What does *tuple and **dict mean in Python?

As mentioned in PythonCookbook, * can be added before a tuple. What does * mean here?  Chapter 1.18. Mapping Names to Sequence Elements: from collections import namedtuple Stock = namedtuple('Stock', ['name', 'shares', 'price']) s = Stock(*rec)  # here rec is an ordinary tuple, for example: rec = ('ACME', 100, 123.45)   In the same section, **dict presents:  from collections import namedtuple Stock = namedtuple('Stock', ['name', 'shares', 'price', 'date', 'time']) # Create a prototype instance stock_prototype = Stock('', 0, 0.0, None, None) # Function to convert a dictionary to a Stock def dict_to_stock(s):     return stock_prototype._replace(**s)   What is **'s function here?


I have made the svg file and imported and then converted to curve. As i have make with the red is my original mesh and the below is unmark bevel mesh.  I want my mesh to be bevel from the center and it should not created space or gap as seen the below mesh. The mesh should make bevel from the center mark in green.  Im i doing correct way or is there any other way or how should i make the bevel without creating gap or space in middle of mesh.  As the mesh is present same shape should be bevel from the center.    result    Reference image


Why have the subjunctive and indicative converged in Modern English?

It is to me a curious fact that the  of verbs in English has so nearly disappeared in modern times. In fact, even the correct form and usage of the subjunctive in Modern English barely distinguishes itself from the indicative! In many regions and dialects, the subjunctive would appear to be entirely obsolete, replaced by the indicative in all cases. (Educated speakers, certainly in Britain at least, do however still make good use of it.)  The present subjunctive form in  is (in almost all cases) virtually identical to the third-person plural present indicative (e.g. 'He were', 'She own'). This is markedly different from , where the subjunctive form a form was . Even by the advent of Early Modern English in the 16th century, the subjunctive was already converging with the indicative.  Other Modern European languages, not only Romance ones such as French and Spanish, but Germanic languages related to English (e.g. Dutch/German) have a much more pronounced subjunctive form. From what I remember of my Classical Latin, word suffixes for a variety of tenses are hugely obvious in the subjunctive.  My question is: why is this convergence of the subjunctive and indicative so strongly the case in Modern English? Is it a general trend in other Germanic/Romance (or more generally Indo-European) languages? Why is its disappearance so much more apparent in English than other related languages?


There are 5 points on a plane, from which no 3 points are collinear. Proove, that from this points you always can choose 3, which are vertices of obtuse triangle. I already figured out, that they must form a Pentagon, but I cannot come up with ang idea.


How to use an escaped file-name string saved within a bash variable in a new shell command?

Problem:  I have an escaped string saved within a variable:  escapedFileName='/dbDumps/Mon\ Oct\ \ 1\ 15\:22\:50\ UTC\ 2018.sql'   but whenever I try to use this file name within the following command, I get an error message saying that this path does not exist (even though it does).  /usr/bin/mysql -u root -pmypassword system < "$escapedFileName";   When i use the path and not the string it works :  /usr/bin/mysql -u root -pmypassword system < /dbDumps/Mon\ Oct\ \ 1\ 15\:22\:50\ UTC\ 2018.sql   What am I doing wrong ?


How to download all files from Ubuntu One?

I just installed Ubuntu 14.04, and Ubuntu One isn't installed by default and their download page says it comes pre installed, which doesn't help with anything.  I wanna move all my files from Ubuntu One to Dropbox, but downloading one file at a time from the browser and upload it again to dropbox will take way too long.  Is there any way to get Ubuntu One on Ubuntu 14.04? or somehow download all files from the Ubuntu One website?  I see they updated their site:


Wolfram Alpha wrong answers on $(-8)^{1/3}$ and more?

Wolfram Alpha doesn't give $-2$ for $(-8)^{1/3}$, and it absolutely fails to draw $f(x)=x^{1/3}$ - does anyone know why? Am I missing something very 'deep' Wolfram Alpha is trying to teach me?   Here's what the graph should look like:   And here's what Wolfram Alpha draws:


Filter to change the content of 404 page

I have created custom rewrite rules. These rules now go to 404 page as expected. I can use action hook template_redirect to change the template matching query_var.  But I don't want to create separate template files as the page structure depend on the current theme in use. Rather I just want to change the content and title. I have tried change the content using the_content filter, but it seems the filter doesn't even get called for 404 page.  I also tried loading index.php template and then using the_content filter, but it also doesn't work.  Is there any way to achieve this?


split windows in gnome-debian (stretch version) with shortcuts

It is really useful the shortcut Super+Left/Right for moving windows to the left/right (technically "view split of left/right"). My version is gnome-debian (gnome 3.22.3) stretch (stable), but I want more custom shortcuts:  For example Super+Left+Down to move one window to the bottom right part (useful for terminals), similar to the other shortcut but in the bottom part.  I don't know if there is an easy way to do this trough shortcuts, or if you need to modify some files, any tip will be welcome :)  NOTE: I mention terminals as an example, but I would like to do it with any windows if it's possible.


Why do companies have a fiscal year different from the calendar year?

There are many companies that have their year end occur on dates other than December 31.  What are the advantages to this?


We know that when a ray of light goes from denser to rarer medium, it bends away from the normal due to increase in its speed. But that means it bas been accelarated and a force acts on it. Am I right? Please explain.


How much reputation/points does one need to have in order to add a comment to a question?  Suppose, I see a question, but i do not want to answer it..all i want to do is add a comment on that question to ask for some details like asking the user to share some more code/inputs or stuff like that! So how much point/reputation do i need so that I get to see a      "add comment"   link below each each and every question i come across?   I would be glad if someone can share any inputs on this.  Thank you.


My old user account is deleted but I still can see my old comments. I want to delete them as well

I still see my comments that I posted from my deleted user account. How can I delete them?


Are these sentences correct?  I have found this in a website.  Bananas plus water results in faster weight loss.  Laying off exercise and allowing afternoon sweets reduces stress.  Appreciate the help.


Calculating distance between two sets of Decimal Degree coordinates?

I have coordinates in decimal degrees e.g: point A:Lat,Lng(5.317101667,-2.023303333) and point B:lat,lng(5.317093333,-2.023318333). The altitude in Meters at Point A is 11m and the altitude and Point B is 33m, How can i accurately calculate the distance between these points? Note I know about Haversine, howeve,r these points are close to each other and I want an accurate way to calculate the distance between these two, would finding the distance between the points with d=sqrt(x2-x1)^2+(y2-y1)^2+(Z2-Z1)^2, be accurate? if so what units would the answer be in? I am looking to get the answer in metres.


java.lang.NullPointerException when reading from a text file

I am working on a coursework and I'm facing an exception when I try to load from a text file.  I am trying to store the IDs and the Questions.  The output should be :   {285 = Fill in the blank. A Node is generally defined inside another class, making it a(n) ____ class. } {37 = How would you rate your programming skills?}    This is inside the textfile :  258 MC Question Fill in the blank. A Node is generally defined inside another class, making it a(n) ____ class. Answer Private Inner Public Internal Selected 2  37 L5 Question How would you rate your programming skills? Answer Excellent Very good Good Not as good as they should be Poor Selected -1     public static void main(String[] args) throws IOException {   try (BufferedReader br = new BufferedReader(new FileReader("questions.txt"))) {     Map < Integer, String > map = new HashMap < Integer, String > ();   String line = br.readLine();     while (line != null) {    String[] temp;     temp = line.split(" ");    int id = Integer.parseInt(temp[0]);     line = br.readLine();    line = br.readLine();     String question = line;    line = br.readLine();    line = br.readLine();     while (line.trim() != ("Selected")) {      line = br.readLine();     }     line = br.readLine();    int selected = Integer.parseInt(line);    line = br.readLine();     map.put(id, question);    System.out.println(map);   }  }  }   When running the code I'm getting :      Exception in thread "main" java.lang.NullPointerException     at   daos.test.main(test.java:47) C:\Users\droop\Desktop\DSA\New   folder\dsaCW2Template\nbproject\build-impl.xml:1076: The following   error occurred while executing this line:   C:\Users\droop\Desktop\DSA\New   folder\dsaCW2Template\nbproject\build-impl.xml:830: Java returned: 1   BUILD FAILED (total time: 0 seconds)


Proof: $\mathbb{Z}_2 \oplus \mathbb{Z}_6 \not \cong \mathbb{Z}_{12}$

I have the following question :     Proof : $\mathbb{Z}_2 \oplus  \mathbb{Z}_6 \not \cong \mathbb{Z}_{12}$   The problem is that I think that  $\mathbb{Z}_2 \oplus  \mathbb{Z}_6 \cong \mathbb{Z}_{12}$. I don't understand why is the following not an injective and surjective function:  $$f:\mathbb{Z}_{12} \rightarrow \mathbb{Z}_2 \oplus  \mathbb{Z}_6$$ for all $a\in \mathbb{Z}_{12}$ so that $f(a)=(a \mod 2,a \mod 6)$.  I'm not really sure how to approach such questions, in general when asked proof/disproof $\mathbb{Z}_x \oplus  \mathbb{Z}_y \cong \mathbb{Z}_{xy}$, Any tips? Any ideas?  Thank you!


