I'm struggling with using macvim and mactex on M1 MBA. Here is what I've done.  Install macvim (via homebrew, probably). Install . Install TeXShop 4.58, Ghostscript-9.53.3-Full.pkg, and MacTeX-2020-Universal.pkg (see ).  However, on my macvim, the following errors occur.  Note: I tested x86_64 and arm64 support described at the bottom of . Note2: which latexmk gives latexmk not found. EDIT: I've installed latexmk via Tex Live Utility but still the command latexmk does not work.  EDIT2: I manually adding path in ~/.zshrc as export PATH="/usr/local/texlive/2020/bin/x86_64-darwin:$PATH", which solves the problem.

I've installed the MacTex bundle on my machine. When I try to run $latexmk I get a 'command not found'.  I already reinstalled the latexmk bundle in TeX Live Utility. Both universal-darwin and X86_64-darwin are installed. But I still get the same error.  I would be very thankful for any solutions.


The navigation's contrast is too low, which hampers my ability to quickly scan the navigation. I find myself many times having to concentrate and read the section I'm in. I think part of the problem is that the community logos bleed underneath the main navigation. Also the navigation text is about the same height as the community logos.  When a link is "selected/active", text state though turns a light blue that, in my opinion, is really close to the header background color. It becomes hard to read, especially links such as "Questions" and "Tags".  I vote to insert some sort of color background on selected/active links to help push it forward from the background.

I find the .youarehere a styling for the main navigation links causes the text to be a little difficult to read on the also-blue header background. Could we give it a little bit of background colour or something else that would provide more contrast?  For example:    which is the product of the following CSS*:  .nav ul li {     margin: -2px 10px 0 0;     padding: 5px; }  .nav ul li.youarehere {     background-color: rgba(0, 80, 112, 0.25);     border-radius: 5px; }  .nav ul li.youarehere a {     color: #A1E9FF; }   *For bonus points, also reduce the line height for the codeblocks!


Let $x>1,n>2$ be positive integers. I come across the following problem: Is $$GCD(2^n,(x^2+1)^{n-1})=1$$ or $2^n$ is relatively prime to $(x^2+1)^{n-1}$ ? Is $$GCD(x^{2n},(x^2+1)^{n-1})=1$$ ? NB: $GCD$ is the greatest common divisor.

If $\gcd(a,b)=1$, then $\gcd(a^n,b^n)=1$   This seems clear, but I don't know how to prove this..  I was trying to show this by induction such that if $a^{n+1}$ = $rs$ and $b^{n+1}$ = $rt$, then $s,t$ are divisible by $a,b$ respectively, but i think this is a wrong way..


I have a question regarding the sum of this series: $$\frac{3}{1!+2!+3!} + \frac{4}{2!+3!+4!} + \cdots + \frac{2008}{2006!+2007!+2008!}$$ My approach: I found that this sum is equal to: $$\sum_{n=3}^{2008}\frac{n}{(n-2)!+(n-1)!+(n)!}$$  I reduced it to : $$\sum_{n=3}^{2008}\frac{1}{n(n-2)!}$$  Please suggest how to proceed further.

Find the sum to $n$ terms as well as the sum to infinity of the series:  $$\frac{1}{3} + \frac{1}{4\cdot 2!} + \frac{1}{5\cdot 3!} +\cdots.$$  I was trying this question many times but I didn't get the answer. I was using geometric series formula, but it was not applicable here...I don't know where I have to start, and I don't know any hint about this series....  If anybody helps me, I would be very thankful to him.


So I draw my graphs like  \documentclass{standalone} \usepackage{tikz}  \begin{document}  \begin{tikzpicture}             \tikzset{Bullet/.style={fill=black,draw,color=black,circle,minimum size=3pt,scale=0.75}}             \node[Bullet,label=left :{$u_1$}] (u1) at (0,2){};             \node[Bullet,label=above:{$u_2$}] (u2) at (1,3){};             \node[Bullet,label=right:{$u_3$}] (u3) at (2,2){};             \node[Bullet,label=right:{$u_4$}] (u4) at (2,0){};             \node[Bullet,label=left :{$u_5$}] (u5) at (0,0){};             \draw[thick] (u1)--(u4)--(u5)--(u3)--(u2)--(u1); \end{tikzpicture}  \end{document}   I want to set individual colours for each of the nodes/vertices. And I can, but it seems a bit clunky.  \documentclass{standalone} \usepackage{tikz}  \begin{document}  \begin{tikzpicture}             \tikzset{Bullet/.style={fill=black,draw,color=red,circle,minimum size=3pt,scale=0.75}}             \node[Bullet,label=left :{$u_1$}] (u1) at (0,2){};             \tikzset{Bullet/.style={fill=black,draw,color=orange,circle,minimum size=3pt,scale=0.75}}             \node[Bullet,label=above:{$u_2$}] (u2) at (1,3){};             \tikzset{Bullet/.style={fill=black,draw,color=yellow,circle,minimum size=3pt,scale=0.75}}             \node[Bullet,label=right:{$u_3$}] (u3) at (2,2){};             \tikzset{Bullet/.style={fill=black,draw,color=green,circle,minimum size=3pt,scale=0.75}}             \node[Bullet,label=right:{$u_4$}] (u4) at (2,0){};             \tikzset{Bullet/.style={fill=black,draw,color=blue,circle,minimum size=3pt,scale=0.75}}             \node[Bullet,label=left :{$u_5$}] (u5) at (0,0){};             \draw[thick] (u1)--(u4)--(u5)--(u3)--(u2)--(u1); \end{tikzpicture}  \end{document}   What I'd really like is to be able to get it looking like this, to highlight isomorphisms:

How do I pass two parameters to a tikz style?  I would like to do something like this:  \begin{tikzpicture}[     transformer/.style={draw, cylinder, gray!80, rotate=90, minimum height=#1, minimum width=#2},   And then, I want to use this style in a node:  \node [transformer{2.3cm}{1cm}] () at (0,0.6) {};


I am probably going to get massively downvoted for this but I feel strongly about it.  First a bit of background:  As a modern programmer you frequently work in a collaborative environment, not in a dark, dank broom closet. In this environment you get questioned about your tactics and methods continuously and are expected to always produce meaningful, constructive advice in return, even if the other individual imposing a question has flawed logic.  This is why I refuse to downvote on SO stating that I would rather talk to the OP/answerer and tell them what I see as wrong and work it out with them, concluding that downvoting creates an environment where knowledge is not passed on in a constructive manner. That is my own personal opinion and I expect no one else to share it.  However, back to the point:  Questioning and providing feedback has been going on fairly well for about the last 1 1/2  years until about now when moderators seem to be deleting my comments to a certain individual who basically finds my comments either non-constructive, offensive or spam.  I am not going to beat around the bush about this and instead just come out with it, this is a follow up to this:  and the entire situation that surrounds it.  I seem to have a misunderstanding of what exactly is constructive.  You see a couple of times today I have commented on answers by this guy asking about his logic, i.e.  I asked him why he said that distinct() was out dated without documented reason and why the aggregation framework was better despite distinct() being able to use indexes while $group in the aggregation framework not.  And here:  where I reasoned that the answerer did not truly read the question properly and that the OP was looking for a specific scenario.  In the end both of these threads were moderated, essentially (I believe) because I was able to prove my point so instead of launching into verbal abuse he just got a moderator to delete the comments.  He, however, didn't flag when he proved me wrong and questioned my logic on this question:   In all fairness I flagged his comments on that question asking the moderators why he was allowed to flag my comments, get them deleted but then do it to me.  I didn't flag them because I was offended or found the comments non-constructive. I wanted to show that this is part of SO.  But even here:  he seems to think he is right to do it while others are wrong to question him.  At the end of the day I feel as though sometimes moderators should tell people that if a comment is not specifically offensive, spamming or non-constructive it should be left alone.  I could have just downvoted and not told the guy nothing what was wrong, but I didn't. I decided to reason with him and for it I am the one being moderated?

I'm probably missing something obvious here but why is it possible for comments to be deleted?  I was recently engaged in a discussion on Stack Overflow and the other party later selectively deleted some of their comments. The context of the discussion thread then became somewhat ambiguous.   If a comment is deleted is a reason provided? Is the process of comment deletion peer reviewed? I appreciate it could be useful for good house-cleaning but it can also lead to disjointed conversations.  I know that commenting is intended to annotate rather than chatter, but there's still some back and forth involved.  Sorry for the newbie question and please signpost me if this has been covered elsewhere.


If photons going c have no local time or distance 'perception' why isn't the same true for us as we're going c relative to them?

I have just started special theory of relativity. The limiting speed known as speed of light fascinated me most. I asked my teacher:      Consider two massless objects moving in the same direction at the speed of light. What would be their relative velocity w.r.t each other?   My teacher tells me that their relative velocity would be zero. But then the speed of light is universal constant regardless of the motion of its frame of reference, so shouldn't their relative velocity be $c$? What is their relative velocity and how? Do objects moving at the speed of light obey law of addition of velocities?


My mother had a Schengen visa, which she applied for at the Swiss embassy in India. Validity is for 6 months (01-Mar-2013 to 31-Aug-2013) with a single entry visa, She has already spent 88 days in Switzerland and came back to her home country (India), but wants to apply for another Schengen visa at the Swedish embassy in India; validity would be 90 days from 11-Aug-2013 with a single entry visa.  I've heard it's not possible to apply for a new Schengen visa until the old one expires. Is this true? What are her options?

I'm a citizen of Ukraine planning on visiting Italy early in October for tourism. Later that month I'm accepted as a speaker at the conference in Prague, Czech Republic. Both countries are members of Schengen agreement and a visa is required for me to visit them. Therefore, I need to visit Schengen countries 2 times and I need to get my visas ASAP (to confirm my talk to the conference organizers, as well as to avoid overpaying for hotels/flight tickets).   I've heard a number of times that a single person can't apply for a Schengen visa if already in possession of one, but I'd like to clarify this. Say, I've got a visa from Italy for the period of October 1st - October 14th. Can I get another one from Czech Republic for October 25th - October 30th before I visit Italy? Would the answer be different if I were to visit the second country (CZ) on October 13th - October 20th, thus, having a single day overlap between these visits. It would be of a tremendous help if you could link to the official documents that prove your point, but I'd certainly appreciate answers even without such links.  Both times I'm going to apply for a short-term tourist visa covering the dates of my travel. If the answer to both questions above is no - would several visits to multiple Schengen countries over a short period of time be a valid reason to apply for a single multiple-entry visa that covers the whole period from October 1st to October 30th from Italy?


