posted an answer where I wrote add the PPA. But I now realize, that I have no idea what the difference between a PPA and a Repository is. So can someone please explain it to me?


I want to include a .png file that is called Screenshot 1 and is in folder Screenshotsforassignment, but typing \includegraphics{Screenshot 1} gives me the error:   LaTex Error: File 'Screenshot 1' not found.   Does anybody know how to fix this?  Edit: I solved it!

I want to import graphics into my main input file using the macro \includegraphics. It does not work if the filename contains spaces.   also discusses this subject, but there is no solution there.  My compilation routine is latex->dvips->ps2pdf (because of PSTricks).


How to install Ubuntu on Nokia C5-00 mobile? Provide a step by step process of installation on Nokia system symbian mobile.

With the announcement of the Ubuntu Phone OS I'd like to know what phone (and tablet) models are supported at this time.  Note from foss & Oli: We are making this the master question for all future "Will this work on <insert random tablet/phone/device here>?!" questions


I am building a loop to fetch all the rows from my database and output them into rows for a table.  I am adding a select all checkbox at the header of the table when checked, it selects all, when unchecked, it deselects all.  I cant get it to work for some reason if someone can show me support.

<input type="checkbox" id="selectall">Select all</input>

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          <?php $request = mysql_query('SELECT * FROM users');  while ($table = mysql_fetch_array($request)) {     echo '
';     echo '
<input type="checkbox" class="selectedId" name="selectedId" value="' . $table['id'] . '" onclick="resetSelectAll();" />
';     echo '
' . $table['id'] . '
';     echo '

';     echo '
' . $table['username'] . '
';     echo '
' . $table['email'] . '
';     echo '
' . $table['active'] . '
';     echo '
' . $table['user_level'] . '
';     echo '

';     echo '
';  }         ?>
   my javascript:      does anyone notice a problem?  here is a js fiddle

I'd like to do something like this to tick a checkbox using jQuery:  $(".myCheckBox").checked(true);   or  $(".myCheckBox").selected(true);   Does such a thing exist?


I try to find and stock in HTML paragraphe all the word.  Actually, I have a function like this  p.html(function(index, oldHtml) { return oldHtml.replace(/\b(\w+?)\b/g, '<span>$1</span>'); });   But it's only return word without accent. I test on regex101.com   Any idea ?

How can I use Unicode-aware regular expressions in JavaScript?  For example, there should be something akin to \w that can match any code-point in Letters or Marks category (not just the ASCII ones), and hopefully have filters like [[P*]] for punctuation, etc.


I want to load image in blender using the python API such that it appears in the background whenever I render a 3D model.

Fairly new to python and blender, so apologies if this is super basic. I've searched around and haven't found an answer.  I'd like to render some procedurally generated objects with a background image. In case it makes a difference, I'm using:    I don't need any interaction between the generated object and the background image so I've left a skeleton script I'm using to render below  import os DIR ="/home/path/to/folder" bg_file = os.path.join(DIR, "myimage.jpg") bg_img = bpy.data.images.load(bg_file) bpy.data.scenes['Scene'].render.filepath = os.path.join(DIR, "image") bpy.context.scene.camera = bpy.data.objects['Camera'] bpy.ops.render.render(write_still=True)   I managed to find some scripts that seem to be trying to do what I want online, but none that I could get to work. e.g.  import bpy filepath = "/home/path/to/folder" img = bpy.data.images.load(filepath)  for area in bpy.context.screen.areas:     if area.type == 'VIEW_3D':         space_data = area.spaces.active         bg = space_data.background_images.new()         bg.image = img         break  cam = bpy.data.cameras.new("Camera") cam_ob = bpy.data.objects.new("Camera", cam) bpy.context.scene.camera = cam_ob bpy.context.scene.objects.link(cam_ob) bpy.context.scene.objects.active = bpy.context.scene.objects["Camera"]   Any thoughts/tips would be greatly appreciated!


For any point outside of a circle, is there ever only one tangent to the circle that passes through the point?  Are there ever more than two such tangents? (I cannot find the exact answer i need through the other question answered. My question does not involve any actual numbers and equations. It's hard for me to find the answer within that question. ) Thank you!

Find the combined equation of two tangents drawn from $P(x_1,y_1)$ to the circle $x^2+y^2 = a^2$. Point $P$ lies outside the circle.


I am rendering an animation in Blender that should take about two days. I am using the CPU to render it because Blender does not support my GPU. After one day non-stop of rendering I have noticed that my iMac (2013 edition, intel core i5 CPU) was getting hot (about 85 degrees) and I do not want it to get harmed. Unfortunately I have chosen to render the whole animation to a video sequence directly and not to a set of images, so I cannot allow myself to stop the whole process. So is there any way to pause or reduce Blender's activity so that my computer can cool itself before restarting?  I have already tried the commands renice and killall -s STOP but with no result.

Apparently my CPU or GPU overheats when Blender renders more than a few minutes.  The computer suddenly powers down, taking down all running apps, email I'm writing, etc.  This is almost never a problem with still scenes, which finish soon enough, but often with animation renders.    The problem occurs with either Cycles or BI renders.  I'm running on a custom-built quad core 64-bit linux desktop system.  (I'm not the one who built it. I am  a knuckle-dragging caveman with hardware issues.) (Yes, all the fans are blowing and dust has been cleaned off.)  So far the only way to prevent this for now is to choose in camera properties: Performance, Threads, Fixed, 1.     Someday, I'll get better hardware, but in the meantime, I suspect Blender could run indefinitely, even with multiple threads, if I could make it pause for perhaps one minute between each frame when animating, just to cool down. How to make this happen?  At least, a way to run an arbitrary Python script between frames, or once per minute during any rendering. Such a script could contain a sleep stat  Even better, if Blender could throttle its rendering effort based on readings of the CPU temperature sensor.   Is that possible?  UPDATE: I've nearly forgotten about this issue, since writing a quick Python script to watch the CPU temperature, sending SIGSTOP and SIGCONT as gandalf3 describes. Zero crashes ever since. I reboot my machine once or twice per year for kernel upgrades, otherwise it's 100% up.  ANOTHER UPDATE: I took the machine apart, popped off the CPU heatsink, and applied fresh thermal paste.  Ever since, the CPU temperature has been running something like 30deg (C) cooler all the time.  Zero shutdowns, and I don't use the Python script any more unless I'm feeling paranoid.


There is a spell that can summon familiars, and a beastmaster ranger gets a companion, but is it possible to get an animal companion that is not a familiar without being a ranger or multiclass ranger? Without the animal being a horse, and it being able to attack?  I'm playing either a L4 Drow (Champion) Fighter or a L1 Tiefling (Draconic Bloodline) Sorcerer.

I'm fairly new to DMing and so is my group, so we are all on a learning curve together. We're playing D&D 5e.  Last week a fighter in our group tamed a wolf with Animal Handling and then requested that he keep the wolf. I allowed this, but now I'm not sure about how to play the wolf.  Specifically, how can he train the wolf to perform certain actions such as attacking?  What other things might I need to be aware of with a PC owning a "pet"?