Squeeze/Sandwich Theorem Involving $n^{th}$ root: $\lim _{ n\rightarrow \infty }{\left(3^n+1\right)}^{\frac 1n}$

Find $\lim _{ n\rightarrow \infty  }{ { \left( { 3 }^{ n }+1 \right)  }^{ \frac { 1 }{ n }  } } $ using the squeeze theorem  I have come across ways to do this but none mention the squeeze (or sandwich) theorem. I know I need to find $2$ functions which squeeze the given function but can only think of using $(3^n)^{1/n}$ i.e. $3$ as the $\le $ function


Consider two buttons: - OK - Cancel  Should the positive 'OK' button be placed on the right or left? Is there some rule or convention that needs to be followed in this case. Consider the following image. There's an Approve button and Decline link. - Should the Approve button be on left or right of Decline? - Should the 'Decline' option be a button as well or should it be a link?


$\sum_{k=0}^{n}{k\binom{n}{k}}=n2^{n-1}$  $n2^{n-1} = \frac{n}{2}2^{n} = \frac{n}{2}(1+1)^n =  \frac{n}{2}\sum_{k=0}^{n}{\binom{n}{k}}$  That's all I got so far, I don't know how to proceed


It looks something is going wrong with persist method of EntityManager class. I use apache tomcat and recieve HTTP Status 500- page every time I try.  This is DataQuery class:  public class DataQuery {     EntityManagerFactory emf;     EntityManager em;      public DataQuery() {         emf = Persistence.createEntityManagerFactory("com.sbu.ac.jobyab");         em = emf.createEntityManager();         em.getTransaction().begin();     }      public void registerUser(Employee e){         em.persist(e);     } }   And this is the registerController class that recieves input from user and do the registeration task:  public class registerController extends HttpServlet {     private DataQuery query;     @Override     protected void doPost(HttpServletRequest request, HttpServletResponse response)             throws ServletException, IOException {         String email = request.getParameter("register_email");         String pwd = request.getParameter("register_password");         Employee e = new Employee(10, email, pwd);         query.registerUser(e);     } }   This is full stack error :     type Exception report      message      description The server encountered an internal error that prevented it   from fulfilling this request.      exception      java.lang.NullPointerException     com.jobyab.controllers.registerController.doPost(registerController.java:39)     javax.servlet.http.HttpServlet.service(HttpServlet.java:648)     javax.servlet.http.HttpServlet.service(HttpServlet.java:729)     org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)   note The full stack trace of the root cause is available in the Apache   Tomcat/8.0.33 logs.


Extension of Lipschitz continuous functions

Let $X$ be a metric space, let $K$ be a subset of $X$, and let $f:K\to\mathbb{R}$ be a Lipschitz continuous map with some Lipschitz constant $L$ (thus $|f(x)-f(y)|\leq Ld(x,y)$ for all $x,y\in K$) Show that there exist an extension $\widetilde{f}:X\to\mathbb{R}$ with the same Lipschitz constant $L$.   I know that we can extend $f$ to the closure of $K$ with the same Lipschitz constant, thus we may assume $K$ is closed. If we then use Tietze extension theorem,  we can get of continuous extension $\widetilde{f}$ of $f$, but $\widetilde{f}$ may not be Lipschitz continuous with Lipschitz constant $L$. The hint says that a "greedy" algorithm will work here: pick $\widetilde{f}$ to be as large as one can get away with. I don't understand what the "greedy" algorithm is.


I am aware of some theorem that says that if $M$ is non singular, $\det(M) \neq 0$, then: $$\mathrm{card}(\mathbb{Z}^n/M \mathbb{Z}^n)= |\det(M)|.$$ How does one prove this? Figured if I put in the context of the rational canonical form, this would help, but cant piece it together.  Thanks.  This result is mentioned in the first answer of this question:  .


Proving if $\sum a_n ^2 < \infty$ then $\sum \frac{a_n}{n}$ converges absolutely

I was thinking of using Ratio test but I have been unsuccessful so far. It's sufficient for me to show that $\lim_{n \to \infty} \left| \frac{a_{n+1}}{a_{n}} \right|$ converges to $l <1$.  By hypothesis, we have that $\sum a_n ^2 < \infty$, hence, $\lim a_n =0$. But $\lim a_n =0$ is a much weaker hypothesis to prove that $\lim_{n \to \infty} \frac{a_{n+1}}{a_{n}}$ converges to some $l <1$. Because $\left( \frac{1}{n} \right)$ converges to $0$ but $\frac{1/(n+1)}{1/n}$ converges to $1$.  I don't need solutions, some hints would be enough for me to finish this.


Limit of sequence $ S_n $=$\int_0^1 \frac{nx^{n-1}}{1+x}dx $

Let $ S_n $=$\int_0^1 \frac{nx^{n-1}}{1+x}dx $ for n$ \ge $1 then as n tends to infinity sequence tends to:  1.0 2.1 3. 1/2 4. Infinity  Is there any other way, than to first do integration, and then take limit?


My number is associated with iMessage on other phone, how to remove it?

Good day everyone. For only 1 hour (!) I used my relatives iPhone with my sim card and that's it, he keeps receiving all of my iMessages. I tried checking in iTunes all devices associated with my account and his device is not listed. I tried to log in and log out to/from iMessage on his phone with his apple ID, still won't help. How can I stop this nightmare!? When I go to iMessage settings>Send & Receive on his device, there is only my phone number listed, how do I remove it without smashing phone to the wall?! Thanks and have a great day  EDIT. After talking to apple support for some time, they removed my phone number from my friend's iMessage. So I guess if you are facing same problem you have to contact support.


Demonstrate an interaction with a design component

We have a mobile music application that has a header with a floating button underneath it, something along the lines of this crude image:    People understand to click the button to play a song, but it is not obvious to them that can swipe the button left or right to move to the previous or next track.  Is there a cue we can use? Or does anyone have any guidance on creating a tutorial we can fire up when the user first starts the app?


Maybe this is for dummies, but i'm not sure. My directory has the permissions:  drwx------ 2 root   root 4096 oct 16 11:39 scripts   But the script have the permissions:  -rwxrwxrwx  1 user user   39 oct 16 17:32 script.sh   But when i try to execute the script i get  bash: script.sh: Permission denied   I don't understand what is happening, because user can't execute the script (the owner and group were changed manualy) and obviusly root can.


Any special tactics for SEO OFF page in independent and movie video songs website?

For Independent music video songs website how do the SEO OFF page. For content site we can submit in article submission, directory submission, social bookmarking etc. can i follow same process in my music site. I have some target keywords (tamil songs, independent tamil songs) to this keywords how to do in search results.


A problem from Evans' PDEs book: find a Lagrangian for a given Euler-Lagrange equation

Find $L=L(p,z,x)$ so that the PDE:      $-\Delta u +D\varphi \cdot Du =f $   is the Euler-Lagrange equation corresponding to the functional $I[w]:=\int_UL(Dw,w,x)dx$.  (Hint,:Look for a Lagrangian with an exponential term),  We can easily to calculate an equation's Euler-Lagrange  equation, while the inverse calculation I feel hard for me ,and I still don't know how to use the Hint! Thanks a lot!