In Java, a large 2D array with sparse contents is rather memory inefficient, as it takes up a contiguous chunk of memory regardless of what data is actually stored in it.  I am looking for an alternative data structure that can hold elements in a positional, grid-like, way. I would preferably like the memory efficiency to be O(n) where n is the number of data elements actually in the structure.  Cheers!

I'm working on a project, written in Java, which requires that I build a very large 2-D sparse array.  Very sparse, if that makes a difference.  Anyway: the most crucial aspect for this application is efficency in terms of time (assume loads of memory, though not nearly so unlimited as to allow me to use a standard 2-D array -- the key range is in the billions in both dimensions).  Out of the kajillion cells in the array, there will be several hundred thousand cells which contain an object.  I need to be able to modify cell contents VERY quickly.  Anyway: Does anyone know a particularly good library for this purpose?  It would have to be Berkeley, LGPL or similar license (no GPL, as the product can't be entirely open-sourced).  Or if there's just a very simple way to make a homebrew sparse array object, that'd be fine too.  I'm considering , but haven't heard any opinions on its quality.


It is possible to change the username of a Stack Exchange account using the Android client?

It would be nice to update the profile page from within the app.  Perhaps not many people update their profiles more frequently, but when required to do so, I would prefer to do it from the app instead of the mobile browser.


I've these two lists a = [1, 2, 3] and another b = [4, 2, 1] I want this outcome by join these list like this (items in a with every item of b) : (1, 4) (1, 2) (1, 1) (2, 4) (2, 2) (2, 1) (3, 4) (3, 2) (3, 1)

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) ...]


Installed Ubuntu 12.04 64bit today, switched to Gnome Classic (no effects) and there is one thing that makes me crazy: I can't assign Super+L to Lock Screen function!  I go to System Settings -> Keyboard -> Shortcuts -> System, then I click on Lock Screen and press "Super + L", it appears in the list but when I press it again it doesn't work.  If I set it back to Ctrl+Alt+L it works again. Actually, I tried to set it to different Super + ?? combinations, and neither of them work.   if I assign Super+L to so other command, like Start Terminal, it works.

I want to change Key short cut  to  Super+L for LockScreen but it is not working. If I try any other combination like CTRL+ALT+L or CTRL+ALT+G , it works. Win+L combination used to work in 11.10.


I have a dataframe, i want to convert it to list,but data is change i dont know why

Consider the following code:   0.1 + 0.2 == 0.3  ->  false   0.1 + 0.2         ->  0.30000000000000004   Why do these inaccuracies happen?


I want to change my entire system from windows-1257 to utf-8 encoding..  But i'm facing some problems, When I change AddDefaultCharset from windows-1257 to utf-8 (in .htaccess)   It changes from (I want utf-8 result like this):    Mūsdienu civilizētajā pasaulē par valsti spriež pēc tā, kā tajā izturas pret saviem visneaizsargātākajiem sabiedrības locekļiem.   To this:  M�sdienu civiliz�taj� pasaul� par valsti sprie� p�c t�, k� taj� izturas pret saviem visneaizsarg�t�kajiem sabiedr�bas locek�iem.    HTML meta tag can be windows-1257 and UTF-8 (now it's utf-8) - it works fine with  AddDefaultCharset windows-1257   In database content looks like this: Mûsdienu civilizçtajâ pasaulç par valsti sprieþ pçc tâ, kâ tajâ izturas pret saviem visneaizsargâtâkajiem sabiedrîbas locekïiem.   I've tried:   Change content in database with iconv  Alter database/table + "CONVERT TO CHARACTER SET utf8 COLLATE utf8_unicode_ci;" (Maybe I used the functions wrong..)   Thank you for your time!

I'm setting up a new server and want to support UTF-8 fully in my web application. I have tried this in the past on existing servers and always seem to end up having to fall back to ISO-8859-1.  Where exactly do I need to set the encoding/charsets? I'm aware that I need to configure Apache, MySQL, and PHP to do this — is there some standard checklist I can follow, or perhaps troubleshoot where the mismatches occur?  This is for a new Linux server, running MySQL 5, PHP, 5 and Apache 2.


I've almost dropped 8,000 candies on the ground and he just keeps noming and I'm just wondering he actually does anything.

What is the point of throwing candy on the ground using the "Throw 10 candies on the ground"? All that seems to happen is that the text under it becomes more and more disappointed in me. ಠ_ಠ


I creating functions in my function.php and I have a question regarding passing local variables between functions.  Let say I have the functions below, A and B, and I have the variable $amount.  Now let's say in Function A, $amount changes according to certain conditions.  How do I make sure that the $amount used in Function B, is the updated variable and not just the variable I declared at the beginning.  I thought of using static or globals but I am not sure how this applies to a variable which is dynamic.   function A () {     $amount = 5;      if(isset($_POST['term_id']))     {       if ($_POST['term_id'] == '74' )         $amount = -20;        elseif ($_POST['term_id'] == '75' )         $amount = 500;     }    }    function B () {     echo $amount;   }   Edit:  To toscho, I understand the similarities between the two questions, but my variable is a dynamic variable, whereas the user's variable in the other questions is always constant.

I'm setting up a child theme in WordPress and I can't make add_action to be fired within functions.php.  Functions.php is called and I can run code from within. Any idea on what I'm doing wrong?  $debug_msg = "Hi there!";  function test_function() {     error_log($debug_msg, 0);  } add_action('init', 'test_function', 20);


As the title says, which incarnations of the Doctor lived longest and shortest? Here, I am not talking about age, but the period. For example, when The Master increased the age of The Doctor by 900 years, that would be counted as 1 year.

As of the second season of Matt Smith as , we've seen him give his age variously in a range between 900 and 1100 years (Note: I'm being deliberately vague here to avoid spoilers; being more accurate wouldn't add to my question).   As Matt's the eleventh doctor, this implies an average of 100 years of living per incarnation, assuming that the ages are somewhat accurate and not just fabrications.  Do we know the ages of any of the "other" Doctors?  How old was the Jon Pertwee Doctor, for example? Was he younger than expected, given that the regeneration was forced upon him?  William Hartnell's Doctor looks oldest physically, but did that correlate with actual age in any way?


I am in the middle of building my own PCB Board with different kind of MCUs (ESP32/8266, ARM Cortex, W5500) - Because each of these in a Dev Board are to big I want to just get the chips onto the board itself and make everything how I want it to be connected. But I only worked with dev boards before and programming/testing these is really simple but I realised I am really just a beginner in this field and so I don't know how I would get the code for the chips I created on the dev board onto the finished PCB. The only way I could say would build the code on a dev board, remove the chip and but it onto the PCB but if there is any kind of code problem I would really run into a pain to always remove the board. The other alternative I thought of would be to put a USB port - Because I don't want 3 USB ports for each chip I would also build in a jumper to change which chip I want to program. But I doubt that these are the "best" methods, so could help me there and give me an idea how I would do that ? I know helping a beginner isn't easy but I need to start somewhere to get better. Thanks !

I've designed a PCB for small scale production; currently I'm hand soldering them in batches of 20 at a time. This PCB uses an ATMEGA168 microcontroller which I program before soldering to the board - this method works well for me at the moment.  I'm looking at having a batch of 200 boards manufactured and assembled for me as the product I've designed seems to be quite popular. Would it be better practice to either include an ICSP header onto the board or keep on pre-programming the ICs myself? Re-programming of the board after manufacture or assembly isn't an intended or required feature.  I'm unsure of how this is done in a larger scale production environment? Adding an ICSP header would increase the cost of manufacture slightly so is pre-programming a standard practice?


When I view my scene in "User Perspective" mode, my graphics are glitched out (both solid and texture modes).  When I switch to ortho everything looks fine, so does the final render.  On the left is a plain old vanilla sphere (no modifications) - on the right is a cylinder with holes cut out.    I'm using 2x GTX-770 graphics cards (CUDA) in preferences.  Any Ideas?  Cheers.

I have recently started using blender and one of the models I'm working on has dark shadows along edges. I started this model from scratch. I can't remember them being there when I first started the model, but I had trouble joining areas together and think I've pressed something I shouldn't have. However, there are so many options I'm not sure what I did.  Here is an image of what I mean   The one on the left has the shadow. As a test I started a new model, which is on the right in the image, and as you can see it doesn't have any shadows.  Also, occluded vertices partially show through the model. Occlusion doesn't work properly.   In orthogonal view small darkened triangles appear along the the edges.    I don't really want to start the model again from scratch so any ideas on how to remove this shadow would be great. Thanks.


Here what I got :      The MiKTeX web service has rejected your request.  Possible reason:   too many requests arriving from your IP address.   Any ideas ? I thought it could come from the location of the server (how to change it by the way ?)  With best regards.  Klauss

I have a problem with the MiKTeX package manager. I receive the message:  The MiKTeX web service has rejected your request.  Possible reason: too many requests arriving from your IP address.   and:  HTTP Error 503. The service is unavailable.   I cannot even choose another repository. Maybe this all was caused by my having killed the process on my first try with ctrl-alt-del? Can it be that at the server a "zombie" of that killed process is still present? Will the problem go away by itself?


If $f_n$ is a sequence of continuous functions such that $f_n$ converges to $f$ uniformly . Does it imply that $\int _0^\infty f_n\to \int _0^\infty f$?  I think the answer is no though I could not find a counter-example. Because if $f_n\to f$ uniformly then $\int _0^\infty |f_n-  f|<\epsilon \times \infty $ which is undefined.

If $\displaystyle\{f_n(x)\}$ is sequence of continuous function on $\mathbb{R}$ converging uniformly to $f(x)$, then does $\displaystyle\lim_{n\to \infty} \int^{\infty}_{-\infty} f_n(x) dx\, = \int^{\infty}_{-\infty} f(x) dx\,$ hold? I know  it holds if we integrate over an interval of the form $[a,b]$ but not sure about improper integral!