Given two lists, the objective is to find the non-overlapping value between them. Based on the suggestion discussed in . This can be achieved either of the two approach list_one=['ISL','BUK','ORG','CLC','STS','PLP','t1','t2','t3','t4','DE1','DE2','DE4'] list_two=['t1','t2','t3','t4']  APP1=set(list_one) ^ set(list_two)  APP2 = set(list_one).symmetric_difference(list_two)  Both suggestion outputted {'DE4', 'DE2', 'CLC', 'STS', 'ORG', 'BUK', 'ISL', 'DE1', 'PLP'}  While this work, but the order from list_one is distorted. My question is, how can the above code be modified to output as below, where, the ordering follow as per in list_one EXPECTED_OUTPUT=['ISL','BUK','ORG','CLC','STS','PLP','DE1','DE2','DE4']

Is there a built-in that removes duplicates from list in Python, whilst preserving order? I know that I can use a set to remove duplicates, but that destroys the original order. I also know that I can roll my own like this:  def uniq(input):   output = []   for x in input:     if x not in output:       output.append(x)   return output   (Thanks to  for that .)  But I'd like to avail myself of a built-in or a more Pythonic idiom if possible.  Related question:


I am aware that if one has random variables, and sums them, then the result belongs to a distribution which is the convolution of the parent probability distributions of the initial random variables.   For example, let $X$ and $Y$ be random variables drawn from the probability distributions $F(t)$ and $G(t)$ respectively. If $Z = X + Y$, then $Z$ belongs to the probability distribution $$Z\sim (F*G)(t) = \int_{-\infty}^{+\infty} F(\tau)G(t - \tau) \ d\tau \text{.}$$  Does this principle or theorem have a name? Is it part of central limit theorem? I want to be able to refer to it quickly rather than explain the above every time.

For long time I did not understand why the "sum" of two random variables is , whereas a mixture density function sum of $f(x)$ and $g(x)$ is $p\,f(x)+(1-p)g(x)$; the arithmetic sum and not their convolution. The exact phrase "the sum of two random variables" appears in google 146,000 times, and is elliptical as follows. If one considers an RV to yield a single value, then that single value can be added to another RV single value, which has nothing to do with convolution, at least not directly, all that is is a sum of two numbers. An RV outcome in statistics is however a collection of values and thus a more exact phrase would be something like "the set of coordinated sums of pairs of associated individual values from two RV's is their discrete convolution"...and can be approximated by the convolution of the density functions corresponding to those RV's. Even simpler language: 2 RV's of $n$-samples are in effect two n-dimensional vectors that add as their vector sum.           Please show the details of how the sum of two random variables are a convolution and a sum.


Been trying to solve this problem for a couple of days now: Let $E \subset \mathbb{R}$. Prove that if there exists $0 \leq \delta < 1$ such that for every interval $[a,b]$ we have $$|E\cap[a,b]|_e \leq \delta(b-a),$$ then $|E|_e = 0$. Here $|-|_e$ is the exterior Lebesgue measure.

This question is exercise 4.10 of Richard F. Bass's Real Analysis for Graduate Students, 2nd edition.  Let $\epsilon \in (0,1)$, let $m$ be Lebesgue measure, and suppose $A$ is Borel Measurable subset of $\mathbb R$. Prove that if $$ m(A\cap I)\leq (1-\epsilon)m(I)$$  for every interval $I$, then $m(A)=0$.  Collection of my thoughts  1. Try to prove by contradiction, suppose $m(A)=a>0$ Borel Measurable Set satisfies the condition given. A property of any Borel Measurable Set on $\mathbb R$ is $A$ contains a closed set $F$ and is contained in open set $O$, and the measure of $F$ and $O$ can be arbitrarily close to $a$. 2. Obviously $A$ contains no interval, but it does not lead to contradiction, because we can find an example of $m(A)>0$ that contains no interval(fat Cantor Set(remove middle 1/4 each time) has measure $1/2$ and contains no interval).  2'. For fat Cantor Set $C$ and given $\epsilon>0$ how could we construct an interval I satisfies $m(C \cap I)>(1-\epsilon)m(I) ?$   Maybe try to write Borel measurable set as countable union/intersection of intervals.   I'm stucked here and will appreciate any help, some examples/special case will be great too.


This question always throws me:      Discuss if the EPR paradox violates special relativity?   The information of the state of one particle is instantaneously transmitted to the other particle, but does this count? Since this information is not usable and does not allow you to transmit a message - it is equivalent to just getting a random set of characters.  Edit  The answers to the  states that basically what I have stated in my question. I am, however, more concerned whether it is counted as a violation of special relativity, I am aware that instantaneous communication does occur.

recently i was watching a  on quantum computing where the narrators describes that quantum entanglement information travels faster than light!  Is it really possible for anything to move faster than light? Or are the narrators just wrong?  Regards,


I am using the sql query like  SELECT fun_systemuser(UserID) as ConsultantName,        fun_store(UserID) as StoreName,        count(UserID) as No_of_PhoneModel,        PhoneModelID,        (select LeegraRegion            from store           where ID=claim.StoreID) as Region,        fun_network(UserID) as ChannelName,        fun_group(claim.StoreID) as GroupName,        fun_campaigns(UserID) as CampaignName     FROM `claim`   where UserID IN (SELECT id                      FROM `systemuser`                     WHERE `RoleID`=1                       and `Topconsultant`=1)     and StatusID=5   group by UserID ,PhoneModelID   I have query result like given below:    There are 4 records for single consultant with different phone model id and no. of sales of phone model id.  I want to single record for every consultant name and there should be show phone model and no.of phone model with comma separated value.  Ex. single record should display like below  Thomson 4U-Sunnypark 3,2,3,1  1,3,6,9 Pretoria Vodacom Sachar Mobile vodacom Campaigns   Is anybody know what should I use in query so I can get the result as I want. Thanks in advance.

Using MySQL, I can do something like:  SELECT hobbies FROM peoples_hobbies WHERE person_id = 5;   My Output:  shopping fishing coding   but instead I just want 1 row, 1 col:  Expected Output:  shopping, fishing, coding   The reason is that I'm selecting multiple values from multiple tables, and after all the joins I've got a lot more rows than I'd like.  I've looked for a function on  and it doesn't look like the CONCAT or CONCAT_WS functions accept result sets.  So does anyone here know how to do this?


There are many swords made of Valyrian steel. Can anybody throw light on how many are there in total in the known world?

As of 298 AL, where A Game of Thrones  begins, where were the various Valyrian steel weapons that exist?  That is to say, before the 1st chapter starts. The swords are already in someone's hands at the beginning. I just want how many and who owns them. I don't want to know how they pass to new owners as the story progresses.


I am writing my thesis and i have draw a hypothetical curve. Later I have to relate this with simulated data. The picture has a quadratic equation and some sample points are drawn. Now i have to draw a bell curve on each data points to show that their mean lies on the curve or they stay within the deviation. How do I draw that? Is it even possible to draw something like this. I am sorry, i already left the lab and couldn't bring the code related to the picture. Any help or guidance is really appreciated. Please also let me know if the question is not clear. I am also stumbling on making my expectation clear. Thanks in advance.    Hope this sheds some light.