I am trying to store form data into database using mysqli but it is generating query error my code is given below.... When ever I try to submit the database connection is generating.. the $_POST is working perfectly.. the error only generating by mysqli_query..  <?php  $name = $_POST["firstname"] . " " . $_POST["lastname"]; $email = $_POST["email"]; $happen = $_POST["whendidhappen"]; $howlong = $_POST["howlong"]; $howmany = $_POST["howmany"]; $describe = $_POST["describe"]; $whattheydid= $_POST["whattheydid"]; $seenmycat = $_POST["seenmycat"]; $anythingelse = $_POST["anythingelse"];   $dbc = mysqli_connect('localhost','root','','abductionreport')  or die('Database connection error');   $query = "INSERT INTO abductionform (firstname, lastname, email,whendidhappen, howlong, describe, whattheydid, seenmycat,anythingelse)VALUES('$name','$name','$email','$happen','$howlong', '$howmany','$describe','$whattheydid', '$seenmycat','$anythingelse')";    $result = mysqli_query($dbc,$query) or die ("Query Error");  mysqli_close($dbc);     ?>
Aliens Abducted Me - Report an Abduction

Thanks for Submiting the form.
 <?php  echo "$name it happend to you on $happen it take $howlong
"; echo "Number of aliens: $howmany
"; echo "Describe: $describe
"; echo "What they did to you: $whattheydid
"; echo "Have you seen my cat: $seenmycat
"; echo "Anything else : $anythingelse
"; echo "Your Email Address is : $email
";  ?>


I simply want to delete the bulk if not all of several hundred photos I have uploaded from my camera, to free up space as it is already full. However I cannot find how to delete them unless I do it one by one which requires at least three different actions and would take forever! Someone said highlight first and then delete, but I cannot find any control to highlight them! I went to the nearest Apple shop today. It is 125 kms from where I live. Apparently it does not open until 9.30 am and at 9.10 there are already 30-40 people patently waiting outside! I do not have time for this, and returned to pay $6 for parking my car!  I SIMPLY WANT TO KNOW HOW TO DELETE GROUPS OF PHOTOS. The photos I want are already transferred to my PC, so even it they are deleted from Cloud it does not matter, but at present when I go travelling I will not be able to download photos as I take them.


Why the extra term $\frac{1}{2}(\partial_{\rho}A^{\rho})^2$ in the photon Lagrangian?

In my quantum field theory class we have been told to use this Lagrangian for the photon field  $$\mathcal{L}=-\frac{1}{4}F_{\alpha\beta}F^{\alpha\beta} -\frac{1}{2}(\partial_{\rho}A^{\rho})^2.$$  but the reasons have been kept quite obscure. Why do we do this? We don't we stick with the good old Maxwell Lagrangian? Doesn't this extra term change things? and if not (as I suppose it is) why not?


The new edit rejection message for "no improvement whatsoever" sounds too hostile

As you may have noticed, the edit rejection reasons were . And that's what we need to talk about: They have been live for about three weeks now, and, and least on , it has been repeatedly noted1 by reviewers and reviewed ones alike that the rejection messages sound far more hostile than the old ones. The main culpit is no improvement whatsoever, which reads:  This edit fails to make the post even a little bit easier to read, easier to find, more accurate or more accessible. Changes are either completely superfluous or actively harm readability.  Now, you may say that it is an accurate description of what no improvement whatsoever means. However, to the reviewed editor it sounds quite passive-agressive on the part of the reviewer, especially since there is no indication that this is a canned response (or at least, many reviewed editors seem not to know that it is canned). A minimal proposal would be to dial down on the emphasizing phrases like even a little bit, perhaps changing it to something like  This edit is unnecessary as it does not make the post easier to read, easier to find or more accurate.  At least to my ears, this sounds far more level-headed. It's really not necessary to hammer the point home with calling the edit superfluous or actively harmful after you've already told the reviewer why the edit hasn't been approved. Especially in light of the  saying  Be welcoming, be patient, and assume good intentions.  I think the current rejection message needs to be changed.  1Examples are  in chat and  on our meta. A non- example would be in the  to the official blog post.


Output from commands in one terminator window displayed in another by default?

I have a split window setup for terminator and was wondering if there was a way to set it up such that the default is to run the commands from one window in the other.  I know that what I need to do is find a way to append "> /dev/pts/17" (my terminator window) to the end of every command. Is the way to do this by editing .bashrc?


How to safely remove a Ubuntu-Windows dualboot?

I tried to do this one time before, but it completely failed. I wiped all of it's partitions, and reclaimed the partitions within Windows, however, that messed up GRUB and I couldn't get back the the Windows Boot Manager. Then, I had to remove Windows and completely wipe my HDD, and reinstall Windows. I've redone a dual boot, but I'm looking to remove. Can someone please help me fix this problem so that it doesn't happen again?


Mass Effect 2 and 3 - Any way to stop Garrus Dying?

Firstly i just want to apologise if any of my information is incorrect. I took a long (Hopefully long enough) look at the Garrus Vakarian information on the Mass Effect Wikia page.  I notice in ME2 and 3, there's a risk of Garrus dying (Higher in ME3 apparently). I'd like to save him as i think he's quite an awesome squad member and character overall. I am partway through ME2, have just recruited Mordin after getting Garrus and done a few side-missions (Last one completed was the mechs destroying some crates..cant recall exact mission name). From what i can tell Garrus in ME2 will only die if i dont save him in time when on the bridge at Omega, if thats so then thats that sorted already. As for ME3 there seems to be a specific set of things that need to happen or Garrus, and alot of other normandy crew and squad will die at the end, of course i want to avoid this in my first playthrough so want to be prepared for it when i play ME3!  Any information is appreciated! :D


SE Ask Question page bug - affects multiple sites

The Ask Questions page seems to have some issues with the menu on the right.  I noticed it in Workplace and it also seems to affect Meta-SE.  This is not a duplicate of ""  because it is the opposite of what that question is reporting.  e.g.) The menu is NOT covering the footer properly.  To replicate, I simply scroll to the bottom.  I am on Windows 8 running Chrome Version 46.0.2490.71 m  The ask page on SO seems fine.


$N_1,N_2,N_3 \unlhd G, N_i\cap N_j =\{e\}, G = N_iN_j$. Want to show that $G$ is abelian, $N_i$ are isomorphic.

The following is a problem from the Berkeley Problems book.      Let $G$ be a group with three normal subgroups $N_1$ , $N_2$, and   $N_3$. Suppose $N_i \cap N_j = \{ e\}$ and $N_iN_j  = G$ for all   $(i,j )$ with $i \ne j$ . Show that $G$ is abelian and $N_i$, is   isomorphic to $N_j$ for all $i, j$ .   Attempt:   I have not got very far. The only thing that comes to my mind is that as $|HK|=\frac{|H||K|}{|H \cap K|}$, $|N_1|=|N_2|=|N_3|=m$, and order of $|G|=m^2$. I have made other futile attempts of trying to show m prime, finding an isomorphism between the $N's$. I think the fact that the equation $N_i N_j=G$, could be seen as, left coset of $N_j$ with the multiplying elements restricted to only $N_i$ could provide me an answer, but I haven't got anywhere with this.   Thanks in advance.


I try to install steam on my laptop but when I try to open the steam, there is a notice says that "Couldn't set up Steam data - please contact technical support". What should I do? Please help me what to do right now


Are sites proposed on Area 51 allowed restrict access to a group of people smaller/more specific than "the general public"?  For example: only registered users of an existing web app?


Showing that the product of all $n$th Roots of Unity is $(-1)^{n+1}$

I need to show that the product of all the $n$th roots of unity is $(−1)^{n+1}$.   Is there a way to do this by induction? If there is, I can't seem to figure it out. Are there other, perhaps more efficient, methods of proof?


This diode's datasheet seems to contradict itself; what is it really saying?

I'm looking for a diode with a forward voltage (VF) of 0.6 V at 10 mA IF. While searching for it, I came across many diodes' datasheets where they seem to contradict themselves. For example:    As in the table, it says VF is 0.855 V at 10 mA IF at 25 °C, while in Fig 1 it is around 0.75 V. For this one, it is just 100 mV difference, but I've seen other diodes with a higher difference. Which part of the datasheet should I use?


Someone told me that, Gaussian distribution is conjugate to distribution because a Gaussian times a Gaussian would still be Gaussian distribution ?  Why is that ? Say the following situation: $X\sim N(\mu_x,\sigma^2_{x})$ , $Y\sim N(\mu_y,\sigma^2_{y})$  Would a new variable, $Z=XY$ be normally distributed ??