I added operators for == and != to a class but it seems that they are not called when a object of that type is passed as a generic parameter. When I look at the decompiled code it looks like (object)a == (object)b.  Is it possible to use the operator overloads in this scenario? Thx!!  [TestMethod] public void Test() {   var a = new OperatorTest(13);   var b = new OperatorTest(13);    Assert.IsTrue(a==b);   TestGenerics<OperatorTest>(a,b); }  void TestGenerics<T>(T a, T b) where T: class {   Assert.IsTrue(a == b); //THIS FAILS! }  class OperatorTest {   private readonly int _value;    public OperatorTest(int value) {     _value = value;   }    public static bool operator ==(OperatorTest x, OperatorTest y) {     return x._value == y._value;   }    public static bool operator !=(OperatorTest x, OperatorTest y) {     return x._value != y._value;   } }

According to the documentation of the == operator in ,      For predefined value types, the   equality operator (==) returns true if   the values of its operands are equal,   false otherwise. For reference types   other than string, == returns true if   its two operands refer to the same   object. For the string type, ==   compares the values of the strings.   User-defined value types can overload   the == operator (see operator). So can   user-defined reference types, although   by default == behaves as described   above for both predefined and   user-defined reference types.   So why does this code snippet fail to compile?  bool Compare<T>(T x, T y) { return x == y; }   I get the error Operator '==' cannot be applied to operands of type 'T' and 'T'. I wonder why, since as far as I understand the == operator is predefined for all types?  Edit: Thanks, everybody. I didn't notice at first that the statement was about reference types only. I also thought that bit-by-bit comparison is provided for all value types, which I now know is not correct.  But, in case I'm using a reference type, would the == operator use the predefined reference comparison, or would it use the overloaded version of the operator if a type defined one?  Edit 2: Through trial and error, we learned that the == operator will use the predefined reference comparison when using an unrestricted generic type. Actually, the compiler will use the best method it can find for the restricted type argument, but will look no further. For example, the code below will always print true, even when Test.test<B>(new B(), new B()) is called:  class A { public static bool operator==(A x, A y) { return true; } } class B : A { public static bool operator==(B x, B y) { return false; } } class Test { void test<T>(T a, T b) where T : A { Console.WriteLine(a == b); } }


I'm trying to write about the Cantor set in LaTeX. It can be represented by a weird "C" symbol. It can be seen in this Wikipedia article:    I can't find the name of it anywhere. Does anyone know what it is and how to typeset it in LaTeX?  Thanks.  Edit: By going into the edit mode of the wikipedia article I found that the command is "\mathcal{C}". Still trying to find out the name though.

I know what my symbol or character looks like, but I don't know what the command is or which math alphabet it came from. How do I go about finding this out?


I have a condition within my js file where a file upload triggers my jQuery to append the following element for each returned value, but I am having trouble my click trigger on the delete span tag associated with the link. I am seeing the hash appear in the url indicating a click on the element, but my console.log does not fire, indicating to me that something is off.  Here is my post-image upload jQuery:  $("#file-input").on('change', function(){         var files = $(this).get(0).files;          if (files.length > 0){             var formData = new FormData();              for(var i = 0; i < files.length; i++){                 var file = files[i];                 console.log(files[i]);                 formData.append('fileUpload', file, file.name);             }              $.ajax({                 url: '/app/sign',                 type: 'POST',                 data: formData,                 processData: false,                 contentType: false,                 success: function(data){                     for(var i = 0; i < data.length; i++){                         console.log('This is the element ' + data[i]);                         $('.file-preview').append("" + data[i] + "
");                     }                 },                 error: function(error){                     console.log('error ' + JSON.stringify(error));                 }             });         }         if (files.length > 5){             alert('You can only upload a maximum of five files at this time');             return false;         }     });   With an emphasis on the appended HTML:  $('.file-preview').append("" + data[i] + "
");   On .remove-file click, I'm not seeing the console.log or alert:  $('.remove-file').on('click', function(){     console.log('Delete Triggered');     var fileLink = $(this).data('file-link');     alert(fileLink);     /*alert($(this).attr('href'));     $.ajax({         url: '/app/sign',         type: 'DELETE',         data: fileLink,         success: function(){             $('.file-preview').remove();         },         error: function(error){             console.log('error ' + JSON.stringify(error));         }     })*/ });

I have a bit of code where I am looping through all the select boxes on a page and binding a .hover event to them to do a bit of twiddling with their width on mouse on/off.  This happens on page ready and works just fine.  The problem I have is that any select boxes I add via Ajax or DOM after the initial loop won't have the event bound.  I have found this plugin (), but before I add another 5k to my pages with a plugin, I want to see if anyone knows a way to do this, either with jQuery directly or by another option.


We have to find the integration of the following function  I tried but got stuck can anybody help me how to proceed . Is there anyother method to solve this

The question:      Compute$$ \int \frac {x^2 \, \operatorname{d}\!x} {(x\sin x+\cos x)^2} $$   Tried integration by parts. That didn't work.  How do I proceed?


I am currently learning how to use database in Android. For one of my app, I need to stock 500 string values in order to read them. Actually to fill my database, I read a .txt file at the database creation with all the string values inside. For each lines of .txt (corresponding to a string value), I create a new data in the database. The thing is I know that accessing a file can be long it is not a very good thing if there are thousands of values. According to that, I have two questions :   Is it really usefull to create a database ? (because I can directly access the string values by reading the .txt) Is there a better way to fill the database ? Or a way to create a database already filled before the activity creation ? (because currently, each time you close the activity you close the database and each time you reopen it, it recreate and refill the database.)

If your application requires a database and it comes with built in data, what is the best way to ship that application? Should I:   Precreate the SQLite database and include it in the .apk? Include the SQL commands with the application and have it create the database and insert the data on first use?   The drawbacks I see are:   Possible SQLite version mismatches might cause problems and I currently don't know where the database should go and how to access it. It may take a really long time to create and populate the database on the device.   Any suggestions? Pointers to the documentation regarding any issues would be greatly appreciated.


I am making a mini version of Russian Rullet.  I have a code which gives me a random number from 1 - 36 but I also need to ask my program to randomly give either Red or Black?  from random import randint  print(randint(1,36)) print (randint ('Red', 'Black'))

Assume I have the following list:  foo = ['a', 'b', 'c', 'd', 'e']   What is the simplest way to retrieve an item at random from this list?


Here is what I have as a proof for now. Can you tell me where I need to edit it and or how it should be instead?  Let  and  be two arbitrary binary structures with an isomorphism f: S->T. Assume * is commutative.  Then we have that f(a*b)=f(a)*f(b) for all a, b in S Due to commutativity f(b*a)=f(b)*f(a)=f(a*b) From this we have proven that the operation is preserved.  Since f maps S bijectively to T the function is an isomorphic operation and therefore a structural property

Show that the operation $*$ is commutative is a structural property.   Give a careful proof that the indicated property of a binary structure $\langle S,* \rangle$ is indeed a structural property.  I've started this problem as:  Let $\langle S,* \rangle$ be isomorphic to $\langle T,\Box\rangle$. Also let $f:S \to T$. This means that for $a,b \in S$, then $f(a*b)=f(a)\Box f(b)$ and $f(a*b)=f(b*a)=f(b)\Box f(a)$ and therefore $f(a)\Box f(b)=f(b) \Box f(a)$. This means that an operation $*$ is commutative is a structural property. Does this work?


Example: Cast the sphere then duck around a corner away from the fight and move it on each of your turns as a bonus action while staying safe and keeping concentration. Flaming Sphere (PHB 242-243)  A 5-foot-diameter Sphere of fire appears in an unoccupied space of your choice within range and lasts for the Duration. Any creature that ends its turn within 5 feet of the Sphere must make a Dexterity saving throw. The creature takes 2d6 fire damage on a failed save, or half as much damage on a successful one. As a Bonus Action, you can move the Sphere up to 30 feet. If you ram the Sphere into a creature, that creature must make the saving throw against the sphere's damage, and the Sphere stops moving this turn. When you move the Sphere, you can direct it over barriers up to 5 feet tall and jump it across pits up to 10 feet wide. The Sphere ignites flammable Objects not being worn or carried, and it sheds bright light in a 20-foot radius and dim light for an additional 20 feet. At Higher Levels: When you cast this spell using a spell slot of 3rd Level or higher, the damage increases by 1d6 for each slot level above 2nd.  Do you need to be able to see where you want to move a flaming sphere to?

With spells like Moonbeam or Flaming Sphere, how should we treat the movement of their areas-of-effect when it comes to passing them behind a thick pillar or around a blind corner?  Should we treat any movement of them as if they are being 're-cast' (and so requiring a clear unobstructed view)? Or could a mage presumably will them somewhere out-of-sight?


I was asked on the best and worst case scenario for this function:  def is_palindromic(the_list):      result = True      the_stack=Stack()     for item in the_list:         the_stack.push(item)     for item in the_list:         item_stack=the_stack.pop()         if item != item_stack:             result = False     return result   This function determines if a list is the same as its reverse using a stack. I thought the time complexity was the same for every case but when I tested, it took longer to run if the list was indeed the same as its reverse. Can anyone explain why? I am a bit confused.

Most people with a degree in CS will certainly know what . It helps us to measure how well an algorithm scales.   But I'm curious, how do you calculate or approximate the complexity of your algorithms?


When I joined Programmers SE, I earned 100 points reputation bonus. However, the icon still shows that I only gained +94. Even considering last week's activity, this count is unexplainable. Did I find a bug? It's happened to me a lot, but I finally decided to report it.

Yesterday my answer was accepted, but I got no notification in top bar, moreover, top bar still shows that I earned 45 reps  while reputation tab shows right 60 rep.  Update: July, 11 Again having this problem: In the dropdown:  In the rep tab:  You see, first down votes in the drop down are missing.


I am studying congruence and I am trying to solve this problem, but I cannot think of a way to do this. Would anyone be able to help me? Show that the integers 1111, 111111, 11111111, ... (numbers formed by an even number of numbers 1) are all composed.

We know 11...11 (n times) is a prime number prove n is also prime.  it is easy to understand n is an odd number and 3 does not divide it but I could not do some thing more


The issue is that after I enter 1 exam code it automatically exits the loop. I want to enter more exam scores until i type "exit". But whenever i type the first exam code it goes straight to the system.out.printlns at the bottom. Also, if i have made any other mistakes please let me know. Please help Here is my code: import java.util.Scanner;     public class ExamScoresCalculator{           public static void main(String[] args){              Scanner scan = new Scanner(System.in); // an instance of the scanner class              boolean scoreError = true;       double examScoreLow;       double examScoreHigh;       double examScoreTotal = 0;        int numOfEntries = 0;       int entryScore;              System.out.println( "Enter the lowest possible exam score" ); // user input instructions       examScoreLow = scan.nextInt();              System.out.println( "Enter the highest possible exam score" ); // user input instructions       examScoreHigh = scan.nextInt();                      while(scoreError == true){                    System.out.println("Enter an exam score or type exit"); // asking user to input an exam score          entryScore = scan.nextInt();                     String entryNums = "";          entryNums = Integer.toString(entryScore);                              if(entryNums==( "EXIT") || entryNums==( "Exit") || entryNums==( "exit" )){          scoreError = false;       }else{            entryScore = Integer.parseInt(entryNums); //converting user input into a number                      if(entryScore < examScoreHigh && entryScore > examScoreLow){ //checking in entry is in range             numOfEntries++; // updating number of exam score entries             examScoreTotal = entryScore;             ++examScoreTotal;                if (entryScore < examScoreLow){ // checking if entry is less than highest exam score                 examScoreLow = scan.nextInt();             }             if (entryScore > examScoreLow){               }           }else{             System.out.println( "Not a valid exam score, please try again"); // asking user to input an                                                                                exam score           scan.nextInt();                   }               }//closing first else        }//closing while loop                System.out.println("The total number of exam scores is: " + numOfEntries);        System.out.println("The lowest exam score is: " + examScoreLow);        System.out.println("The highest exam score is : " + examScoreHigh);        System.out.println("The average exam score is : " + examScoreTotal / numOfEntries);                }//closing main method  }//closing classimport java.util.Scanner;

I've been using the == operator in my program to compare all my strings so far. However, I ran into a bug, changed one of them into .equals() instead, and it fixed the bug.  Is == bad? When should it and should it not be used? What's the difference?