I want the make the following population regression function with pgfplot.     My attempted code is  \documentclass[border=5mm]{standalone} \usepackage{pgfplots}   \begin{document}  \begin{tikzpicture}[ % Define Normal Probability Function declare function={             normal(\m,\s)=1/(2*\s*sqrt(pi))*exp(-(x-\m)^2/(2*\s^2));         }        ] \begin{axis}[     no markers   , domain=-3.2:3.2   , samples=100   , ymin=0   , axis lines*=left   , xlabel=     , every axis y label/.style={at=(current axis.above origin),anchor=south}   , every axis x label/.style={at=(current axis.right of origin),anchor=west}   , height=5cm   , width=12cm   , xtick=\empty   , ytick=\empty   , enlargelimits=false   , clip=false   , axis on top   , grid = major   , hide x axis   , hide y axis   ]    \addplot[cyan!50!black, rotate=-45] (x, {normal(0, 1)});  \end{axis}   \end{tikzpicture}  \end{document}     Any help to get this graph will be highly appreciated. Thanks


In my website, there's a user's profile page. What I have currently doing is just pass the user ID via a GET request and use it to query the user's details.   So, the user profile URL is like this...  http://www.example.com/user.php?id=345   So, my problem is that, is it safe to show this user's ID (Primary key of the user table) in the URL so, that anyone can see it... ?

I've heard that exposing database IDs (in URLs, for example) is a security risk, but I'm having trouble understanding why.  Any opinions or links on why it's a risk, or why it isn't?  EDIT: of course the access is scoped, e.g. if you can't see resource foo?id=123 you'll get an error page. Otherwise the URL itself should be secret.  EDIT: if the URL is secret, it will probably contain a generated token that has a limited lifetime, e.g. valid for 1 hour and can only be used once.  EDIT (months later): my current preferred practice for this is to use UUIDS for IDs and expose them. If I'm using sequential numbers (usually for performance on some DBs) as IDs I like generating a UUID token for each entry as an alternate key, and expose that.


Can I use a phone USB-C charger (e.g. the ) to charge my 2016 MacBook Pro? How about a USB-A charger with a USB A->C cable?  Physically it fits, but  says that it is not a good idea, without elaborating why.

We've got a range of laptops in our office all macbook pros some of which are 13" and some of which are 15".  The 15" laptops came with 85w chargers, and the 13" came with 60w chargers.   I want to buy some additiaonl chargers to leave plugged in around the office for anyone to use, but im unsure as to which type i should get.    Would charging a 13" laptop on a 85w power supply damage it ?  Would charging a 13" laptop on a 60w power supply damage it, or just make it slow at charging ?


I'm not sure what went wrong, I have particles that I set as objects and they show up in render image but not render animation. I'm using cycles as the render engine. The actual objects do show up its just that the particles set as objects (more specifically a collection) does not show up. Any help would be greatly appreciated.

This is meant to solve this problem once and for all. What is every reason an object isn't showing up in a render or viewport in when using the cycles render engine?


I have spent days to finish a simple python script, it layout like following:  import sys  several functions  infile = sys.argv[1]  # input file inconfig = sys.argv[2]  # input file outfile = infile.split(".")[0] + "_new.fxs" # output file  inputfile = open(infile, "r") inputconfig = open(inconfig, "r") outputfile = open(outfile, "w")  tmp_dict = getdict(inputconfig) # using a function named getdict  tmp_buffer = transblock(inputfile, tmp_dict.keys()) # using a function named transblock outputfile.write(tmp_buffer)  inputfile.close() inputconfig.close() outputfile.close()   By now, I use   python script.py inputfile inputconfig   in command window to run it. Yes, it works as expected.  I would like to learn more, could anyone show me how to use the symbol  __name__ == "__main__":   to coding this out as a expert? I means something like this:  import sys  several functions  if __name__ == "__main__":     statements     ...

Given the following code, what does the if __name__ == "__main__": do?  # Threading example import time, thread  def myfunction(string, sleeptime, lock, *args):     while True:         lock.acquire()         time.sleep(sleeptime)         lock.release()         time.sleep(sleeptime)  if __name__ == "__main__":     lock = thread.allocate_lock()     thread.start_new_thread(myfunction, ("Thread #: 1", 2, lock))     thread.start_new_thread(myfunction, ("Thread #: 2", 2, lock))


I'm facing a very annoying problem that I noticed a week from now and for which I can't find an answer: my network suddenly stops responding, usually coming back exactly 25 seconds later. I was using kernel 3.10.4 and now migrated to 3.11-rc4 to see if something changed, but no, the behavior is the same. And since it is a hard to spot problem due to the fact usual web surfing is in "bursts" and the outage is completely random, I can't really tell this problem was present in a previous kernel as well (I always use custom but unpatched kernels from kernel.org, all compiled by myself)  I can't tell the kernel is the culprit either, but I can say there are no clues on the system logs (I checked both /var/log/syslog and /var/log/messages and there is nothing unusual there) and that hardware doesn't seem at fault, for the problem shows up using either one of my network cards:  lspci output:  02:00.0 Ethernet controller: Broadcom Corporation NetXtreme BCM5751 Gigabit Ethernet PCI Express (rev 01) 04:00.0 Ethernet controller: 3Com Corporation 3c905B 100BaseTX [Cyclone] (rev 30)   and I already tried to exchange the ethernet switch ports and still no one else where I work has a problem except me (although we use similar machines, I'm the only one using Linux, so I had to take some infamous jokes about it as well... hehe).  I ran up wireshark on my machine and left it continuously pinging our gateway and another machine on the same network segment. Then, at the first sign of network malfunction I would check it and verify the gateway stopped responding pings, but the other machine was still there responding normally. Some other times is the other machine which stops responding and the gateway is fine, and some other times both stop responding. I don't know what else to do, so I'd like some help or tips on how to further debug this, since the system logs are completely normal.  I have my kernel config file and a capture file from wireshark showing the situation. I can post here or at some pastebin site in case anyone finds it useful to understand the case, just please let me know the detail level I should use (I guess the packet level without the raw data would be enough).

From time to time Linux and Unix users faced with various network problems. Many of these problems are presented here and at some others troubleshooting forums, but they are very concrete and contains a lot of additional technical information, and sometimes it's rather difficult to understand the main point and the real reason of buggy system behavior.   By asking this question, my intention is to start a community wiki page which allows generalizing our network troubleshooting and debugging experience. I hope the Linux and Unix users could easier recognize and solve("divide and conquer") their network problems using this page.   The parent of this page should be  . But here we should focus on troubleshooting the network problems from user- and kernel-space.  I suppose, if you:    Share the information about using some great network diagnostic tool with concrete usage examples and examples of network bugs, which they help to catch. Share the link to the great network tutorial connected with this subject Tell about a general method or recipe which allows to tackle some class of network problems Share information about your tool-set for network debugging and troubleshooting   it would perfectly fits for this topic.    I'll begin from sharing the link to varios  and . Also  seem to have actual information about our subject. And for diving into linux networking we definetely need to visit .


I understand that a nuclei with too many protons is unstable as the electromagnetic repulsion becomes too strong to be balanced by the strong nuclear force.   However in the case of there being too many neutrons, surely the addition of neutrons should be adding extra strong nuclear force without extra electromagnetic repulsion, which should make a nucleus more stable. Why is this not the case?

If you take any large nucleus and add protons to it, the electrostatic repulsion between them will make the nucleus more unstable, because the electrostatic force between them is more repulsive at a greater distance than the strong force is attractive  So how come if you add more neutrons, which don't have a charge and so there is no electrostatic force, the nucleus still becomes more unstable?  Also why aren't there groups of neutrons bound together, so purely neutron nuclei (because they are neutral, I'm guessing they couldn't form atoms, because of the electrons needed for an atom)


I have a folder with a list of folders.  Without manually going through the list and typing the name of each folder, is there a way I can get a new line delimited list of the folders (or file names for that matter) in that directory?