I am new to this game, and will try to optimize my game-play as much as possible. I will do this by making macros for my spells and abilities.  Are there global cooldown on spells and abilities in League of Legends?  Since this is important regarding macros to trigger spell and ability combos.  A Global Cooldown(GCD) is a cooldown which affect most if not all abilities, spells or items when using an ability, spell or item.   In most games it is there to prevent macroing/spamming of multiple instant abilities, spells or items, and usually has a set short duration independent of the ability, spell or items normal Cooldown.


Commutative Ring: Nilpotent elements closed under addition?

Possible Duplicate:          Given a commutative ring $R$ and two nilpotent elements $r$, $s$ there exists an $n \in \mathbb{N}$ such that  $$ (r+s)^n = 0.$$  I want to prove that in order to show that the nilpotent elements of a commutative ring are closed under addition (to show that the nilpotent elements form an ideal within a commutative ring). Is that a good way to do it? I'm a little stuck.


When you die, what contributes to your "Score"?

When you die, 3 things happen.    You swear  A message appears in the chat log describing how you died A "You died" screen appears, with the options to quit or respawn, and a "Score".   What contributes to this score?


Downvotes vs comments on posts by new users

Stack Exchange has recently rolled out the .  Given that this comes with a reminder on the comments and answer sections, this is presumably intended to get people to be  in their answers and comments.  I also take this as an indicator that Stack Exchange is looking to improve retention of new users.  So are rude comments actually the problem for new users?  I posit that it's actually worse, from a user retention perspective, to down-vote a new user and not say anything than to give a rude yet informative comment.  Even something as rudimentary as pointing them to the FAQ or saying that opinion questions are out of scope gives them feedback that they can use to improve rather than telling them that they suck with no other information (down-votes with no comments).  Additionally, downvotes can snowball.  When you read answers with even a single downvote, you likely come in with the bias that the answer is bad, and are therefore less likely to read it in a favorable light.  I'm not proposing .  Instead, I'd like to consider something much more specific: requiring a comment when casting the first downvote on a post by a new user.  Do the data support this idea?  Ideal data would be numbers on the following three things:   The number of users whose first post was downvoted who then made additional posts over a week later The users in (1) with the additional condition that there was a comment on their first post The fraction of downvoted posts that have comments   EDIT: I'm looking for data not opinions.  This is not yet a feature request.  I'm already aware that people don't like the idea of mandatory comments, as I did my research before asking.  I'm looking for whether or not there is data on user behavior on stackexchange if possible or a related site if not.


How to test association in contingency tables with very small numbers and proportions?

I have a sample of 197 responses. 8.6% (17)are from Group A, the remainder from Group B. (The groups are mutually exclusive, and not independent). (If it helps visualize the issue, Group A is under 10's, Group B respondents aged 11+.)  The responses are then sorted in to groups by type. Type 1 is "head injuries", and there are 3 members of this group. 2 are from Group B, 1 is from Group A.  I would expect the results for head injuries to be under 10 (Group A) & head injury: 0.3 Under 10 & no head injury: 16.7 Over 10 (Group B) & head injury: 2.7 Over 10 & no head injury: 179.3  I have asked a few friends how to test if the expected value being so much lower than the observed value is significant. So far responses seem to favour a Z test, or a chi squared test with a correction for very small numbers. I'm innumerate in the extreme, but can manage either well enough -- just not sure what is the appropriate test here?


Bypass "Do you want to..." dialog after clicking script

After I create a bash script and double click it in Nautilus I am prompted with this - Do you want to run "sleepytime", or display its contents? With Run in terminal, Dislpay, Cancel and Run as options.    Is it possible to just choose "run" or "run in terminal" by default?


How to Sync iPhone contacts to a new Google account?

I have changed my Google account, now I want to sync my contacts to the new Google account. How can I do this?


What common materials absorb most infrared light?

I'm competing in a simple robotics competition where most of the participants use reflected infrared light to detect their opponent. I'd like to make my own robot as difficult to see as possible. What common materials (fabric, plastic, paint, etc) absorb most infrared light, and reflect as little of it as possible? I first thought any flat-black substance might do, but I've learned that what appears dark in the visible spectrum might still appear bright to infrared.


What practical workarounds exist for dealing with 'too long' file paths?

My workplace has a network drive anyone can access.  Because of this, there exist file paths which are so long that if you try to create a reasonably named file within them, the file path will exceed the maximum allowable length.  In some cases, I have authority to reduce the path length by removing redundancies, etc.  In other cases, it's part of a long standing project and I am forced to use that path.    How do I work with a shared network file path which is too long to allow files with practical names?  Edit: Please note, that if I could delete/revise the file path, I would.  The operating system is capable of updating the path.  The question, however, is that I am not authorized to update it.  That is, a senior colleague/manager says, "Do not change this file path."  What options are there for working within this constraint?  Looking around, these are the suggestions I have found:   Create a new folder somewhere else on the shared drive which has a shorter path.  Include a shortcut to the new folder at the end of the too long path.  A shortcut could be placed in the new folder which points to the too long folder. Change the hearts and minds of my colleagues.   Are there any others?


Error Propagation: Why using derivatives instead of the function

Suppose I've measured the length $l$ with an uncertainty $\Delta l$ in order to calculate the Volume of a cube $V = l^3$. If I were to add an error: why am I supposed to do it like $\Delta V = \sqrt{\left(\partial_l V\right)^2\,\left(\Delta l\right)^2}$ and not just $\Delta V = \left(l+\Delta l\right)^3-l^3$


Open Ubuntu Bash's GUI applications on Windows 10

I have installed Windows 10 Insider build just to use Ubuntu Bash. I noticed its entire Ubuntu on Windows so I tried to install a GUI app i.e. Gedit. It was installed properly but when I try to open it. I see an error   root@ACERASPIRE:~# gedit error: XDG_RUNTIME_DIR not set in the environment.  (gedit:3994): Gtk-WARNING **: cannot open display: root@ACERASPIRE:~#   Is it possible to fix this issue or get Ubuntu's GUI applications running on Windows 10. I think someone has a work around for this here


I am making a program that will allow the user to enter a name, which will then be added and displayed to a list in the jframe window, but cannot figure out how to add to the lsit using code.  I have tried several things, like:  lstNames.append(name); lstNames.Add(name); lstNames.add(name, this);   (name is a string)  Currently my code looks like this:  DefaultListModel model = new DefaultListModel(); JList list = new JList(model); ArrayList<String> names;  private void btnAddActionPerformed(java.awt.event.ActionEvent evt) {                                             String name = txtFirst.getText() + " " + txtLast.getText(); // works             names.add(name); // works      for (int i = 0; i < names.size(); i++) {         model.add(i, names.get(i));     }     lstNames.setModel(model);  }                                         I just want to add a name to a list, but all I get is errors, any help would be great.  Here are my errors:  Exception in thread "AWT-EventQueue-0" java.lang.NullPointerException     at javaapplication2.NewJFrame.btnAddActionPerformed(NewJFrame.java:99)     at javaapplication2.NewJFrame.access$000(NewJFrame.java:12)     at javaapplication2.NewJFrame$2.actionPerformed(NewJFrame.java:45)     at javax.swing.AbstractButton.fireActionPerformed(AbstractButton.java:2022)     at javax.swing.AbstractButton$Handler.actionPerformed(AbstractButton.java:2348)     at javax.swing.DefaultButtonModel.fireActionPerformed(DefaultButtonModel.java:402)     at javax.swing.DefaultButtonModel.setPressed(DefaultButtonModel.java:259)     at javax.swing.plaf.basic.BasicButtonListener.mouseReleased(BasicButtonListener.java:252)     at java.awt.Component.processMouseEvent(Component.java:6533)     at javax.swing.JComponent.processMouseEvent(JComponent.java:3324)     at java.awt.Component.processEvent(Component.java:6298)     at java.awt.Container.processEvent(Container.java:2236)     at java.awt.Component.dispatchEventImpl(Component.java:4889)     at java.awt.Container.dispatchEventImpl(Container.java:2294)     at java.awt.Component.dispatchEvent(Component.java:4711)     at java.awt.LightweightDispatcher.retargetMouseEvent(Container.java:4888)     at java.awt.LightweightDispatcher.processMouseEvent(Container.java:4525)     at java.awt.LightweightDispatcher.dispatchEvent(Container.java:4466)     at java.awt.Container.dispatchEventImpl(Container.java:2280)     at java.awt.Window.dispatchEventImpl(Window.java:2746)     at java.awt.Component.dispatchEvent(Component.java:4711)     at java.awt.EventQueue.dispatchEventImpl(EventQueue.java:758)     at java.awt.EventQueue.access$500(EventQueue.java:97)     at java.awt.EventQueue$3.run(EventQueue.java:709)     at java.awt.EventQueue$3.run(EventQueue.java:703)     at java.security.AccessController.doPrivileged(Native Method)     at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:76)     at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:86)     at java.awt.EventQueue$4.run(EventQueue.java:731)     at java.awt.EventQueue$4.run(EventQueue.java:729)     at java.security.AccessController.doPrivileged(Native Method)     at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:76)     at java.awt.EventQueue.dispatchEvent(EventQueue.java:728)     at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:201)     at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:116)     at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:105)     at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:101)     at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:93)     at java.awt.EventDispatchThread.run(EventDispatchThread.java:82)   No errors appear until, the button to run the code is pressed. Very basically, I want to add the user input to the jlist