I'm trying to make my usb flash drive to a bootable stick. I've downloaded the ubuntu 16.10 iso and whenever I try to make it with startup disk creator this error occure. What should I do?

How do I make an Bootable Ubuntu USB containing the the latest version of Ubuntu?  For completeness, how would I be able to do this on Ubuntu, Windows, OS X or another Linux distro?


I have searched a lot about it but could not get an answer. I read somewhere that linux Ubuntu has 6 or 7 terminals.   We can start them by pressing -  Ctrl+Alt+(F1-F6)   and to get back to GUI-  Ctrl+Alt+F7   So what i want to know is what is the difference between these 6 different terminals , and how can we use them as per to different purposes??

What is the reason for having so many virtual consoles?  I would understand if there was one in case the GUI crashes but 6 more besides the default? What are they for? I even see no usage for any of them except when the GUI freezes.


I'm trying to create a custom property and do some work as the property is set.  I previously used the update function; which worked great, except it never got called on updates resulting from drivers or the animation system.  set does appear to get called in all cases, but I can't figure out how to store to the underlying property. I obviously can't store to is directly as I get an infinite loop and the answers I've found on the internet are wrong e.g. they suggest you can just store it using a dictionary indexing and it will set the property - but that doesn't work. >>> def cb(self, value): ...     print(self, value) ...     self['param'] = value ... >>> bpy.types.Object.param = bpy.props.FloatProperty(set=cb) >>> bpy.context.scene.objects['Cube'] bpy.data.objects['Cube']  >>> bpy.context.scene.objects['Cube'].param 0.0  >>> bpy.context.scene.objects['Cube'].param = 1.0 <bpy_struct, Object("Cube")> 1.0  >>> bpy.context.scene.objects['Cube'].param  # I want this to reflect the new value 0.0  >>> bpy.context.scene.objects['Cube']['param']  # I don't want this to exist 1.0

Here is my test code and picture:  import bpy   # Simple property reading/writing from ID properties. # This is what the RNA would do internally. def get_float(self):     return self["testprop"]   def set_float(self, value):     self["testprop"] = value  #bpy.types.Scene.test_float = bpy.props.FloatProperty(get=get_float,set=set_float) bpy.types.Scene.test_float = bpy.props.FloatProperty()   bpy.context.scene.test_float = 12.34     When I don't explicitly set the "get/set" function for my property, after assigning the value, I can get the property value by 'scene["test_float"]', but if I explicitly set the "get/set" function, then if I try to type in the same commands, I will receive a error "KeyError: 'bpy_struct[key]: key "test_float" not found'" . So what should I do to get the same results by using explicitly  "get/set" function?


Is it "They are  friends of my son and I" or is it  "They are friends of my son and me" or is it this which I think correct "They are friends of mine and my son"?

As  shows, we nearly always use the possessive form of personal pronouns for friend of mine/his/ours/etc.  But when it comes to actual names, we prefer  without the possessive apostrophe. That preference is even more marked with, say, . Not that I think the usage itself is particularly American - it's much the same with .  Personally, I find friend of him grates. In general I've no strong feelings either way as to whether it's friend of Peter or friend of Peter's (though I deplore the possessive in ), but in line with many others, I really don't like the possessive in relation to things like countries.  Why is this?   Edit: Noting an apparent "progression" (pronoun -> person -> nation) marked by reduction in use of the possessive, I checked at a finer "granularity". NGram shows that although it does occur,  virtually "flatlines" against friend of mine. But the bias reduces through of you, of us, and by the time I get to  it's much less extreme. There seems to be something "egocentric" about the double possessive.  Presumably when babies learn to speak, they soon notice that possessive pronouns, possessive apostrophes, and the word "of", all do the same job. Parents would correct a child who says "of mine's", but probably wouldn't even notice the same "redundancy" in "of Peter's". Younger speakers are unlikely to even be talking about something "of America's". Perhaps as we mature we tend to discard the "double possessive" for the more "distant" things that only adults are likely talk about, but we keep it for "closer" people because that's how we spoke when we were younger.  EDIT2 I note that I'm a great fan of him is vanishingly rare compared to ...fan of his, but with ...fan (of John) the double possessive occurs far less often than ...friend (of John's). Usage seems to be affected by the noun before "of" as well as the one after it. This is getting complicated...


I am using the algorithm2e package for a paper, and I am using it as follows:  \usepackage[ruled,linesnumbered]{algorithm2e}   Everything works OK, however, when I added the linesnumbered directive (not sure how is that called in latex) to the package declaration, I noticed that the algorithm gets out of the margin of the rest of text.  The following image shows the issue, you can see that after line #9, it should be #10, however, you can only see #0, because the 1 got covered by the green line.    Is there a way to force the algorithm to move a bit to the right?  I am using: Texstudio under linux  Update: Marked as duplicated with  question, but I think is not, that question is about the position of line numbers within the algorithm box itself, while this question is about the whole content of the algorithm box, with respect to the rest of the text (regular, not part of the algorithm)

When using line numbers in the algorithm2e package, the line numbers are placed left of the text block, not directly below the text. See page 5 of the .  Is it possible to place them below the text ?  Update: Line numbering now:     Input ...    Output ... 1: Code ...   Line numbering I want:  Input ... Output ... 1: Code ...


In my MVC3 application there are a couple of situations where I a display a splash screen dynamically load a partial view via jQuery's ajax methods and injecting html into the DOM.  The thing is if authentication expires and then a user initiates an ajax call, the action being called redirects to the log in page, so the html for the log in page is returned and is injected into the DOM, which is obviously going to be extremely confusing for the user.  How do people normally deal with this situation? I imagine it is common as forms auth and ajax requests for html are something that I do a lot.

I'm using $.post() to call a servlet using Ajax and then using the resulting HTML fragment to replace a div element in the user's current page. However, if the session times out, the server sends a redirect directive to send the user to the login page. In this case, jQuery is replacing the div element with the contents of the login page, forcing the user's eyes to witness a rare scene indeed.   How can I manage a redirect directive from an Ajax call with jQuery 1.2.6?


What's the difference between "I..." and "I have..."? For example, what would be the difference between saying "I recently moved back to Portland" and "I've recently moved back to Portland"?

A student has written:     Still, I have already been aware of most of the information even    before watching the video.   It doesn't feel right and I would normally use a past simple here. I'm on my two hundredth script and losing my ability to reason, or to adequately explain to myself why it should be past simple (I think it's 'before' as this puts the time as completed, so he can't use the present perfect notion of unfinished time). What I need to know is:   Should it be simple past of present perfect here, or doesn't it matter?  Why/why not?   All help gratefully received.


I would like to change some specific icons in the launcher but no matter what I try I cannot solve this issue if someone could possibly supply  step by step I would be grateful.

I'm trying to change the icon of a specific application (Pidgin) in my Ubuntu 11.10 Unity launcher. I have tried searching in the options and in the Compiz settings but could locate no option for changing individual icons.  I can change the theme but that's not what I want.   I am willing to edit configuration files to get this change. It doesn't have to be a UI solution.


I'm trying to create an interactive shell from an existing application that interprets command line arguments like this:  application.exe command subcommand someNumber=1 boolArgument s="string argument with spaces"   When entering the Main, I receive an string array that contains all the arguments provided, and this already treats s="string argument with spaces" as one block. I'd like to handle an interactive Console input the same way, but wasn't able to find an equivalent function...   Do I really have to parse it myself? My straight forward approach would be to read the whole line and splitting at spaces, but then I'd have to handle the case for string arguments in quotes...  EDIT:  Maybe some clarification: I'm searching for out-of-the-box string argument parser that respects string literals in quotes, such that I receive the same results as when using the same input as command line arguments. Yes, I can split it myself, e.g. using RegEx, but I was wondering if there isn't something I can use, since I receive the command line arguments that way.

I have a single string that contains the command-line parameters to be passed to another executable and I need to extract the string[] containing the individual parameters in the same way that C# would if the commands had been specified on the command-line. The string[] will be used when executing another assemblies entry-point via reflection.  Is there a standard function for this? Or is there a preferred method (regex?) for splitting the parameters correctly? It must handle '"' delimited strings that may contain spaces correctly, so I can't just split on ' '.  Example string:  string parameterString = @"/src:""C:\tmp\Some Folder\Sub Folder"" /users:""abcdefg@hijkl.com"" tasks:""SomeTask,Some Other Task"" -someParam foo";   Example result:  string[] parameterArray = new string[] {    @"/src:C:\tmp\Some Folder\Sub Folder",   @"/users:abcdefg@hijkl.com",   @"tasks:SomeTask,Some Other Task",   @"-someParam",   @"foo" };   I do not need a command-line parsing library, just a way to get the String[] that should be generated.  Update: I had to change the expected result to match what is actually generated by C# (removed the extra "'s in the split strings)


Suppose that $f(z)$ is entire with $a$ and $b$ positive constants. If $$f(z+a)=f(z+b i)=f(z)$$ for all $z$, show that $f(z)$ is constant . Which theorem could I use ? Please give some hint thankyou

Let $f: \Bbb C \to \Bbb C$ be an entire (analytic on the whole plane) function such that exists $\omega_1,\omega_2 \in \mathbb{S}^1$, linearly independent over $\Bbb R$ such that: $$f(z+\omega_1)=f(z)=f(z+\omega_2), \quad \forall\,z\in \Bbb C.$$Prove that $f$ is constant.   The intuition seems clear to me, we have the three vertices of a triangle given by $0$, $\omega_1$ and $\omega_2$. All points in the plane are one of the vertices of that triangle under a suitable parallel translation. The constant value will be $f(0)$, fine. Throwing values for $z$ there, I have found that $$f(n\omega_1) = f(\omega_1) = f(0)=f(\omega_2) = f(n\omega_2), \quad \forall\, n \in \Bbb Z.$$  I don't know how to improve the above for, say, rationals (at least). Some another ideas would be:   Checking that $f' \equiv 0$. I don't have a clue of how to do that. Write $w = a\omega_1+b\omega_2$, with $a,b \in \Bbb R$, do stuff and conclude that $f(w) = f(0)$. This approach doesn't seem good, because I only have a weak result with integers above. Finding that $f$ coincides with $f(0)$ on a set with an accumulation point. This seems also bad: the set on with $f$ coincides with $f(0)$ by which I found above is discrete.    Nothing works and this is getting annoying... And I don't see how analyticity comes in there. I'll be very thankful if someone can give me an idea.  (On a side note.. I know that this title is not informative at all. Feel free to edit if you come up with something better.)