In windows, is there any way to get a list of all files in a folder, including all the files within all the subfolders?


When I look at my Google Analytics dashboard, I see most referrals from a website called rank-checker.online which highly skews up my data.  There are other such websites, get-rick-quick, free-social buttons etc, because of which I am unable to get an actual overview of the site users. Is there a way to not see the data from these?

Last months I have lots of referrer spammers in my GA statistics. Their count is ~10x higher than count of legit visitors (my site is not very popular yet). I've turned on an option to hide known spammers in GA settings, but it didn't help at all. It seems these spammers are using scripts to spam directly to GA (i.e. they are not logged in my IIS).  Is there anything I can do to stop these spammers?    UPD 10 months later, and they started spamming using fake target page names... and Google is still doing nothing about it.


Let $G$ be an abelian group of  order $n$, and $a_1,a_2,...a_n$ its elements. If $G$ has more than one nontrivial elements with order $2$, how to show that $\prod^n_{x=1}a_x=1$?

Suppose $G=\{a_1,...,a_n\}$ is a finite abelian group, and let $x=a_1a_2\dotsm a_n$.   Prove that if there is more than one element of order $2$ then $x=e$.   What I've done so far: (#1 is just for illustration, There should be at least $3$ such elements)   $G$ has an even number of elements with order $>2$ (They are paired so: $(a,a^{-1})$ ). And then there are $e$ and $\{b|o(b)=2\}$. Also, if $G$ has at least one element of order 2 then $|G|$ is even (Lagrange). Thus $|\{b|o(b)=2\}|$ must be odd. If there is exactly one element $b$ of order $2$ then $x=b$. That's because $G$ is abelian, and we can write: $x=e\cdot b\cdot(a_1 a_{1}^{-1}\dotsm a_n a_{n}^{-1})=b\cdot(e\dotsm e)=b$. If there are exactly $3$ such elements $a,b,c\in G$, then, as shown above, $x=abc$ and thus $x=e$ (That's because $(abc)^2=a^2b^2c^2=e$ which means $abc\in \{a,b,c,e\}$. If $abc=a$ then $b=c^{-1}=c$ which is false, same goes for $abc=b,abc=c$.)   I haven't managed to find a reason why the claim must hold for $5, 7, ...$ (i.e. All other odd integers). Does anyone have an idea?  Thanks in advance. Please excuse my English.  edit: Not a canonical answer but a simple one (if such even exists).


I have a new tablet PC with Windows 10 which doesn't have a physical keyboard. This is OK for most applications, the on-screen keyboard works fine for most uses. However, one of the primary applications for me is to play videos over an external monitor/projector via HDMI, and for that I've found one relevant shortcoming:   The on-screen keyboard doesn't have a Windows key, which I'd need to quickly send a window to the external monitor (Windows+Shift+Right Arrow) and/or put it in full-screen mode (Windows+Up Arrow).   And all the other shortcuts (Windows+I, Windows+X etc.etc.) would be nice to have as well. Is there any way to get them (or an alternate way to simulate them)?

At times it would be very helpful to have up and down arrows while using the Windows 10 tablet onscreen keyboard. Is this possible?


I disabled the password for my user account while I was logged in (I was the only administrator). But I did not enable automatic login. I switched user to "Guest", but when I switched back to my account (the administrator account), my user account askes me for my password. When I type my password in, it says its incorrect. So I need a way of accessing my user account if this is the case.

I'm working on a Ubuntu system, and my client has completely forgotten his administrative password. He doesn't even remember entering one; however it is there.  I've tried the suggestions on the website, and I have been unsuccessful in deleting the password so that I can download applets required for running some files. Is there a solution?


i intend to travel to Osaka, Japan via Shanghai Pudong International Airport on China Eastern Airlines.  Since i only have a 4.5 hours transit at the Shanghai Pudong International Airport, do i need a Transit Visa in this regard? or can i do an Airside/Direct Transit at Shanghai Pudong International Airport without crossing/entering the Border Control?

I'm hoping to get a flight which requires me to be in China for 28 hours before the connecting flight out.  I'm happy to sit in transit if I have to.  However, I've read one site that said 12 hours is the maximum transit permitted.  Can anyone find either:   Definitive information saying how long transit in Beijing/Shanghai airports are for Or can I get a transit visa on arrival, in which case I'll go check out the city for a day ;)   I'm on a New Zealand passport if it makes a difference.  Failing all that I'll pick up a visa in Mongolia en-route, I'd just rather not have to waste a few days doing so if I don't have to!


I would like to create a table, which look like this:    \documentclass[a4paper,12pt,oneside]{article} \usepackage[english]{babel} \usepackage{tikz} \usepackage{pgf} \usetikzlibrary{shapes,arrows,positioning,calc,threeparttable}  \usepackage{tabu} \usepackage{hyperref} \usepackage{longtable} \usepackage{array} \usepackage{multirow,tabularx,booktabs} \begin{document} \begin{tabular}{|c|c|} \hline  \bf{Text A:} & \bf{Text B:} \\  \hline  "Lorem ipsum dolor sit amet, consectetuer adipiscing elit, sed diam nonummy nibh euismod tincidunt ut laoreet dolore magna aliquam erat volutpat." & "Lorem ipsum dolor sit amet, consectetuer adipiscing elit, sed diam nonummy nibh euismod tincidunt ut laoreet dolore magna aliquam erat volutpat." \\  \hline  \end{tabular}  \end{document}   Can someone help me?

I would like to create a table with some columns' width specified, while the text in those columns should be centered both horizontally and vertically. I found out that  \usepackage{array} \begin{tabular}{| c | c | m{5cm} |}   vertically centers the text in the last column, but justifies it horizontally (like text in normal paragraphs).  Update: With Jake's method, it seems both \\ and \hline cause an error. How to fix it?


Let $\emptyset \not = X\subseteq \Bbb{R}^n$ be convex and compact and let $\cal{A}$ be a family of affine maps from $\Bbb{R}^n$ into $\Bbb{R}^n$ such that $X$ is invariant under each element of $\cal A$ and $f\circ g = g\circ f$ for any $f, g \in \cal A$. I am trying to show that elements of $\cal A$ have  a common fixed point which is in $X$.  Any idea or references would be helpful.

Let $\emptyset \not = X\subseteq \Bbb{R}^n$ be convex and compact and let $\cal{A}$ be a commuting family of affine maps from $\Bbb{R}^n$ into $\Bbb{R}^n$ such that $X$ is invariant under each element of $\cal A$. How can I show that $\cal{A}$ has a common fixed point.   Remark I know this is a consequence of some stronger theorems such as Markov-Kakutani fixed point theorem. But I have no access to its proof. Besides I am looking for a much elementary proof (which I think must exists for this special case).


There are certain  a Warlock can get such as Bewitching Whispers which states:  [...] You can cast compulsion once using a warlock spell slot. You can’t do so again until you finish a long rest.  This means that an ordinary Sorcerer/Warlock multiclass could not use spell slots from their Spellcasting feature (Sorcerer spell slots) with Bewitching Whispers. However, the Sorcerer also gets the  feature which states:  [...] You can transform unexpended sorcery points into one spell slot as a bonus action on your turn [...]  I am aware that  to allow features such as Flexible Casting and Metamagic to apply to Warlock spells as they state:  Multiclassing allows you to gain levels in multiple classes. Doing so lets you mix the abilities of those classes to realize a character concept that might not be reflected in one of the standard class options. If you have both the Spellcasting class feature and the Pact Magic class feature from the warlock class, you can use the spell slots you gain from the Pact Magic feature to cast spells you know or have prepared from classes with the Spellcasting class feature, and you can use the spell slots you gain from the Spellcasting class feature to cast warlock spells you know.  However it is unclear to me whether spell slots created through Flexible Casting count as Warlock spell slots for the purpose of things such as Bewitching Whispers. Can Flexible Casting spell slots be used with this invocation?