Simple way to prove that $\mathbb{Z}[\sqrt[3]{2}]=\mathcal{O}_{\mathbb{Q}(\sqrt[3]{2})}$

Leting $\delta:=\sqrt[3]{2}$, prove that $\mathbb{Z}[\delta]$ is the ring of integers of $\mathbb{Q}(\delta)$.   Here's what I've done: let $K:=\mathbb{Q}(\delta)$. Since $[K:\mathbb{Q}]=3$, then $1, \delta, \delta^2$ are $\mathbb{Q}$-linearly independent (in particular, they are $\mathbb{Z}$-independent). Since $1, \delta, \delta^2$ are integers of $K$, we have that $\mathbb{Z}[\delta]=<1, \delta, \delta^2>_{\mathbb{Z}}\subset\mathcal{O}_{K}$.   To prove $\supset$, I did the following: if $z=a+b\delta+c\delta^2$ is an integer of $K$, its minimal polynomial $p(x)=x^3+c_2x^2+c_1x+c_0$ lies in $\mathbb{Z}[x]$ and has roots $\sigma_1(z),\sigma_2(z)$ and $\sigma_3(z)$, where   \begin{align*}  \sigma_1 &:\delta\mapsto\delta\\ \sigma_2 &:\delta\mapsto\omega\delta\\ \sigma_3 &:\delta\mapsto\omega^2\delta \end{align*}  are the embeddings fixing $\mathbb{Q}$ and $\omega^3=1$. Using Viète's relations we get:  \begin{align*}   c_2&=-\sum_{i}\sigma_i(z)= -3a\\          c_1&= \sum_{i<j}\sigma_i(z)\sigma_j(z)=3a^2-6bc\\  c_0&= -\prod_{i}\sigma_i(z)=-(a^3+2b^3+4c^3-6abc) \end{align*}  which gives us restrictions for $a, b, c$, since $c_0, c_1, c_2\in\mathbb{Z}$. Since $\delta z$ and $\delta^2 z$ are also integers of $K$, we calculate its respective minimal polynomials and find new restrictions for $a, b, c$.   After a very tiresome case analysis, I could prove that $a, b, c\in\mathbb{Z}$, concluding the proof.   This solution was given as a hint by the professor, and seems to me not very natural and, above all, way too long. My question is: is there a more natural and/or shorter solution for this? Thanks!


How to store output of awk to array with empty string on null values?

I have a variable animals.  animals=lion*tiger*elephant**cat***dog   I just want to split by the delimiter * and store it into an array.   Expected:   animals[0]="lion"  animals[1]="tiger"  animals[2]="elephant"  animals[3]=""  animals[4]="cat"  animals[5]=""  animals[6]=""  animals[7]="dog"   I used awk command but I don't know how to store empty string for no value.  echo "$(awk -F* '{ for (i = 1; i <= 8; i++) print $i }' <<< "$animals")"   Result:  lion tiger elephant  cat   dog   Array:  Array=($(awk -F* '{ for (i = 1; i <= 8; i++) print $i }' <<< "$animals"))  # Null values get neglected


Is there a general template for Proving the Irrationality of some Radical by Contradiction

I’ve consistently been made to solve a rather absurd number of problems that involve proving the irrationality of some radical (Nth Root of X) by Contradiction, and since these problems often use a very similar method of proving irrationality (assuming the radical is equal to a fraction in simplest form, then proving that the Numerator and Denominator have some common multiple. However, I was wondering if there exists some absolute definitive template to solve such a question, solved exclusively in variables to which numbers can be substituted. I do understand the naïveté of my question but I would greatly appreciate it if someone may explain this exists. As a side note: I have attempted to do this by stating: $$\mathrm{N^{th}-Root}(x) = \frac{a}{b}$$ $$x = \frac{a^n}{b^n}$$ $(b^n)x = (a^n)$, thereby proving that $a^n$ is a multiple of $b^n$, but I’ve gotten stuck. Again, I do not know what I am doing and would appreciate any help or explanation!


Extra slide in between itemize environment

My MWE:  \documentclass{beamer} \usepackage[english]{babel} \usepackage{calc} \usepackage[absolute,overlay]{textpos} \usepackage{pdfsync} \mode<presentation>  \title[AAA]{AAA} %\subtitle \institute[AAA]{BBB} \author{AAA} \date{BBB}  % Define the title of each inserted pre-subsection frame \newcommand*\titleSubsec{Next Subsection} % Define the title of the "Table of Contents" frame \newcommand*\titleTOC{Outline}  \begin{document}  \section{Section 1}  \begin{frame}\frametitle{Section 1 - A}     \begin{itemize}         \item <1-> Blablabla:             \begin{itemize}               \item Blablabla                 \item Blablabla                 \item Blablabla                 \item Blablabla                 \item $\cdots\cdots\cdots$             \end{itemize}         \vspace{0.5cm}         \item <2-> Blablabla:             \begin{itemize}               \item Blablabla                 \item Blablabla                 \item Blablabla                 \item Blablabla                 \item $\cdots\cdots\cdots$             \end{itemize}     \end{itemize} \end{frame}  \begin{frame}\frametitle{Section 1 - B}     PHOTO \end{frame}  \begin{frame}\frametitle{Section 1 - A}     \begin{itemize}         \item <1-> Blablabla:             \begin{itemize}               \item Blablabla                 \item Blablabla                 \item Blablabla                 \item Blablabla                 \item $\cdots\cdots\cdots$             \end{itemize}         \vspace{0.5cm}         \item <2-> Blablabla:             \begin{itemize}               \item Blablabla                 \item Blablabla                 \item Blablabla                 \item Blablabla                 \item $\cdots\cdots\cdots$             \end{itemize}     \end{itemize} \end{frame}  \end{document}   What I basically want is to get rid of page 2 and page 4 of the pdf output file. That is, on the first slide I want to show item <1>, then I want to show a slide with just a photo, and then I want to show item <1> together with item <2> on a new slide.


Does a constantly accelerating charged particle emit EM radiation or not?

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?


Is cloning a partially allocated 2 TB drive (src) to a 1TB drive (dst) possible?

I am thinking of trying to clone some clean installs of Windows OSes (dual-boot) from a (src) 2TB drive (1863 GB) to a (dst) 1TB drive (931.5 GB).    The 2 OS partitions on (src) would only be 200 GB total, and I could also have a data partition of 731.5 GB, for a total of 931.5 GB of allocated space (the rest of the (src) drive has not been partitioned).  So will Clonezilla, or if not what other cloning tool would, allow me to DISK clone the partially allocated 2TB (src) drive to the 1TB (dst) drive, since they both have the same amount of allocated space?


Find the sum $\sum_{k=1}^{\infty} \frac{1}{(k+2)\sqrt k + k\sqrt {k+2}}$

I don’t really know how to start here. I feel the series will telescope, but it’s not reducible to partial fractions


How can I split install.wim from Windows installation ISO on OSX?