I installed Ubuntu on windows 7 using wubi software, now i want to practice c,c++ and java programming. As I am new to Ubuntu, I don't know how to get those compilers. I saw so many comments on google search. there they mentioned commands sudo apt-get install build essential, but i don't have cd - I installed ubuntu through wubi. So can you please guide me how to get those.  Kind Regards Munisekhar

I shifted to Ubuntu 10.10 now I am facing problem to have C/C++ compiler. What are the possible ways so that I can use C/C++ compiler using all the libraries (like graphic, math, conio, stdlib, etc) as in Microsoft Windows creating executable file?


I am trying to use this  as a simple constant voltage source to power a compact adjustable DC-DC converter.   www.amazon.com/Charger-RAVPower-Adapter-Compatible-MacBook/dp/B07PLR7T1M  I want the high power density that these new GaN transistor converters have, but the only ones I've found have only a USB-like output rather than a simple constant voltage that I want to power my DC-DC converter. Is there a way to make this AC adaptor output just a constant 20V?  I have tried to research how the PD 3.0 system decides what voltage and current limit to supply, but I have not understood an explanation for what I want since it is not what the USB PD system was designed for. I am thinking the solution would involve connecting certain value resistors to certain pins in the connector to signal the adaptor to output a constant voltage. Can any USB experts help me?

I want to power my DIY stuff with a MacBook Pro USB C charger. The label on a charger says that it can provide three different power profiles:    20.2V - 4.3A 9V - 3A 5.2V - 2.4A   There is a ton of information about what USB-C power distribution is capable of, but I can't find any examples of how exactly to do it.   Is there an easy way or workaround to request one of those power profiles without using a microcontroller?  For example, I got apple MacBook Pro charger, apple USB-C cable, and a breakout board like this one:


How would you go about writing an expression for:  "The number of subsets of $\{1,2,3, . . . ,10\}$ with three elements, that contain at least one odd number and at least one even number."  I can work out an expression for each of these, but I am not sure how to write an expression that combines all three conditions ($3$ elements, at least one odd & even) - there would be less subsets for an expression when conditions are combined.  Appreciate any help.

Find the number of three element subsets $A$ of $\{1,2,...,10\}$ such that $A$ contains at least one even and one odd integer.  I think in this way: First we distribute one even and one odd number to 3 sets.Then there are 4 digits left of which 2 are even and 2 are odd.But how to distribute this 4 digits into 3 sets?


I Thought that deleting the partition with Ubuntu on it, it would uninstall it I know now that it doesn't. But now I cant open windows because all I get when I boot is the grub rescue screen I don't know how to boot from a USB (Where I downloaded Ubuntu From) and I don't have the disk to install windows 7 because it came with the PC anything will help. Thank You in advance. I'll be able to give feedback on weekdays.

I have absolutely no experience with Linux, and I desperately need to get my computer back up and running again with Windows.  How do I remove Ubuntu and reinstall Windows?    Editor's note: many of the answers are about removing Ubuntu from dual-boot but keeping Windows (which is a bit complicated), while other answers are about removing Ubuntu from single-boot (which is easy: basically just format the disk while installing Windows). The question as written is ambiguous between dual-boot or single-boot.


I am following the the book "Lecture notes on functional analysis". The following extension thm has been proven in the book.   If we consider the finite dimensional case of the $X$, does the following prove work for the existence of the linear functional $F$? $\to$ My guess is yes but I have some problem of proving the property $\|F\|=\|f\|$.  Let $\{x_1,\dots, x_k\}$ be basis for $V$. We can extend it to a basis  $\{x_1,\dots, x_k,x_{k+1},\dots , x_n\}$ of $X$ and set $F(x_m)=0$ for $m = k+1, \dots , n$. So for any $X\ni x = a_1x_1+\dots+a_nx_n$ , we can define $F(x)=a_1f(x_1)+\dots+a_kf(x_k)$. Then $F$ is a linear functional on $X$, $F(x)=f(x) , \forall x\in V$, and $\|F\|=\|f\|$.

Hahn Banach Theorem states that given a linear continuous functional $f$ on a subspace $N$ of a normed space $M$, it can be extended to a linear functional $F$ on the whole space $M$ and the norm of the extension is the same as the one of $f$.  Can someone tell me if something is wrong in the following lines:   Fact 1: Every vector space has a basis (use axiom of choice if it is infinite dimensional). Fact 2: A linear map is defined if we give the image of a basis.  Take $\{e_i\}_{i\in I}$ a basis of $M$ extending one of $N$, and define $F(e_i):=f(e_i)$ if $e_i$ is in $N$ and $0$ otherwise. This is clearly an extension of $f$, plus the norm of $F$ is the same as that of $f$ because sup $|F(x)|/||x||$ is $0$ for $x \in M \setminus N$ and $||f||$ if $x \in N$.   In case is correct this seems like a very simple proof of this theorem!


Ive created a custom shortcode via functions.php to display a phone number in the content when the shortcode is used in the WYSIWYG field.  function contact() {   $contact = get_field('contact',options);   echo $contact; } add_shortcode('contact', 'contact');   However in the content editor when we write "contact us on [contact]" it comes out on the front end with the phone number first and then contact us on on the next line.  I've also tried this:  function contact() {   $contact = get_field('contact',options);   printf ('%s',$contact); } add_shortcode('contact', 'contact');   How can I please get this string to be included in the paragraph and not be on its own line above any content?  Thanks, Adrian

I'm trying to create a shortcode base on the following code:

Filter:

<a href="<?php echo get_permalink( 23 ); ?>">All
     <?php global $post; $thispage = $post->ID; // grabs the current post id from global and then assigns it to thispage ?>     <?php $pagekids = get_pages("child_of=".$thispage."&sort_column=menu_order"); // gets a list of page that are sub pages of the current page and assigns then to pagekids ?>      <?php if ($pagekids) { // if there are any values stored in pagekids and therefore the current page has subpages ?>
             <?php wp_list_pages("depth=1&title_li=&sort_column=menu_order&child_of=".$thispage); // display the sub pages of the current page only ?>
             <?php } elseif($post->post_parent)                $children = wp_list_pages("title_li=&child_of=".$post->post_parent."&echo=0"); if ($children) { // if there are no sub pages for the current page ?>
             <?php echo $children; ?>
             <?php } ?>
   Out of the question, this is a really good resource since it returns the child pages and even brother's pages.  ok back to the game.... I trying to create a short code based on this, however if not working, so far I have this:  function filter_store ( $atts ) { global $post; $thispage = $post->ID; if ($pagekids) {    $output .= '
';       wp_list_pages("depth=1&title_li=&sort_column=menu_order&child_of=".$thispage);        $output .= '
';                } elseif($post->post_parent)             $children = wp_list_pages("title_li=&child_of=".$post->post_parent."&echo=0"); if ($children) {        $output .= '
';             echo $children;        $output .= '
';             }         return $output;     }     add_shortcode('filter', 'filter_store');   I have spent around 3 hours trying to find where the error is, and my head is about to explode, I would appreciate any kind of help on this.  Thank in advance.


I have been working on this report and I saved and downloaded certain images off the internet to put in my paper. When I was going back to cite them later, I reverse google searched the images by uploading the images to have the search engine find them on the internet. Some of these images could no longer be found. How do I cite the images I can no longer find the sources for? Or should I just find different images?

My colleague is writing a manuscript about a subject that is rarely reported in the mainstream literature (predation events). A few years ago on a fishing forum she found a photograph that demonstrated this phenomenon pretty well and saved it to her computer, but unfortunately between then and now the original source has vanished: Google Reverse Image Search can't locate it, the website is no longer running and is also unavailable in the Internet Archive. The original URL to the photo was also not retained.  What's the proper way to cite this source? It's not critical to include but it would definitely improve the final manuscript.


When I open a a Stock 3D model I downloaded, the entire interface changes. I see a "Default" layout option, but I don't see the stand "Layout" option at top of page. Is it possible that the model I have was created pre 2.8 & needs to be converted?  The model also does not have a Camera, & I can't see to find the "Add Camera" option that I see in basic tutorials.  I have attached screenshot of the UI as it appears with my stock model. Total Noob thanks you

I cannot find any menu or keys that return blender to the view that you see when you start blender. Using save close and then open again but it must be easier than that?  How do you change the view from side or front, or back to the view that is enabled by default at start?


Help, i'm trying to make resolution like in Terraria on PC, when it is fullscreen but still windowed. Why this code won't work?  package com.imaginegames.mmgame.desktop;  import com.badlogic.gdx.Gdx; import com.badlogic.gdx.backends.lwjgl.LwjglApplication; import com.badlogic.gdx.backends.lwjgl.LwjglApplicationConfiguration; import com.imaginegames.mmgame.GameMain;  public class DesktopLauncher {     public static void main (String[] arg) {         LwjglApplicationConfiguration config = new LwjglApplicationConfiguration();         config.foregroundFPS = 60;         config.title = "Millitary Madness";         config.width = Gdx.graphics.getWidth();         config.height = Gdx.graphics.getHeight();         new LwjglApplication(new GameMain(), config);     } }     It says:  Exception in thread "main" java.lang.NullPointerException     at com.imaginegames.mmgame.desktop.DesktopLauncher.main(DesktopLauncher.java:13)

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?