Can a multiclass sorcerer make spell slots for their other class using sorcery points?  For example: can a multiclassed sorcerer 3 / warlock 1 use Flexible Casting to create a warlock spell slot?


I want to calculate the complexity of an algorithm for which i need to mention each line of algorithm cost and frequency as a separate cell for each row of algorithm. I intend to write it in the fashion as shown at the end. I am using the algorithmic package, using it inside the tabular is giving many errors. I hope there is some way to do it.  ___________________________ |1| x=0         | c | 1   | |2| y=0         | c | 1   | |3| for z=0 to n| c | n+1 | ---------------------------   not the duplicate of the question marked, as it says to write the algo in a column while i want each row to carry an each line of algorithm, that's why I have also added the same question in my comments for ease of understanding.

Let us consider the following code and the algorithm corresponding to it    \documentclass{article}   \usepackage[utf8]{inputenc}    \usepackage[]{algorithm2e}     \begin{document}     \begin{center}    \begin{algorithm}[H]     \KwData{this text}     \KwResult{how to write algorithm with \LaTeX2e }     initialization\;     \While{not at end of this document}{      read current\;      \eIf{understand}{              go to next section\;       current section becomes this one\;       }{       go back to the beginning of current section\;      }     }     \caption{How to write algorithms}    \end{algorithm}    \end{center}    \end{document}   Which gives the following     I want to add running times for each step to my algorithm as shown below (for example)    So, I need to make my algorithm as a column in the table and one more column for running times of each step, how can I make my algorithm as a column inside a table?


I want to get the iterator for the element I'm testing for in binary-search. But it only returns a bool indicating whether it found the value or not. How to get the iterator?

I need a binary search algorithm that is compatible with the C++ STL containers, something like std::binary_search in the standard library's <algorithm> header, but I need it to return the iterator that points at the result, not a simple boolean telling me if the element exists.  (On a side note, what the hell was the standard committee thinking when they defined the API for binary_search?!)  My main concern here is that I need the speed of a binary search, so although I can find the data with other algorithms, as mentioned below, I want to take advantage of the fact that my data is sorted to get the benefits of a binary search, not a linear search.  so far lower_bound and upper_bound fail if the datum is missing:  //lousy pseudo code vector(1,2,3,4,6,7,8,9,0) //notice no 5 iter = lower_bound_or_upper_bound(start,end,5) iter != 5 && iter !=end //not returning end as usual, instead it'll return 4 or 6   Note: I'm also fine using an algorithm that doesn't belong to the std namespace as long as its compatible with containers. Like, say, boost::binary_search.


When I try to call a method from another java class within same package, I get the below error: PASSED: validateLogin FAILED: test java.lang.NullPointerException at assembly.SlackInviteFlowValidation.selectManageSideNavbar(SlackInviteFlowValidation.java:130) at assembly.SlackUpgradeEditViewFlow.test(SlackUpgradeEditViewFlow.java:28) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source) at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source) at java.lang.reflect.Method.invoke(Unknown Source) at org.testng.internal.MethodInvocationHelper.invokeMethod(MethodInvocationHelper.java:124) at org.testng.internal.Invoker.invokeMethod(Invoker.java:583) at org.testng.internal.Invoker.invokeTestMethod(Invoker.java:719) at org.testng.internal.Invoker.invokeTestMethods(Invoker.java:989) at org.testng.internal.TestMethodWorker.invokeTestMethods(TestMethodWorker.java:125) at org.testng.internal.TestMethodWorker.run(TestMethodWorker.java:109) at org.testng.TestRunner.privateRun(TestRunner.java:648) at org.testng.TestRunner.run(TestRunner.java:505) at org.testng.SuiteRunner.runTest(SuiteRunner.java:455) at org.testng.SuiteRunner.runSequentially(SuiteRunner.java:450) at org.testng.SuiteRunner.privateRun(SuiteRunner.java:415) at org.testng.SuiteRunner.run(SuiteRunner.java:364) at org.testng.SuiteRunnerWorker.runSuite(SuiteRunnerWorker.java:52) at org.testng.SuiteRunnerWorker.run(SuiteRunnerWorker.java:84) at org.testng.TestNG.runSuitesSequentially(TestNG.java:1208) at org.testng.TestNG.runSuitesLocally(TestNG.java:1137) at org.testng.TestNG.runSuites(TestNG.java:1049) at org.testng.TestNG.run(TestNG.java:1017) at org.testng.remote.AbstractRemoteTestNG.run(AbstractRemoteTestNG.java:115) at org.testng.remote.RemoteTestNG.initAndRun(RemoteTestNG.java:251) at org.testng.remote.RemoteTestNG.main(RemoteTestNG.java:77) I am using selenium Webdriver and TestNG framework. Here is my code where SlackInviteFlowValidation & SlackUpgradeEditViewFlow are from same package and extends Base class where in Base class has Chrome driver initailzation and login Functionality only. // Class SlackInviteFlowValidation // Function to validate landing page of Manage public void selectManageSideNavbar() throws InterruptedException {     slackobject.avatarIcon().click();     slackobject.AdminText().click();     slackobject.UsersText().click();     slackobject.ManageText().click(); }  //Class SlackUpgradeEditViewFlow // Creating object for class SlackInviteFlowValidation SlackInviteFlowValidation slackinvite = new SlackInviteFlowValidation(); public class SlackUpgradeEditViewFlow extends Base{ public static Logger log = LogManager.getLogger(SlackInviteFlowValidation.class.getName());  public SlackIdentityObjects slackobject;  SlackInviteFlowValidation slackinvite = new SlackInviteFlowValidation();  @BeforeTest public void init() throws FileNotFoundException, IOException {     driver = initializeDriver();     slackobject = new SlackIdentityObjects(driver); }  @Test public void test() {     try {         slackinvite.selectManageSideNavbar();     } catch (InterruptedException e) {         e.printStackTrace();     } }

What are Null Pointer Exceptions (java.lang.NullPointerException) and what causes them?  What methods/tools can be used to determine the cause so that you stop the exception from causing the program to terminate prematurely?


Is Cartesian product of two uncountable sets uncountable? Suppose we have a set of real numbers $R$, Can't it be shown that $R$ is uncountable by Cantor's diagonalization method, so it follows that the Cartesian product of two sets of real numbers in uncountable?

My hypothesis is that $\mathbb{R \times R}$,  the set of all pairs $(r_1, r_2)$, of real numbers is uncountable. I understand that the set of all pairs of natural numbers is countable. But could someone explain why the set of all pairs of real numbers uncountable? I am having trouble proving it using diagolization


my daughter prepares meals for her small catering business. After she prepares them and stores them in plastic containers she stores them in our fridge which is taking up too mush space. They foods are cooked and vary from pasta to vegetables to seafood and other meats. Sometimes she does not deliver these prepared meals until the 2nd or 3rd days how soon must she deliver them to her clients before they spoil.