I want to make a bootable Windows installation USB on OSX. However, I run into the problem with isntall.wim file that doesn't fit into FAT32 4GB file limit.  All google results about this problem () describe the solutions that I can use on a Windows system. How can I split the install.wim file if I only have a working OS X system? Is there anything similar to Dism /Split-Image console tool that I can use?


kernel panic: unable to mount root in ubuntu 16.04

I just booted up my ubuntu partition, it was working and I've installed the updates via the software updater but it crashed at the end, so I've restarted the pc and now I'm getting this:    I guess it's a kernel panic related to the hard drive. How can I fix this, I need to copy my SSH keys at least.  PS: I have windows 7 also installed on a different partition and it works fine.


How to simulate a binary response variable based on two non-interacting continuous variables

I want to simulate a binary response variable which depends on two normally distributed continuous variables, and I want to have more 1s than 0s in the response variable. I wonder how this can be done such that a logistic regression will not identify a significant interaction term.  My current approach in R looks like this:  n = 1e5 x1 = rnorm(n) x2 = rnorm(n) y = x1+x2+rnorm(n) y = ifelse(y > 2, 1, 0) df=data.frame(x1=x1, x2=x2, y=y) summary(glm(y ~ x1*x2, df, family=binomial(logit)))$coefficients   This usually results in a highly significant interaction term, even though the y is just the sum of x1 and x2. So how can I simulate a y which depends on both x1 and x2, but not on their interaction?


Complex matrices are similar over $R$ iff they and thier conjugates are similar over $C$.

Prove that there is a nonsingular $T \in M_n(R)$ such that $A = TBT^{−1}$ if and only if there is a nonsingular $S \in M_n$ such that both $A = SBS^{−1}$ and $\bar{A} = S\bar{B}S^{−1}$. (Here $M_n$ is the set of $n \times n$ complex matrices).  If direction: We can take $S = T$ i.e. imaginary part being zero. Then, $A = SBS^{-1}$ obviously. Moreover, $\bar{A} = \overline{SBS^{-1}} = \bar{S}\bar{B}\bar{S^{-1}} = S\bar{B}S^{-1}$. The only if direction: Let $S = H+iC$ and $\bar{S} = H-iC$ where $H,C \in M_n(R)$. Then, $A = SBS^{-1} = (H + iC)B(H+iC)^{-1}, \bar{A} = \bar{S}\bar{B}\bar{S^{-1}} = (H-iC)\bar{B}(H-iC)^{-1} = S\bar{B}S^{−1} =(H + iC)\bar{B}(H+iC)^{-1}$. I guess I should show that $S = \bar{S}$ i.e. $H+iC = H - iC$. Because if complex conjugate of $S$ is equal to $S$ then $S \in M_n(R)$ so, we will complete the proof.


I'm working on some scripting:  for x in `find ./ -name *.pdf` do   echo pathname $x done   My filenames are Test1 ( Volume II), Test2 ( Volume II). I'm getting a return of  pathname Test1 pathname ( pathname Volume pathname II …   How do I get it to stay as one variable?


What did the Origami Chicken and the Matchstick Man represent in "Blade Runner"?

In Blade Runner, Gaff is a rather dark, mysterious figure, who throughout the film, lays down 3 pieces origami - a paper chicken, a matchstick man, and a unicorn made of gum-wrappers. The unicorn is a subtle hint at Deckard being a replicant all along, but what did the other two represent?  Now, just to recap, Gaff puts down the chicken in the scene where Deckard refuses to help Bryant with the case. This makes partial sense to me, as Gaff was trying to imply Deckard was chickening out, although this seems very implausible. He puts down the matchstick man after Deckard investigates Leon's house. Deckard seems to gaze at it in confusion, or maybe even recognizance like he did with the unicorn.  I'm gonna make the bold claim that people are so invested into the unicorn that they easily ignore the two predecessors. What do these two creations in particular represent?  [FACT: Neither of these two origami was in the original script by Fancher and Peoples.]


In some paper, I need to quote a mathematician called López. So I used the command \'{o} in my .bib file, but when I compile with the style alpha, I get an accent \'{} on the 9 of the first year number. This gives L\'{9}2, instead of L\'{o}p92. What should I do to fix this?


Boy travels through time using a calculator

I read a book from the late 80's when I was 13 or 14 about a boy who travels through time using a calculator. I don't remember too much detail...but I do know that he was on the run from a bad guy who was chasing him and trying to take the calculator. The bad guy might have had a time traveling calculator as well because I remember him chasing him through time.  He got the calculator from a scientist and he was friends with the scientist's daughter. I know that both kids were teenagers, but I don't remember too much more than that.  I never got to finish the book...and for some odd reason, I really want to.


I linked objects with Ctrl+L. How can I now unlink a single object from the group with links? It used to be "U" in version before 2.8, I guess.


The zombies are supposed to drop a piece of paper named "Test" but it just screws up the whole zombie drop and not dropping anything at all.  Here is the part where the zombie is going to drop a named piece of paper:  {   "type": "minecraft:item",   "name": "minecraft:paper",   "functions": [     {     "function": "set_nbt",     "tag": "{display:{Name:"{\"text\":\"Test\"}"}}"     }   ] }   Is there something wrong with the code?


How do I request a package in the official Canonical maintained Ubuntu repos be upgraded?


sanitising form submitted data for mysql pdo query

Changing from php 5 to php 7 I must change my queries. Now using PDO. I connect to the db like this: $conn = new PDO("mysql:host=$hostname;dbname=$db", $username, $password);  my full query is 6 queries joined by union all. My (simplified) query is like this: $query="select * from table where sub_category like '%$input%'  where input is kettles, for example my script gets the input value like this: $input = $_GET['input'];  If I sanitise it using $input = $conn->quote($_GET['input']);  the value becomes 'kettles' (surrounded with single quotes), and my query returns 0 results. I process the query thus: $stmt = $conn->prepare($query); $stmt->execute(array("%$query%"));   $data = $stmt->fetchAll();  So; is PDO sanitising it and if not, how do I do it?


When we catch a falling object, where does its kinetic energy go?

Some of it is transformed into heat and noise, but where does the rest go?  Further details: The object does not bounce off (e.g. a sack of rice marble ball). The hand remains completely static throughout the process.


How do I check the status of the CMOS battery?

I have found myself in situtations where the internal battery has been used frequently. How do I check its status without diving into the mountain of directories?  NOTE I need to know about the CMOS battery. not the laptop's power supply, so this isn't a duplicate of those questions


Get start position of byte chunk from a byte array

Supposing I have a byte array of size 4096, what's an efficient way to get the start position of a chunk of say... 5 bytes that matches a pattern?  For e.g., I would like to get the start position of the 1st possible match of the byte array  var match = new byte[] { 0x03, 0x04, 0x05, 0x06, 0x07 };   So if the above chunk is found within my byte array, it will return me the position of the 1st byte (0x03)


How to set cellpadding and cellspacing in table with CSS?

Can someone tell me how to change table cellpadding and cellspacing like you can do it in html with:  <table cellspacing="0" cellpadding="0">    But how is it done with css?


I know it is used to summon things. But can the summoner only summon things that he own or is there a range within which it can summon anything or visualizing something that he doesn't own summons the thing.  Could Harry have 'Accio'ed the horcruxes had he tried?


I have a file like this:  1 2 3   I need to copy data n times with an empty line after each copy. I used these commands  #!/bin/sh num=$(sed -n '1 p' FILE.txt) for i in {1..  $num }; do cat distance_k.txt >> distance.txt; done   n is a number taken from another file 'FILE.txt' (FILE.txt have form like this :   90 Abcbaahjfh ...   However, it copied only 4 times. Could you please help me? Thank you so much!  bash shell  Output  1 2 3  1 2 3  1 2 3  1 2 3   1 2 3  ...


Remainder when dividing $13^{3530}$ with $12348$

Find the remainder when dividing $13^{3530}$ with $12348$.  How do I solve these type of exercises? I know there's some algorithm for solving them, I just haven't found a concrete example. Could anyone point me in the right direction?


How to get text from an element , when getText fails

I have the following element element(by.css("span[aria-label='Picker ID, TESTUSER']")  I want to assure the text on this filed is TESTUSER, so I tried:  expect(element(by.css("span[aria-label='Picker ID, TESTUSER']")).getAttribute('value')).toEqual('TESTUSER');  then I got the error: Expected null to equal 'TESTUSER' So I tried: element(by.css("span[aria-label='Picker ID, TESTUSER']")).getText().then(function (value) {         console.log(value);       })  And I got this error: Expected '' to be 'TESTUSER'.  How to get the value of this field and expect it is TESTUSER?