Which LaTeX compiler supports best writing a thesis? Which one provides the best compatibility with commonly used classes and packages?  The compilers that I frequently use are:   latex pdflatex   Examples of classes I use to write a thesis are:   memoir report scrrprt   The packages I most frequently used are:   environ, etoolbox, calc geometry, changepage amsmath, amsthm, amssymb, bbm, mathtools colorx longtable, multicol graphicx, graphics, placeins, grffile, epstopdf, psfrag wrapfig tikz, pstricks, pgfplots pdfpages siunits glossaries hyperref

I am confused about what TeX and its offspring (LaTeX, pdfTeX/pdfLaTeX, e-TeX, ConTeXt, LuaTeX, etc.) are.  Some, like LaTeX, seem like add ons to TeX (maybe a change to the eyes and mouth, but not stomach). Others, like pdfTeX, seem like changes to the underlying system (i.e., a change to the stomach).  Is there a good reference that explains the differences and the evolution?


Is there a way to run Unity alongside KDE? I have installed Kubuntu/KDE and I am wondering if I can install Unity so I can switch back and forth between the two.

I have been running Kubuntu 15.10 32-bit for a while, and although I love the KDE enviroment, I would like the option of having Unity. So, I did the following:  sudo apt-get update sudo apt-get install unity   I then rebooted, and when I was at the login screen, I tried to switch from plasma to unity, but the only options were "Plasma" and "Failsafe". When i run:  sudo apt list | grep gnome   or:  sudo apt list | grep unity   I am presented with several packages saying "Unity-8-desktop", or something along those lines, so I know Unity is installed, I just can't reach it. Can anyone help me?


Just looking for some hints on how to create the effect as shown in the attached image.

Here's an image of a cube with lots of edges added. It was created using knife tool and lots of clicking:    What would be the best way to randomly generate such cuts with less effort...?


Question on Gravity and the old "all objects free fall at the same rate regardless of their mass"  I "drop" three objects,  one at a time, towards the earth   First object has less mass than the earth  Second object has  mass equal to the earth   Third object has greater mass than the earth    in all cases as Gravity "pulls" the two together. The greater mass object wins this simple "tug of war" due to inertia and is moved relatively less. The lighter mass object moves relatively more. You could plot a curve (heavier moves less) with the object of equal mass at center.  So what am I missing in the semantics of "all objects free fall at the same rate regardless of their mass" is popularly taught and I think the average person understands they are being told?

The common understanding is that, setting air resistance aside, all objects dropped to Earth fall at the same rate. This is often demonstrated through the thought experiment of cutting a large object in half. The halves clearly can't then fall more slowly just by being sliced in two.  However, I believe the answer is that when two objects fall together, attached or not, they do "fall" faster than an object of less mass alone does. This is because not only does the Earth accelerate the objects toward itself but the objects also accelerate the Earth toward themselves. Considering the formula: $$ F_{\text{g}} = \frac{G m_1 m_2}{d^2} $$  Given $F = ma$ thus $a = F/m$, we note that the mass of the small object doesn't seem to matter as when calculating acceleration the force is divided by the $m$ term, its mass. However, this overlooks that the force is actually applied to both objects, not just to the smaller one. The acceleration on the second, larger object is found by dividing $F$, in turn, by the larger object's mass. The two objects' acceleration vectors are exactly opposite, so closing acceleration is the sum of the two:  $$ a_{\text{closing}} = \frac{F}{m_1} + \frac{F}{m_2} $$  Since the Earth is extremely massive compared to everyday objects, the acceleration imparted on the object by the Earth will radically dominate the equation. As the Earth is $\sim 5.972 \times {10}^{24} \, \mathrm{kg} ,$ a falling object of $5.972 \, \mathrm{kg}$ (just over 13 pounds) would accelerate the Earth about $\frac{1}{{10}^{24}}$ as much, which is one part in a trillion trillion.  Of course in everyday situations, we can for all practical purposes treat objects as falling at the same rate because of this negligible difference—which our instruments probably couldn't even detect. But I'm hoping not for a discussion of practicality or what's measurable or observable, but what we think is actually happening.  Am I right or wrong?  What really clinched this for me was considering dropping a small Moon-massed object close to the Earth and a small Earth-massed object close to the Moon. This made me realize that falling isn't one object moving toward some fixed frame of reference, but that the Earth is just another object, and thus "falling" consists of multiple objects mutually attracting in space.


Using completing the square method we can derive a formula $ax^2+bx+c=0$ for the quadratic equation to $$x={-b\pm \sqrt{b^2-4ac}\over 2a}$$  I am sure I haven't sees it in any book talking about deriving the cubic equation $ax^3+bx^2+cx+d=0$ using the method of completing the square or the cube.  So how did they derive the cubic formula to solve the cubic equation?

Overview I have tried finding a solution to this problem myself and I have flailed. Its just a challenge for me. could you please tell me how far am I in solving this question? My approach for quadratic equation : I am still a student, and when I first saw the quadratic formula I wanted to derive it myself and I did it. This was my logic: the equation $x^2 + bx + c=0$ is obviously supposed to contain 2 roots (real or imaginary). So any 2 points in an axes can be represented as: $n+k$ or $n-k$. so (1) : putting $x = n+k$, (2): putting $x=n-k$ we get two equations; on subtracting $(1) - (2)$ we get an equation in $n$ and $k$ as, $4nk+2kb=0$ which gives $n=-b/2$.  Now substituting this value of $n$ in $(1)$ and $(2)$ and adding them we get $k= (+or-) \sqrt{b^2 -4c}/2 $. My approaches for trying to solve cubic equations: Let $x^3+bx^2+cx+d = 0$ be the equation. My first trials were focused on extracting the roots by various substations. Let me explain some of them. Originally, when I derived the quadratic equation, I wanted to literary "represent the solution" by $n+k$ and $n-k$. most methods that I have thought of for cubic equation similar to that of the quadratic (like assigning 3 unambiguous  variables to uniquely represent 3 roots- $n$ and $k$ represents unique values), by considering 3 unique values, but they end up being ambiguous. Then I was suddenly struck with the idea that I could define certain random operators to "transform" the equation in some way changing the co-coefficients of $x^2, x, x^0$. I have defined the first transformation as: $x^3+bx^2+cx+d=0 \to x^3+ b'x^2 + c'x+d' =0   $ then $b' = b$, $c' =b^2+c$, $d' = bc-d$. Applying this operation changes the modified equation's zeros as follows: $\alpha'=(\alpha+\beta)/2, \beta' = (\beta+\gamma)/2, \gamma' = (\alpha+\gamma)/2 $ if the initial zeros are $\alpha, \beta, \gamma$. My latest assumption is that creating $n$ number of transformations and applying them can help us obtain the roots in some combination. The other operation I have defined is "increment roots by by $\theta$ operation". in this case, $x^3+ bx^2+ cx+ d \to x^3+b'x^2+ c'x+d=0$. here, $b' = b + 3\theta, c' = 3\theta^2+ 2\theta b+ c, d' = \theta^3 +b\theta^2 + c\theta + d$. This modification transforms the original roots $\alpha, \beta, \gamma$ to $\alpha' = \alpha + \theta, \beta' = \beta + \theta, \gamma' = \gamma + \theta$ Now for my questions: How far am I from solving the cubic polynomial problem myself without any external help? More over, I give up. How to find the roots of a cubic equation? Could my latest idea for solving cubic equations actually be applied (the transformation method)? Is it possible to find the roots with my transformation method? (my second transformation definition was successful in converting the coefficient b or c to zero by transforming the roots linearly)


What I don't get is,  I know that auto property is suppose to make things easier.   Normally:  private string name;  public string Name {     get { return name; }     set { name = value; } }   With Auto Property:  public string Name { get; set; }   But if we can just declare the instance variables as public, like in the auto property, why don't we declare instance variable in the normal version as public as well?  So would this be exactly the same as the previous ones? :  public string name;  public string Name {     get { return name; }     set { name = value; } }

In C#, what makes a field different from a property, and when should a field be used instead of a property?


Since the Earth is revolving around the Sun, therefore it is accelerating.  This implies that any stationary charge on earth is also accelerating. However, I have never heard anyone saying anything about that. Why is this so? Do charges on Earth not emit electromagnetic radiations?

The  gives the recoil force, $\mathbf{F_{rad}}$, back on a charged particle $q$ when it emits electromagnetic radiation. It is given by:  $$\mathbf{F_{rad}} = \frac{q^2}{6\pi \epsilon_0 c^3}\mathbf{\dot{a}},$$  where $\mathbf{\dot{a}}$ is the rate of change of acceleration.  If a particle has a constant acceleration, $\mathbf{\dot{a}}=0$, then there is no reaction force acting on it. Therefore the particle does not lose energy.   Does this mean that a constantly accelerating charged particle does not emit electromagnetic radiation?


I am learning now how to make my program distinguish two types of input in one function... I know its possible but how can I actually do it ;-; Heres abit of my code:  def alphanumeric_input_detection(base_input):     if (type(base_input)==str):         return (print("you've written it wrong you dumm dumm"))     else:         return(print("thats correct input"))  base_input=input("please write a number")  alphanumeric_input_detection(base_input)

What is the best possible way to check if a string can be represented as a number in Python?   The function I currently have right now is:  def is_number(s):     try:         float(s)         return True     except ValueError:         return False   Which, not only is ugly and slow, seems clunky. However I haven't found a better method because calling float in the main function is even worse.


In the twin paradox from what I understand both observer see each other's time dilated so they always believe that the other frame is younger. Finally because the space ship frame has to make many accelerations it results that he will be younger. However, what if the frame in the space ship doesn't have to make any accelerations to come back to earth and could simply just come back like if the space was a looped or that there was a wormhole , so in this case who would be younger ?

Take the following gedankenexperiment in which two astronauts meet each other again and again in a perfectly symmetrical setting - a hyperspherical (3-manifold) universe in which the 3 dimensions are curved into the 4. dimension so that they can travel without acceleration in straight opposite directions and yet meet each other time after time.  On the one hand this situation is perfectly symmetrical - even in terms of homotopy and winding number. On the other hand the Lorentz invariance should break down according to , so that one frame is preferred - but which one?  So the question is: Who will be older? And why?  And even if there is one prefered inertial frame - the frame of the other astronaut should be identical with respect to all relevant parameters so that both get older at the same rate. Which again seems to be a violation of SRT in which the other twin seems to be getting older faster/slower...  How should one find out what the preferred frame is when everything is symmetrical - even in terms of GRT?  And if we are back to a situation with a preferred frame: what is the difference to the classical Galilean transform? Don't we get all the problems back that seemed to be solved by RT - e.g. the speed limit of light, because if there was a preferred frame you should be allowed to classically add velocities and therefore also get speeds bigger than c ?!? (I know  is only a local theory but I don't understand why the global preferred frame should not 'override' the local one).  Could anyone please enlighten me (please in a not too technical way because otherwise I wouldn't understand!)  EDIT Because there are still things that are unclear to me I posted a follow-up question:


hi i started to use math mode for lab reports but when i use the babel package (\usepackage[spanish]{babel}) the dots changes by comma, i been tried to use \DeclareMathSymbol and \mathcode.="8000` options but the bug persist. Can anyone help me?