How do I know if a given food or ingredient I have is still good, or if I should discard it?  How can I best preserve a food or ingredient?     This broad question is intended as a "general reference" question to quickly answer many how long will food keep for? questions. Please feel free to edit this question to expand and clarify as needed.


I was messing around with my settings in single creative mode, and I came across these really weird video settings, and I immediately thought what the heck!  They made the game hard, and it was almost impossible to tell between certain blocks.  It made no sense.

In the new snapshot of minecraft (13w36b) there is a super secret setting in the options menu. when hitting the button an enderman-ish sounds play. Does it do anything or is it just a sound?


I am running a logit model trying to predict purchases on a dataset including change variables, i.e. I have a dataset of this kind:                webvisits.month1  webvisits.month2 webvisits.month3 Purchase contract1          34                   21            22          0 contract2          11                   2             2           1 contract3          9                    22            17          1 contractn          5                    44            42          0   The model is not performing well at all, would it be a good idea to try and normalize my variables? Would that affect the outcome? If this is the case, should I normalize them by month (considering the values by variable webvisits.month1, webvisits.month2 and so on) or rather by contract (e.g. considering the distribution contract1 [34,21,22,0], contract2 [11,2,2,1] and so on? Thanks, hope this makes sense.

In some literature, I have read that a regression with multiple explanatory variables, if in different units, needed to be standardized.  (Standardizing consists in subtracting the mean and dividing by the standard deviation.)  In which other cases do I need to standardize my data?  Are there cases in which I should only center my data (i.e., without dividing by standard deviation)?


The problem of $k$ element subsets of an element set such that no two elements are consecutive can be solved using stars and bars approach. But, can it be also solved using recurrence relations and generating functions? Note that the problem of any element subsets can be solved using recurrences which gives a fibonacci number answer. But what about this problem? I think this is not duplicate problem. Any hints? Thanks beforehand.

I am trying to find the formula for the number $f(n,k)$ which is defined as the number of $k$-subsets of $[n]$ in which no two elements are consecutive numbers in $[n]$.  From the simple thinking I had made up following recursion:  $$f(n,k) = f(n-1,k) + f(n-2, k-1) $$  This is true since I can construct without last element of $[n]$ then make up $k$-subsets, then otherwise must contain the last element of $[n]$ then construct remaining $k-1$ elements among $[n-2]$ since with the last one, I can't use $n-1$.  However, I had never learned any techniques regarding changing those recursion into a well-summarized formula in terms of $n$ and $k$.  Any guidance would be appreciate.


I am trying to automate a minimal form interface using Selenium to capture an element & later Java code.  But the challenge is the minimal form has only one input container which is constantly changing and the input container generates dynamic id's so finding the element by id name is not possible.  The input container cannot be mapped with xpath because xpath also uses the id  eg. //md-select[@id='select_15'].

There is a type and search drodown which will appear after user type in the value. I need to click on the dropdown which contains the name of the drop down field.   The problem here is that there is no unique attribute present (No unique class, no unique name) & the id keeps on changing after every login so cannot take id also.


While trying to ask a question, one could get:  We are no longer accepting questions from this account. See the Help Center to learn more.  This is of course something counterproductive towards a single user, but for the best of the community. Seeing as individual users are barred from asking further questions they go looking for ways to regain that ability. The solution for that always boils down to getting a positive record again. Something that can be achieved by improving ones existing questions, or adding new positively scored questions to your account. The latter should not be a viable option, as the user is at that point banned from asking new questions, with the exception for one new question every 6 months. Recently in a comment thread a user proposed the following way to redeem yourself from a question ban:  ...you can ask questions anonymously(without logging in somesites), then after receiving the upvotes (1 is sufficient), you can request a merge which will be done immediately  It is true that in some cases an . This is something that isn't very well documented at all (which might be for the best of it). I wonder if this is currently a viable option to get your question ban lifted. I, for obvious reasons, don't feel like testing this in practice. Therefore any "official" answer is appreciated.

currently restricts recreated accounts to "posting only one question per week..."  I would like to understand why this rate was picked, and not, say, once a day or once a month?  The reason why I ask is that some users limited or banned at Stack Overflow . I expect that learning more about the limitation would help me better understand its impact on Programmers.


Is there any difference between a directory name such as  mydirectory   and  mydirectory/   I noticed this happens when I execute ls in some directories - some of the directory names have a slash and some don't. This is problematic because if I want to access a file contained in a directory, I may need to add a slash at the end:  vi $mydirectory"/"$myfile   or simply do   vi $mydirectory$myfile

Possible Duplicate:          Most commands I use in linux behave exactly the same whether I include the trailing slash / character on the end of a directory name or not.  For example:  ls /home/cklein ls /home/cklein/  cp foo bar cp foo/ bar/   When does this trailing slash matter?  What is the semantic meaning of the trailing slash?


I've had base units explained to me as units that cannot be broken down into a combination of other units. The Ampere is considered a base unit, however it can be written as coulombs per second.  Is there a better explanation of SI base units?

The metre is the length of the path travelled by light in vacuum during a time interval of 1  ⁄ 299792458 of a second. – 17th CGPM (1983, Resolution 1, CR, 97),    The meter (or metre) is considered one of the seven base units in SI, but since it depends on what is “a second”, shouldn’t it be a derived unit? Why is the meter considered a base SI unit, even though it depends on the definition of a second?  I am aware that other base units such as the ampere also depend on other base units (namely meter, kilogram and second), and this just increases my confusion even more. Perhaps my question boils down to: What property must a unit have so that it is called a base SI unit?


I found this question in an online test.     We're really looking forward to going on holiday.  (Right answer)   or     We're really looking forward to go on holiday.    (Wrong answer)   I do not understand why the first one is the right answer.

Should I say      I look forward to hearing from you   or     looking forward to hear from you?   I have doubt because I know that the form of a verb is "to+ infinity" without the addition of the -ing that changes it to become a noun.


How to show $\sqrt{3} + \sqrt{2}$ is algebraic? Is there a way I can do this without trial and error? Thanks.

In Abbot's Understanding Analysis I am asked to show that $\sqrt{2}+\sqrt{3}$ is an algebraic number. I have shown that those two are algebraic separately (that was simple), but I can't figure out what to do to show that their sum is algebraic, too. For example, I tried $(\sqrt{2}+\sqrt{3})^{2}=5+\sqrt{24}$ and then I tried to think of a polynomial of form $ax^2-bx^{0}=0$ e.g. $c(\sqrt{2}+\sqrt{3})^{2}-c(5+\sqrt{24})=0$ that would work, but couldn't find the $c$ value that would make $b=c(5+\sqrt{24})$ integer, but couldn't find one. Maybe I can somehow conjecture that the sum of two algebraic numbers must be algebraic, too, but I was wondering if there's a way to find a polynomial to show this. Thanks!


I recently put together some Google n-grams for a short piece on the transition of the word data into a singular (mass) noun: . There was one peculiar finding:  When starting a sentence, the trend reverses. "The data are" and "Data are" are approximately twice as common as "The data is" and "Data is". ()  The best suggestion for why, is that the writer is more careful at the beginning of the sentence (). Are there any actual grammatical reasons? Or, do you have any other guesses as to why the trend reverses? If so, I'll add them to the story - and link back to here. meta:* I'm not asking about the difference between data is and data are, so this question is not related to the earlier ones on ELU.