How to calculate the limit $\lim _{n\to \infty }\sum _{k=1}^n\sqrt{n^4+k}\sin(\frac{2k\pi }{n})$? Is it a Riemann sum?

I just came across this limit and I suppose it can be computed using a Riemann sum but I can't get it right. $$\lim _{n\to \infty }\sum _{k=1}^n\sqrt{n^4+k}\sin\left(\frac{2k\pi }{n}\right)$$ Any ideas?


How can I save a file to a specific "keyed" location?

In Finder to go to a specific location I can do Cmd-Shift-G  But what if I want to save to a specific location? That is, I don't want to click through a folder hierarchy in the save dialogue box.  For example I would like to save the current file to ~/.ssh    The Where drop down allows you to select a location, but I want to be able to enter the location using the keyboard.


Rank of the sum of an all-ones matrix and an identity matrix

Let $B$ be an all-ones matrix of dimension $n \times n$, and $I$ be the identity matrix of dimension $n \times n$. Define $A = \frac{1}{n}B - I$. For $n=3$, $A$ would yield  \begin{equation*} \begin{bmatrix} -2/3 & 1/3  & 1/3  \\ 1/3  & -2/3 & 1/3 \\ 1/3  & 1/3 & -2/3 \end{bmatrix}. \end{equation*}  How would one compute rank$(A)$ for any $n$?  I have noted that any row $r_i$ of $A$ can be written as a linear combination of the other $n-1$ rows. Specifically, $r_i = - \sum_{j\neq i} r_j$. This implies rank$(A) < n$, but I don’t know how to compute the exact rank of $A$.   Any hint would be appreciated.


I am creating a bash script which read the Txt file and with While Loop and then do some tricks with SED to get the string out it and the Value of string needs to be hold into another Varibale.  Here is my Script.  while read p; do PATH="$p | sed -r 's|.*media/([^/]+).*|\1|'" #FILE = "$p | awk -F"/" '{print $4}'" echo $PATH #echo $FILE #echo $p done < /tmp/list.txt   List.txt  cap/media/101/101.mp4 cap/media/102/102.mp4 cap/media/103/103.mp4 cap/media/104/104.mp4 cap/media/105/105.mp4 cap/media/106/106.mp4    thank you


Suppose that you have a group of items and you make a hierarchy structure for them. Now, you call this structure, "item hierarchy" or "items hierarchy"?  However, my real phrase is "context hierarchy" vs. "contexts hierarchy"  In general there are some noun-noun constructions which address a group of things. Then the first noun is plural or singular?


Generalizing concept of content of a polynomial to commutative rings

Let $A $ be a commutative ring with identity. Let $f,g\in A [x] $. Let $I_1,I_2, J $ be the ideals generated by the coefficients of $f,g,fg $ respectively. Must $J $ be equal to $I_1 I_2$ ?  It is an exercise an Atiyah and Macdonald to show that this true in the case  $I_1=I_2=A $.  Thank you


Can someone assist me with this doubt? In many sites I have seen it written as "IP's" and in other as "IPs". What is the correct form to refer for the plural of IP?


I added this to ~/.bashrc to provide colorized tail:  tailc () {   tail $@ | ccze }   And I can run it as so: tailc -f -n 10 foo/log.txt  But I can't use it on a privileged file:  sudo tailc -f -n 10 /var/log/syslog   Error:     bash: tailc: command not found   I know I can do it like this: sudo bash -i -c '...' but I want to know if I can run it without that more complicated syntax. What can I do to be able to just type sudo tailc ...?  BTW, I added that function to /root/.bashrc as well, but that didn't help either.


Is there any side effect to compile production code with gcc debug options?

For gcc flags like --coverage, do they have any side effect, for example run time performance penalty?  If not then can I just leave them in the common makefile and use them to build production code?  Gcc document doesn't say anything about this.  This question    explains -g, but how about --coverage？I guess the answer is yes, the added instrument code must cost quite a bit at runtime


Xcode undefined symbol error when deleting unrelated code C++

I have a simple function declared in header file and defined cpp file. When I delete the test_vector function in cpp file, I got this error. Undefined symbols for architecture x86_64:   "void chapter3::print_vector<int>(std::__1::vector<int, std::__1::allocator<int> > const&)",  referenced from:       _main in main.o ld: symbol(s) not found for architecture x86_64   What's going on here? //  chapter3.hpp   #ifndef chapter3_hpp #define chapter3_hpp  #include <stdio.h> #include <vector>  namespace chapter3 {  template<typename T> void print_vector(const std::vector<T>&);  }  #endif /* chapter3_hpp */   //  chapter3.cpp  #include "chapter3.hpp" #include <iostream> #include <vector>  using namespace std;  namespace chapter3 {  template<typename T> void print_vector(const vector<T>& vec) {     for(auto& elem: vec) {         cout << elem << ' ';     }     cout << endl; }  void test_vector() {     vector<int> u(10, -1);     print_vector(u); }  }   //  main.cpp  #include <iostream> #include <vector>  #include "chapter3.hpp"  using namespace std;  int main(int argc, const char * argv[]) {     vector<int> vec {1,2,3};     chapter3::print_vector(vec);          return 0; }


lstlistoflistings entry in table of contents name is always 'Contents'

I'm trying to add a list of code listings to my document, with a reference to it in the TOC. By simply calling  \lstlistoflistings   I end up getting everything I need (the list of listings, an entry in the TOC, etc) EXCEPT for the fact that the entry is always named 'Contents'. I was able to change the title of the listing page itself by running the command   \renewcommand\lstlistlistingname{List of Code}   but this doesn't change the reference in the table of contents.  EDIT: Adding a minimal working example  \documentclass{Thesis}  \usepackage{listings}  \begin{document} \renewcommand\lstlistlistingname{List of Code}  \tableofcontents  \lstlistoflistings  \lstset{caption=Some Code} \begin{lstlisting} Some code \end{lstlisting} \end{document}


Why is the bolded text disappearing in chat?

The original message was:     Right now, I think that this chatroom should be for deciding what we're going to do in the next event, if it ever happens.   And yet, the bold text disappeared. Why?


Achievements dropdown is broken on SE.com

When going to any page of  with a new reputation gain, the achievements dropdown keeps showing a new badge green highlight:    And then trying to dismiss the notification by clicking on it gets rid of the green badge notification, but the +5 remains even after I've clicked away from the dropdown.


how to install phpmyadmin in Ubuntu server 18.04.1 LTS Bionic?

i created this question because i cant install phpmyadmin in Ubuntu 18.04 bionic LTS.  i use  sudo apt-get update sudo apt-get upgrade sudo apt-get install phpmyadmin   And get "unable to locate package"  I search the package in package.ubuntu.com  And add to sources.list this repository:  mirrors.kernel.org/ubuntu   Now appear a error from depencies.  php-mbstring php-common   later when try install these, appear:  php7.2-mbstring php7.2-common   And later:  0.7.2ubuntu-0 (something like this)   How can i install phpmyadmin?  I do this  sudo apt-get update   all packages are updated     sudo apt-get upgrade   0 updated, 0 new will by installed, 0 for delete and 0 not updated  sudo apt-get install phpmyadmin   reading package list... done creating three of dependencies reading state information... done E: cannot locate package phpmyadmin


I have a script which calls two commands:  long_running_command | print_progress   The long_running_command prints progress but I'm unhappy with it. I'm using print_progress to make it nicer (namely, I print the progress in a single line).  The problem: Connection a pipe to stdout also activates a 4K buffer, so the nice print program gets nothing ... nothing ... nothing ... a whole lot ... :)  How can I disable the 4K buffer for the long_running_command (no, I do not have the source)?


What prevents me from just editing the /etc/shadow file in unencrypted systems?

Real dumb question, but suppose a computer with Linux does not have an encrypted hard drive. If I generated a hash with "openssl passwd", couldn't I just run a live version of Ubuntu and add my hash to the /etc/shadow file? Or is /etc/shadow encrypted even if the hard drive isn't?


How do I obtain my dead husband's password for his iPhone?

My husband died.  I have the death certificate.  Also using his iPhone.  Don't have his password.  Would like to obtain it.  How do I do that?