I'm using Babel for writing a document in spanish.  However, it uses a comma instead of a period as a decimal marker (i.e. 3,14 instead of 3.14).  Is there any way to reverse the behaviour? I prefer the period, as it's done in english.   Also, I'd prefer it if it's something that can just be added to the preamble, instead of having to do it each time I want to write a number with a decimal part (like putting the period between brackets, for instance).


We have quantum computers and we also have Shor's algorithm. So:    Why isn't RSA cracked yet?  What are the current quantum computers lacking?

D-wave systems has released . This means in theory, that all asymmetric encryption algorithms — such as RSA — are now useless due to the speed at which quantum computers can factor.  Has RSA been cracked yet? If not, why hasn't it?  The reason for our company's concern is an upcoming product that relies heavily on cryptography, and a significantly large number of hackers may attempt to break it. If the code was found to be insecure, it would be a huge problem for our company, our users, and anyone on the Internet if RSA was found to be insecure.   Update: article on D-Wave recent announcement


I have a long expression, its' not fitting in my screen, I want to write in several lines.  new_matrix[row][element] =  old_matrix[top_i][top_j]+old_matrix[index_i][element]+old_matrix[row][index_j]+old_matrix[row][index_j]   Python gives me 'indent' error if I just break line.  Is there way to 'fit' long expression in screen?

I have a long line of code that I want to break up among multiple lines. What do I use and what is the syntax?  For example, adding a bunch of strings,  e = 'a' + 'b' + 'c' + 'd'   and have it in two lines like this:  e = 'a' + 'b' +     'c' + 'd'


Imagine I only know a part of the name of the folder(s) or file(s), but don’t know their location(s) in the computer. I even don’t know whether they are hidden or not. How can I search and list them all?  (Say, for example I want to list all the folders and files which are having mysql as the part of their name)

Within a set of directories, how do I find a file whose name includes a given string, such as "abcde"?


I'm gonna conclude that a tautology always a valid argument.  In one hand, by the definition of validity, the conclusion must be true if all of the statements in the argument are true.  On the other hand, an argument is tautology when it's always true, regardless the truth or falseness of its promises.  As an instance x=x is tautology, then it's valid, too.  Am I right by above argument?

Given this definition:     A deduction is valid if and only if its conclusion is true whenever all of its hypotheses are true.   Can an argument be valid if it has a tautology as a conclusion?  An example I can think of is:        A proposition is either a tautology or not a tautology   (1) is a proposition   (1) is either a tautology or not a tautology      That seems strange/wrong to me, even though it appears to meet the definition. Are there other conditions for an argument to be valid?


I have this code:  while (length < content.length()) {         tok += chars.get(length);         tok = tok.toLowerCase();         if (chars.get(length) == ' ') tok = "";         else if (tok == "print") System.out.println("FOUND PRINT!");         System.out.println(tok);         length++;     }   What I'm trying to do is to create a programming language with this. But when I try to detect if (tok == "print") it doesn't detect it. I used an ArrayList to store all chars from a string to that array, and then use a while loop to loop the string's length which you can see in the code. Then I add every char from the array list to the string and when I try detecting if the string is something it won't work.  Output of this code:  [P, R, I, N, T,  , ", H, E, L, L, O, "] p  pr  pri  prin print - I'm trying to detect this  " "h "he "hel "hell "hello "hello"

I've been using the == operator in my program to compare all my strings so far. However, I ran into a bug, changed one of them into .equals() instead, and it fixed the bug.  Is == bad? When should it and should it not be used? What's the difference?


I am reading an excel file:   For now, all I want to do is print to the console each entry in this excel file in the format of: zip code - city - state. For now, all I am trying to do is get zip codes. Here is my approach:          FileInputStream inputStream = new FileInputStream("C:/Users/student/eclipse-workspace/Weather2/bin/resources/uszips.xlsx");         Workbook workbook = new XSSFWorkbook(inputStream);         Sheet firstSheet = workbook.getSheetAt(0);         Iterator<Row> iterator = firstSheet.iterator();         int i = 0;         while(iterator.hasNext()) {             Row nextRow = iterator.next();             if(nextRow.getCell(i+1).getCellType().equals("NUMERIC") && nextRow.getCell(i).toString().length()==5) //this if statement is where the error occurs {                 System.out.println(nextRow.getCell(i).getNumericCellValue());             }             Iterator<Cell> cellIterator = nextRow.cellIterator();             while(cellIterator.hasNext()) {                 Cell cell = cellIterator.next();             }             i++;         }         workbook.close();         inputStream.close();     } }   I get the following error when I run this method:      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 com.sun.javafx.application.LauncherImpl.launchApplicationWithArgs(LauncherImpl.java:389)     at com.sun.javafx.application.LauncherImpl.launchApplication(LauncherImpl.java:328)     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 sun.launcher.LauncherHelper$FXHelper.main(Unknown Source) Caused by: java.lang.NullPointerException     at Forecast.search_Zipcodes(Weather2.java:41)     at Weather2.main(Weather2.java:94)     ... 11 more Exception running application Weather2   I don't understand why I receive a null pointer exception. I know for sure that a value for the cell exists, or is the null pointer exception for something else? Any help would be appreciated, thanks.

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?


I'm confused in whether to write know or knows in the following statement:- "The ones who are included know better."?  Also explain the difference between the two, thanks.

I am getting confused with usage of 's' with verb- consider following 2 sentences-        I am the one who wants to stay with you.   I am the one who want to stay with you.      According to me, first one is the correct usage, because, "the one who" is third person, and hence, the verb will get an 's'. Would like to know what is the rule to be followed in such cases.


I'm a casual Marvel Cinematic Universe (MCU) film fan and have probably watched about a third of the MCU films that came out since .  Is there a "" of MCU films I should watch (or have watched) prior to watching Avengers: Endgame?  I know Avengers: Endgame has not yet come out, but I'm hoping that by the time it's released (April 26, 2019 here in the US), I'll have caught up with those movies I've missed to ensure I'm minimizing any plot holes due to missing a prior film.  Side Note: If this question belongs on a different SE site (such as ), please feel free to migrate it on my behalf.

I have watched all parts of the Avengers (including Civil War) and Hulk series. I am planning to watch rest of the movies of MCU.  I intend to get a fine experience of Marvel movies and most importantly correct understanding of the complete* storyline. For that purpose, is there any particular order in which one should watch the movies of MCU?   It would great if you can justify the order you suggest.  (*I know "complete" is nearly impossible if you are not reading the comics but still)


This question:       Is a great question and has 71 up-votes to boot, but has unfortunately been marked with the wrong answer.  The correct answer quite rightly has 60 up-votes, to the marked answer's 11.  Why can't the community over-rule the person who asked the question in cases like this?

The accepted answer is factually incorrect; one can simply call  row.Table.Columns.Contains(name);   What should be done?


I'm a level 173 Nord. I checked each city and town yet I haven't been able to fight the Ebony Warrior. I have all the DLC that exist for for this game yet no matter where I go, I can't find him.  I've even checked Raven Rock, Tel Mithryn, and Skaal village but there is no sign of him. I've fought quite a lot of legendary dragons and I know that they appear when the Ebony Warrior decides to challenge you.  If you could me that would be great cause I've been itching for a good fight in an long time. I'm on Xbox 360.  Plus when I go on random rampages as a vampire lord I never see the ebony warrior anywhere just a ton of guards and a few townsfolk. (I go on rampages cause I can't find him)

How do I find the Ebony Warrior in Skyrim? I have been searching for him for ages, and a friend of mine said he met him at level 20 on the Skyrim Legendary Edition.  I still don't know where he is, and my friend said he normally finds him in Windhelm. Is this true, or is he a random occurrence?  I'm playing on the Xbox 360.


Error:     java.lang.NullPointerException: Attempt to invoke virtual method 'void android.support.v4.view.ViewPager.setCurrentItem(int)' on a null object reference                                                                         at com.example.iswipe.MainActivity.onRestoreInstanceState(MainActivity.java:68)   public class MainActivity extends AppCompatActivity { TabLayout tabLayout; ViewPager viewPager; FragmentPagerAdapter adapterViewPager;  public static String POSITION = "POSITION";  @Override protected void onCreate(Bundle savedInstanceState) {     super.onCreate(savedInstanceState);     setContentView(R.layout.activity_main2);     ViewPager vpPager = (ViewPager) findViewById(R.id.viewpager);     adapterViewPager = new MyPagerAdapter(getSupportFragmentManager());     vpPager.setAdapter(adapterViewPager);      // Give the TabLayout the ViewPager     tabLayout = (TabLayout) findViewById(R.id.sliding_tabs);     tabLayout.setTabGravity(TabLayout.GRAVITY_FILL);     tabLayout.setTabMode(TabLayout.MODE_FIXED);     tabLayout.setupWithViewPager(vpPager);      // Attach the page change listener inside the activity     vpPager.addOnPageChangeListener(new ViewPager.OnPageChangeListener() {  }  @Override public void onSaveInstanceState(Bundle outState) {     super.onSaveInstanceState(outState);     outState.putInt(POSITION, tabLayout.getSelectedTabPosition()); }  @Override protected void onRestoreInstanceState(Bundle savedInstanceState) {     super.onRestoreInstanceState(savedInstanceState);     viewPager.setCurrentItem(savedInstanceState.getInt(POSITION)); <----------- LINE 68 }   Hi, I'm following this  to learning (Getting or Selected the Current Page). Stating that I can save and restore the last known tab position by implementing methods on onSaveInstanceState() and onRestoreInstanceState() to persist this data during screen rotation.  But I'm getting NPE on line 68. Help is much appreciated. Thanks!


The  spell states:  You ignore all objects and effects that aren't on the Ethereal Plane, allowing you to move through objects you perceive on the plane you originated from. When the spell ends, you immediately return to the plane you originated from in the spot you currently occupy. If you occupy the same spot as a solid object or creature when this happens, you are immediately shunted to the nearest unoccupied space that you can occupy and take force damage equal to twice the number of feet you are moved.  This is pretty straightforward for smaller objects, like weapons and items, and is discussed in  In this post, the bounty-winning answer cites :  For the purpose of these rules, an object is a discrete, inanimate item like a window, door, sword, book, table, chair, or stone, not a building or a vehicle that is composed of many other objects.  I assumed that Etherealness allowed travel through walls, as they are composed of multiple objects; however, this answer implies a composition of objects is not an object. Additionally, if a wall or large object like a vehicle is not an object, what is the point of the damage/ejection clause in the spell? I'd like to know what the limits are for passing through things on the Ethereal Plane. In particular, please answer the following questions with as much RAW support as possible:  Is it possible to pass through a building? Is it possible to pass through the ground? Is there anything that has mass and is neither a creature nor an object? If so, please provide examples and indicate whether it falls into an explicit class of its own, analogous to objects and creatures.  If the answer to either of the above is no, I am interested in a lore-based reason why this isn't possible.