I know that the singular of data is datum. I know that data is a plural.   However, common usage of the word "data" suggests it is used as a "collection of data".     Here is [the collection of] data.   In which case, is the word data now a singular again, or still the plural? If so, what is the correct use of the word data and datum now?


I was trying to help this person with his question.    Showing continuity was relatively easy, but I'm having trouble with showing that the function is not differentiable at $c$.  I tried using the hint and using one-sided derivatives, but all I got was that $F'(x) = f(x)$ for all $x\neq c$, and all I managed to show from that was that $\lim_\limits{x \to c} F'(x)$ does not exist. But all that showed was that the derivative of $F$ wasn't continuous at $c$, not that $F$ wasn't differentiable at $c$.   So I tried going down to Riemann sums. But I got stuck when showing that the last bit was a contradiction, since the absolute value of an integral is at most the integral of the absolute value of the integrand, not the other way round. I was wondering if it's salvageable, or if there are other errors I didn't see. Thanks!

Suppose $f(x)$ is continuous on $[a, b]$ except at a point $c$ in $(a, b)$ at which $f(x)$ has a jump discontinuity. For $x$ in $(a,b)$, set $F(x)=\int_a^xf(t) \, dt$. Show that $F(x)$ is continuous but not differentiable at $x =c$.  Hint: first explain why $f(x)$ is integrable on $[a,b]$, then consider one-sided derivatives of $F(x)$ at $x =c$.  I don't know how to step up because it seems conflict to me. $f(x)$ is not continuous because it has a jump but I have to prove it continuous, how? Can someone guide me, please.


\documentclass[a4paper]{report}  \usepackage{mathrsfs}  \begin{document}  \begin{equation} \sum_{a',a'' \in \mathscr{A}} c_{a'}^* \, c_{a''} \end{equation}  \end{document}   results in this output:  .  I want the c's to start right after the sum sign, i.e. ignoring the subscript. If I encapsulate the subscript within \mathrlap{} from mathtools, however, it also messes up the placement of the sum sign. Thus, in essence, I want an instruction for the c's to ignore the vertical spread of the sum's subscript, but not the sum sign itself.

I am actually new to latex, so this is very basic and ridiculous question. However, I cannot eliminate the blank between f(e) and the summation symbol. Besides, the equal sign is so far from the summation symbol. How can I solve these ?  Latex Code:   \sum_{e \, into \, node \, v} f(e) = \sum_{e \, out \, of \, node \, v} f(e)


I insatlled matplotlib using followig command :      sudo apt-get install python-matplotlib   And after that I run a sample matplotlib program using python abc.py. It works well. But when I run it in python3 abc.py. It gives missing module errors. I don't know how to this install work? Help me with this problem.  PS : I don't want to use python2.7 anymore. So any suggestion with removing or replacing python3 with python2 will be good.

I have been through the process of installing matplotlib on my Ubuntu 12.04 computer. However, when I try to run a test program, I get the following error:   Traceback (most recent call last):   File "../py33/test.py", line 2, in <module>     import matplotlib.pyplot as plt ImportError: No module named 'matplotlib'   I am trying a sample program from matplotlib's website (basic_example). I just don't understand why it says there is not module matplotlib, even though I have definitely installed it (using sudo apt-get install python-matplotlib, and have done sudo apt-get build-dep python-matplotlib; I also tried pip install matplotlib, as I was told to do that, after installing Python itself, if I wanted to install other binaries).


I have a precursory research – that is, an article posted in my website to know what I want to pursue – and want to send to a professor to have his opinion. However,  to ask him if he has time to read my ideas first before sending links to long blog posts.   I wonder why that is a case. I understand that this is to show that I respect his time – a professor has many duties – but I think in the end it depends on the interestingness of the content. If it is interesting enough, then no matter how long it is, it is still, well, interesting. And I think this factor is basically the relevance of my email to his work. As explained in , as long as the email is relevant it can be answered.   In my case, it has raised some interests to others in tangient fields, and matches one of his research interests, so I don't think there should be a problem. What may be a problem is that he may be reluctant to click on an unsolicited link, or the articles are long. But I suppose this is a normal thing that researchers do all the time? All of the problems here – sending unsolicited email to ask for opinion, putting the article in a link or attachment to keep the email short, putting the ideas in blog when they are just initial observations – don't seem to be problem to me.   Think of the email like this very question: I ask you unsolicitously, you may have a lot of duties, and there are three links on it. If I don't need to worry whether I am wasting your time reading this question, then why should I worry I'm wasting his time?  The email is much shorter than this question. I don't see why there should be extra cautious.  So why does the person advise this? The full draft of the email can be read .    Minor question: Should I put tracking links?

I wonder how a researcher send an unsolicited email to another one asking for feedback to their work. I guess it will be something like this?  Hello Dr. X To introduce myself, I am Y, in institute Z. I'm sorry if this email is not convenient at this time, but my work about A is highly relevant to your work in B, so I think it will be interesting to you too. If possible, can you take a look at it and tell me what you think? Here is the link:  Thank you for your reading, hope you enjoy it.  I wonder if the summary/abstract should be included in the email too, since the principle for  is to show everything you know about it. Maybe it's not necessary, since the title of the link should prove its interestingness nevertheless? I'd like to have your confirm. I'm also interested in the case where Y has no Z, and the link is just a collection of observations posted in a blog, not a full paper with proper citation and literary review. It is possible that the observations may have been covered in the field, but Y isn't aware of that yet. I also think that if the link is interesting enough, then putting a tracking method in there is fine too? Even if they finds out, they wouldn't feel insulted either, because they find that the link is indeed interesting.  Related: •  •  •


Recently, I stumbled upon this problem, , both here at MSE and somewhere surfing the web. I tried to solve it but don't know how. Although I can't remember where I found it, I doremember the question saying to solve the equation for $x$ rather than to determine whether some sort of solution existed. So by that, I presume that there is a such solution that I am not seeing.  I tried the following: $1^2$ mod $23$, $2^2$ mod $23$, $3^2$ mod $23$, $...$ , $22^2$ mod $23$. Following this procedure did not yield an answer of $49$. Can anyone show me how a solution is determined because it has been over 2 days and it is driving me crazy from my inability to see the solution.

What is the procedure to solving $x^2$ $mod$ $23 = 7^2$? According to WolframAlpha, there is no integer solution but I am completely confused as to what steps was taken to determine that.  Before asking the question, I did try to solve this using brute force by plugging in some arbitrary numbers to see whether the square of that number mod $23$ gave me a remainder of $49$ but the procedure was quite tedious. Hence the reason I turned to WolframAlpha.   Going back to the question, I want to know how WoflramAlpha determined that there was no integer solution to solving for $x$.