In the PHB, on page 193, the Use an Object action is described:     Use an Object      You normally interact with an object while doing something else, such as when you draw a sword as part of an attack. When an object requires your action for its use, you take the Use an Object action. This action is also useful when you want to interact with more than one object on your turn   But what exactly is considered an object?  More specifically:  Is an arrow an object? Are weapons, armors, and shields objects?


Let $\mathfrak{R}$ be a commutative ring with identity. Show that if there exists a monic polynomial $p(x)\in \mathfrak{R}[x]$ of degree at least one such that the ideal $(p(x)) \subseteq\mathfrak{R}[x]$ is maximal, then $\mathfrak{R}$ is a field.   Thanks.

I don't see how to solve the following problem:     Let $R$ be a commutative and unitary ring. If there exists a monic polynomial $f(x) \in R[x]$ so that $R[x]/(f(x))$ is a field, show that $R$ is a field. What about if $f(x)$ isn't monic?   I don't have a clue about how proving it. I see that if $R$ is a field and $f(x)$ a monic and irreducible polynomial in $R[X]$ then $\frac{R[x]}{(f(x))}$ is a field, but that is not the question!  Thank you in advance for your help


I read sometime ago a short sci-fi story. It's about 2 astronauts from Earth traveling to an other planet. On their way to that planet they get intercepted by an alien vessel. The captain of that ship tells the 2 astronauts about an enemy that kills billions of aliens in the milky way. There was a big war and the bad aliens got killed, but they send ships out to search if there were more.  When one of the astronauts asks if they ever found one of the enemies,  the captain said not till today.

I may have encountered this short story in Asimov's Science Fiction magazine. Human explorers encounter an alien spacecraft. Aliens are cautiously friendly, but then tell the humans about an ancient, brilliant and cruel race of beings that conquered and destroyed every civilization they encountered. They were finally defeated and destroyed, or so it was thought, but their home world was never found. It turns out that this powerful, vicious race was in fact, Earthlings.


I recently purchased a DELL Inspiron 15 3000 Series laptop.  I created an Ubuntu 16.04 Live Installation DVD. However, when I attempt to create a dual boot of Ubuntu 16.04 and Windows 10, the Ubuntu Live Installation DVD puts the laptop into "sleep" mode and it never wakes up to allow me to complete the installation of Ubuntu.   After I boot from the Ubuntu Live installation disk, I see the Ubuntu loading screen with the 4 dots under the logo, but from there my monitor shuts off.  I can hear the hard disk still working.  I tried leaving the machine alone for hours in case my processor is just slow (only 1.6 ghz intel pentium), but that doesn't help, the machine never comes out of sleep mode to allow me to install Ubuntu.  I even verified the integrity of the Ubuntu Live Installation disk by booting from it in my old laptop and it worked perfectly.  I believe that there may be some type of driver conflict that will not allow me to finish installation... any ideas?  Big Ubuntu fan... why can't install it?

I am trying to boot Ubuntu on my computer.  When I boot Ubuntu, it boots to a black screen.  How can I fix this? Table of Contents:


I am trying to downgrade my ubuntu version, from 16.10 to 16.04... but from what i have read, that is not possible, which is why i decided to uninstall my ubuntu...  The other problem is, my laptop is a full ubuntu, a single boot... which is why i can't erase ubuntu from windows.. any suggestion?  Right now, i am trying to uninstall ubuntu using the bios, is it possible?  There are also suggestion, that i have to install windows first, then i uninstall the ubuntu from the windows... and download ubuntu back, which takes a lot of time, any other way?

I would like to see a full how-to guide on how to install Ubuntu.


I am seeing the zip file content using   unzip -l files.zip | less  but it outputs in ls style , is it possible to to display output in tree command style

Per the answers  I'm able to list the contents of my tarball in ls format. However, I'd like to be able to list them in tree format, i.e. something like the latter instead of the former:  With tar:  $ tar -tf foo.tar  foo/ foo/baz/ foo/baz/qux/ foo/baz/qux/hisfile.txt foo/bar/ foo/bar/myfile.txt foo/bar/yourfile.txt   With tree:  $ tree foo foo ├── bar │   ├── myfile.txt │   └── yourfile.txt └── baz     └── qux         └── hisfile.txt   Is it possible to do this without extracting the tarball? I'd prefer to have to avoid extracting the tarball due to their size.


The error message is following. Although I have found some data in Internet. I still have no idea about this error. Hope someone help me. Does this problem come from building systems? Undefined symbols for architecture x86_64: "operator<<(std::__1::basic_ostream<char, std::__1::char_traits >&, Stack&)", referenced from: Path(int, int) in main.o ld: symbol(s) not found for architecture x86_64 clang: error: linker command failed with exit code 1 (use -v to see invocation) #include <iostream> using namespace::std;  struct offsets{     int a,b; }; enum directions{N,NE,E,SE,S,SW,W,NW};   struct Items{     int x,y,dir;     Items(){};     Items(int a,int b,int d){         x=a;         y=b;         dir=d;     } };  template<class T> class Stack{ public:     Stack(int stackcapacity);     bool Isempty()const;     T& Top()const;     void Push(const T& item);     void Pop();      private:     T* stack;     int top;     int capacity;     friend ostream &operator<<(ostream &os, Stack<T> &s); };  template<class T> Stack<T>::Stack(int stackcapacity):capacity(stackcapacity){     if(capacity<1)         throw "stack capacity must be >0";     stack=new T[capacity];     top=-1; }  template<class T> inline bool Stack<T>::Isempty()const{     return top==-1; }  template<class T> inline T& Stack<T>::Top()const{     if(Isempty())         throw"stack is empty";     return stack[top]; }  template<class T> void Stack<T>::Push(const T &x){     if(top==capacity-1)     {         T *temp=new T[2*capacity];         copy(stack,stack+capacity,temp);         delete[]stack;         stack=temp;         capacity*=2;     }     stack[++top]=x; }  template<class T> void Stack<T>::Pop(){     if(Isempty())         throw "stack is empty";     stack[top--].~T(); }  template<class T> ostream& operator<<(ostream& os,Stack<T>&s){      os<<"top="<<s.top<<endl;     for(int i=0; i<=s.top;i++){         os<< i <<":"<<s.Stack[i]<<endl;     }     return os; }          ostream& operator<<(ostream& os,Items& item){     return os<< item.x<<","<<item.y<<","<<item.dir; }

Quote from :     The only portable way of using templates at the moment is to implement them in header files by using inline functions.   Why is this?  (Clarification: header files are not the only portable solution. But they are the most convenient portable solution.)


If $X_1,...,X_N$ are independent and identically distributed exponential random variables, what can be said about the distribution of $\text{min}(X_1,...,X_N)$ when $N$ is random and modelled as a Poisson random variable?

If $X_1, ..., X_n$ are independent identically-distributed random variables, what can be said about the distribution of $\min(X_1, ..., X_n)$ in general?


I can't figure out how to add element to pandas column for single row.  index = ['a','b','c','d'] df = pd.DataFrame(index = index) df['Col'] = [[]] * len(index)  df.loc['d','Col'].append('AA')   returns:      Col a   [AA] b   [AA] c   [AA] d   [AA]   I look for value 'AA' to be in the last row only.

I needed to create a list of lists in Python, so I typed the following: my_list = [[1] * 4] * 3  The list looked like this: [[1, 1, 1, 1], [1, 1, 1, 1], [1, 1, 1, 1]]    Then I changed one of the innermost values: my_list[0][0] = 5  Now my list looks like this: [[5, 1, 1, 1], [5, 1, 1, 1], [5, 1, 1, 1]]    which is not what I wanted or expected. Can someone please explain what's going on, and how to get around it?


I am trying to read data from excel using pandas.ExcelFile() into a dataframe, and then outputting a text file using to_csv.   This output text file should be at precision of 20 decimal places and rounded to 20 decimal places.  If an input value in excel is .005, my code converts it to 0.0050000000000000001 which is incorrect because of the very last digit.  It should be 0.0050000000000000000  Here's my code:   dataFrame = pd.ExcelFile("xlFile.xlsx") pd.set_option("display.precision", 20) dataFrame.ColumnToRound = dataFrame.ColumnToRound.round(20) dataFrame.to_csv("out.txt", index=False, sep='\t', float_format='%.20f')   The INPUT excel file would look like this (just one column and one value for simplicity):  ColumnToRound  .005  I have tried using the kwarg float_precision='round_trip' when reading the excel file using pandas.ExcelFile(), but it did not make a difference.    Side note: yes, I know 20 decimal places is a lot and probably more than necessary, but it was not my decision.  It has to be 20 decimal places.

Consider the following code:   0.1 + 0.2 == 0.3  ->  false   0.1 + 0.2         ->  0.30000000000000004   Why do these inaccuracies happen?


I try to produce a thematic map in QGIS, like this one done in MapInfo:    I want to do this in QGIS. I work in projection "Albers-Siberia" projection ( PROJ.4: +proj=aea +lat_1=52 +lat_2=64 +lat_0=0 +lon_0=105 +x_0=18500000 +y_0=0 +ellps=krass +units=m +towgs84=28,-130,-95,0,0,0,0 +no_defs). The latitude/longitide grid I made with help of this . I have got the following result:   I have a problem:  As you can see grid lines don't intersect in the North Pole. How     can I solve this problem?

My grid overlaps labels placed on a map.   Is there a way of forcing the labels to be displayed in front/on top and the grid placed behind the text?   Despite looking I cannot find a solution.     Using QGIS 2.18.15


I want to alert that "Please enter file .docx and .pdf" so I need the extension of the file...   $(".upload").click(function () {   var filename = $("#file").val();  var extension = " ";  })

See code:   var file1 = "50.xsl"; var file2 = "30.doc"; getFileExtension(file1); //returns xsl getFileExtension(file2); //returns doc  function getFileExtension(filename) {     /*TODO*/ }


Why is that in absence of a manually fixed point, a body shows its turning effect on application of a torque with its axis of rotation through its centre of mass? my attempt: is there a definition of the centre of mass that im mising?

If a sphere has a torque vector coming out of it at point A, would the sphere rotate about its center or the axis of the torque vector?