I have written this query,       $sql = "SELECT `candidates`.`candidate_id`, `candidates`.`first_name`, `candidates`.`surname`, `candidates`.`DOB`, `candidates`.`gender`, DATE_FORMAT(NOW(), '%Y') - DATE_FORMAT(`candidates`.`DOB`, '%Y') - (DATE_FORMAT(NOW(), '00-%m-%d') < DATE_FORMAT(`candidates`.`DOB`, '00-%m-%d')) AS `age`, `candidates`.`talent`, `candidates`.`location`, `candidates`.`availability`, `candidate_assets`.`url`, `candidate_assets`.`asset_size`             FROM `candidates`             LEFT JOIN `candidate_assets` ON `candidate_assets`.`candidates_candidate_id` = `candidates`.`candidate_id`             WHERE `candidates`.`availability` = 'yes'";              if(isset($type)) {                 $sql .= ' AND candidates.talent = '. "$type";             }              if(isset($skill))             {                 $sql .= ' AND candidates.skill = '."$skill";             }              if(isset($gender))             {                 $sql .= ' AND candidates.gender = '."$gender";             }      $query = $this->db->query($sql);      return $query->result_array();   I wanting to  the $type, $skill and $gender variable to passed as strings that whatever the variables contain are returned in the sql as wrapped in "" is this possible? How would I do this?

If user input is inserted without modification into an SQL query, then the application becomes vulnerable to , like in the following example:  $unsafe_variable = $_POST['user_input'];   mysql_query("INSERT INTO `table` (`column`) VALUES ('$unsafe_variable')");   That's because the user can input something like value'); DROP TABLE table;--, and the query becomes:  INSERT INTO `table` (`column`) VALUES('value'); DROP TABLE table;--')   What can be done to prevent this from happening?


In fact I want to include my list of abbreviations in my table of contents. But when I write my latex code this list of abbreviations isn't showed in the table of contents. I have used  \nomenclature which will automatically print that nomenclature in the list of abbreviations which were displayed using \renewcommand{\nomname}{List of abbreviations}. Here is the code:  \documentclass[12pt]{report} \usepackage{lipsum} \usepackage[french]{babel} \usepackage{unnumberedtotoc} \usepackage[automark, plainheadsepline, headsepline, plainfootsepline, footsepline, markcase=ignoreupper]{scrlayer-scrpage} \clearpairofpagestyles \ihead*{\leftmark} \cfoot*{\pagemark} \setkomafont{pageheadfoot}{\scshape} \usepackage{titlesec} \usepackage[a4paper,right=20mm,left=25mm,top=25mm, bottom=26mm,% head=14.5pt,%<- new  ]{geometry} \titleformat{\chapter}[display]  {\normalfont\huge\bfseries}{\chaptertitlename\ \thechapter}{20pt}{\Huge} \titlespacing*{\chapter}{0pt}{0pt}{20pt} \titleformat{\paragraph} {\normalfont\normalsize\bfseries}{\theparagraph}{1em}{} \titlespacing*{\paragraph} {0pt}{3.25ex plus 1ex minus .2ex}{1.5ex plus .2ex} \begin{document} \tableofcontents \addchap{Publications} \addchap{Acknowledgement} \renewcommand{\nomname}{List of abbreviations} \chapter{Introduction} \lipsum \lipsum \chapter{state of art} \lipsum \chapter{theory} \lipsum \end{document}

Is it possible to create a list of all the figures at the end of a document (this I can do) and make it appear in the table of contents?  So in the the table of content there will be a line saying List of figures ... 19 for example?


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

Takeaway: Are 4 inexperienced users more reliable than 3 experienced users? A high rep doesn't ensure you are smarter, but it makes you the safer option.    I went to SuperUser to see what suggestions can be found for different Malware-removal Applications.  was right on target, and sported five answers, with a total of 9 up-votes.  All of the answers were provided by low-rep users, and that leads me to recognize that the up-votes may be a similar case. Just as answers aren't always equal, neither should up-votes be. The top answer currently has 4 up-votes, and the second most popular answer currently has 3 up-votes. The people who voted in the 3, may be more reputable than those who voted in the 4. Am I communicating this clearly?  I'm not asking that we be told who voted for a particular question, but I am asking that we be told what type of reputation they had. If the 4 votes come from 4 users with less than 300 rep, and the 3 votes came from two users with 300 rep and 1 with 10k rep, the 3 votes should appear stronger by the standards of the system.  Right now I'm worried about accepting the top-voted solution simply because I fear the up-votes may be from people with similar rep to those providing the answers - that doesn't make them wrong, only less-reliable by the standards of the stackexchange engine.  Can we see the sum of rep for  the votes? (Data in parenthesis would not be visible)   4 Votes (Ted • 72 | Bill • 183 | Carl • 423 | J • 100) = Power of 778 3 Votes (Bob • 19,123 | TJ • 283 | Mike • 8,923)       = Power of 28,329  So in this case, you wouldn't see who voted, only that their rep-sum was 778 and 28k.   4 Votes : 778 3 Votes : 28k  I'm not tied to this way of indicating the vote-power, but some method is better than no method.  Another concern is that higher-rep users (having been around longer) participate in voting less-frequently than new-comers do. After all, we're not trying to gain badges, build rep, etc. As a result, it's more likely that a low-rep users will cast a vote than it is a high-rep user. Does that follow logically?    Rebuttal     Reputation (From the SO-FAQ)      Reputation is a (very) rough measurement of  how much the Stack Overflow community trusts you. Reputation is never given, it is earned by convincing other Stack Overflow users that you know what you're talking about. (emphasis added)    "Rep has nothing to do with credibility, competence or knowledge!" - John Smithers     I agree. But it does have to do with "how much the SO community trusts you." Granting that, some votes are more trustworthy than others. Because they come from users who have convinced "other SO users that they know what they're talking about."  "The purpose of anonymous voting is that all votes are valued equally, whether they come from Jon Skeet or from some new person." - devinb     That is clearly not the case though. If SO operates by labeling some users more "trusted" than others (which it does), then that would mean some votes are trusted more than others. I would trust Jon Skeet to suggest a good programming book than I would two freshmen. It's irrational to suggest Jon Skeet will offer the best recommendation but that isn't what is being argued here. Only that Jon Skeet is the safer choice given his reputation.  "Just because a person has reputation does not mean they have more technical knowledge." - yshuditelu     I agree, but it does mean they are the safer source than somebody with no rep. That is, according to the SO-system.


Tonight, I had a bard cast Hungar of Hadar into a room, then circle back through the dungeon to flank while maintaining concentration on the spell. The spell has a range of 150 feet. Is it possible to maintain concentration on the spell despite losing line of sight and moving beyond the 150 foot casting range?  Concentration was allowed despite exceeding the original casting range. One person questioned the ruling, so I am curious if there is an official stance on the subject.

Does going outside the range of the spell or breaking line of sight between the caster and target break concentration or otherwise affect control over the spell?  For example, a Heat Metal spell has a range of 60 ft. If I cast the Heat Metal spell on a an armored foe, and that foe runs outside the range of the spell (60 ft), or around the corner, does that break concentration and end the spell? Heat Metal also allows you to use a bonus action to cause the 2d8 of damage — would exercising that option be prevented by being out of range or line of sight?


We, bayesians, usually use non-informative priors for the parameters like  $p(\beta)\propto 1$.  Someone told me that such a flat prior is informative to some extent for non-linear functions of the parameters $\beta$. I thought this sort of prior was always uninformative for any kind of functional form.   I would appreciate some clarification on this point!

Inspired by a comment from :  What do we consider "uninformative" in a prior - and what information is still contained in a supposedly uninformative prior?  I generally see the prior in an analysis where it's either a frequentist-type analysis trying to borrow some nice parts from Bayesian analysis (be it some easier interpretation all the way to 'its the hot thing to do'), the specified prior is a uniform distribution across the bounds of the effect measure, centered on 0. But even that asserts a shape to the prior - it just happens to be flat.  Is there a better uninformative prior to use?