When "exactly" is the Yearling badge awarded?

I just noticed that I've been a member for 1 year and 2+ days. I hovered over the 1 year text to see the date. I have exactly 200 rep.  I found multiple questions about the Yearling badge not being awarded, but the users hadn't quite reached the 1 year mark yet.  I thought maybe I needed more than 200 rep, but the badge description says at least 200.  So perhaps the association bonus doesn't count? Or perhaps the description is incorrect and should read more than 200. Or perhaps the badges aren't awarded in real time and I have to wait for some scheduled calculation?   says that rep > 200 is required. However,  says rep >= 200 is required. And  says the association bonus does count, but rep > 200 is required. A comment on  says the calculation is done nightly.  Just curious. Why haven't I received my Yearling badge for meta? If I need more than 200, the description should be corrected. And does that mean I have to wait another whole year?  Updated  If we consider the comment by Sha Wiz Dow Ard and take the definition of earn literally, we didn't earn our first rep point. But that is misleading because what about rep that you earned and then gave away as a bounty (or lost by other means)? You still earned it.  For reference, this is the description at time of writing.     Active member for a year, earning at least 200 reputation    It seems that it is calculated on how much you have and not how much you earned. So you need to have rep > 200. And thus, it should be explained that way.  I think the description on the  and the description in  should be updated. I know I can edit the answer, but while I now have anecdotal evidence, I am still not exactly sure how the calculation is done behind the scenes.  For reference, the wiki answer has this description at time of writing.     Have a reputation ≥ (number of years as an active user) × 200


What stops gradient descent from finding the largest error?

If a gradient points towards a max or a min what stops gradient descent from maximizing error instead of minimizing it?  Is it the nature of the update step that makes this process one way?


Is there just one exponential family? Or are there many exponential families?

I'm confused by the phrasing I've seen about exponential families.  What does it mean to say "an" exponential family.  Why not "the" exponential family?  From a pdf from Berkely: "we define an exponential family of probability distributions as those distributions..."  From Statistical Inference (George Casella, Roger L. Berger): "Let $X_1, X_2, ..., X_n$ be iid observations from a pdf $f(x|\theta)$ that belongs to an exponential family..."  I've also ready things that say, "this distribution belongs to an exponential family..."  But what are the different exponential families? Why not just say the exponential family? If there are multiple exponential families, why haven't I ever seen something like, "the binomial distribution belongs to exponential family A, while this other distribution belongs to family B..."?   I've searched around, and can't find a list of these families. How can there be an exponential family if there are not more than one of them?


Let me know I have upvotes even after hitting the rep cap

When you cap, you don't see any upvotes you get on your profile, therefore, you don't have any update on how your questions / answers are doing unless you look at them manually.   Capping the 200 daily rep is not a reason to stop posting here so could I get notified somehow that my posts are being voted on ? Maybe put a little +X in a different color letting me know that I got these votes but I won't get the reputation for it.   I can go and see in my reputation feed inside my profile and see it :    So I don't see why it wouldn't show up in the feed above.  Maybe putting the feed button green without any +X just like when you aquire a badge.


I read the following sentence in a book. I am confused about the sentence structure.  "She thought she would have survived her first term had she kept good relations with the army though"  Here "had she" confuses me. Can anyone kindly explain the sentence structure and the use of "had she"?  Can i write it like "if she had instead of had she"?  For example   "She thought she would have survived her first term if she had kept good relations with the army though"  Thanks in advance.


I have an open source application that i can edit any files on it. Now i want to edit some pictures that have no Extension! (Just the picture name can shown). and when i open them with any Picture-Editors (like Paint, Ashampoo, GIMP), it says "Unknown Extension.". but i have to Edit this non-Extension picture My Question: How can i Edit an non-extension picture file?


Making nonoverlapping service area polygons using QNEAT3; service area polygon errors

I am doing a project in which I am determining which areas of New York City can be accessed within a five- or ten-minute walk of a subway entrance. I have done this in the past in ArcGIS, and am trying it out in QGIS. The goal of the project is to determine which areas of the city would become accessible within a five- or ten-minute walk if closed subway entrances, of which I have accumulated a list , were reopened. I used the  tool to first look at the service areas for open subway entrances, based on the city's . In ArcGIS, I could create non-overlapping service area polygons to allocate areas to the closest subway entrance. I have not seen any way of doing this in QGIS. When using QNEAT3, all the areas within, for example, five minutes of an entrance, are in a single layer, which is not very helpful, as can be seen in this screenshot below.  For some reason, the polygons for areas within a closer range of an entrance, i.e. 60-120 seconds, are sometimes in the incorrect spot, being underneath layers like the 300-480 second polygon layer. If you compare the two images below, you will see that if I uncheck this layer, the 60-120 second layer is visible. In ArcGIS, I had no issues with this at all. How do I remedy this?   Another issue is that there are spikes in the polygons, especially those in the 480-540 and 540-600 second layers, which should not be there. These areas are clearly not within ten minutes of an open subway entrance. I have no idea what error is causing them. Does anyone have an idea? Here is an overview showing multiple errors:  This major one occurs over a body of water:   This one for some reason has a polygon connecting Lower Manhattan with Brooklyn over New York Harbor.   You also have a big one here in Queens.


Visa requirements for Filipino traveling to Costa Rica via South Korea and USA

I'm from Philippines and planning to visit Costa Rica.  Do I need a transit visa to go through Dallas Texas.   Airlines: Philippines and American. Departing: Manila Philippines. Arriving: San Jose Costa Rica,   Route: Manila - Seoul, Seoul - Dallas Texas, Dallas Texas. - Costa Rica.  I just have my Passport, a plane ticket and a letter of invitation.


Hi i have a problem with a trigonomic excercise about tan

How can i solve this?  the exercise is:     $$\tan{20^{\circ}}\cdot\tan{40^{\circ}}\cdot\tan80^{\circ}$$     I  have to define the exact answer. I have no idea how to start this exercise so please help. I think that would be so easy if I just multiply them. Thank for your help.


Estimating same model over multiple time series

I have a novice background in time series (some ARIMA estimation/forecasting) and am facing a problem I don't fully understand.  Any help would be greatly appreciated.  I am analyzing multiple time series, all over the same time interval and all of the same frequency, all describing a similar type of data. Each series is just one variable, there are no other corresponding predictors that I'm looking at.   I have been asked to estimate a single model that describes ALL the series - for example, imagine I could find one ARIMA (p,d,q) with the same orders, coefficients, etc. that could fit all the series.  My supervisor does not want me to separately estimate each series, nor does he want me to do some sort of VAR model with dependencies between the series.  My question is:  what would I even call such a model, and how might I go about estimating / forecasting it?  If it's easier for you to use code examples, I speak both SAS and R.


Evaluate the integral using the theory of residues: $\int_{-\infty}^{\infty} \frac{dx}{(x^2+1)^2(x^2+16)}$

$$\int_{-\infty}^{\infty} \frac{dx}{(x^2+1)^2(x^2+16)}$$  My attempt:  We are integrating over the real axis, which is the real part of a set of complex numbers, so $$=\int_{-\infty}^{\infty} \frac{dz}{(z^2+1)^2(z^2+16)}$$  $$=\int_{-\infty}^{\infty} \frac{dz}{((z+i)(z-i))^2(z+4i)(z-4i)}$$  But I notice that all of the singularities are imaginary! Should this give me pause? What should I do now?


I think adding a way to approve/reject low-reputation users' images would be a nice addition to the StackOverflow feature set.  Right now, when attaching images for a low-rep user, I have to edit the question, copy the URL to a new tab, make sure it's not spam, and attach the image.  Maybe allowing new users to normally link an image but giving an orange flag box saying Your image will be hidden until approved?    A typical scenario:


Good book for learning about mathematical foundation of quantum physics

I've been trying to slog through Quantum Physics for Dummies, but can't even get past the first chapter.  There's a lot of talk of Bras, Kets, and Hilbert spaces, but I feel I'm missing the mathematical underpinnings that would make it understandable.  Can anyone recommend a good book to build up my mathematical foundation for quantum physics?  A textbook or study guide would be fine - I'd want a lot of examples and practice problems.  By the end of this venture, I'd like these concepts to be intuitive to me.


What University Affiliation should I list on my paper?

I wrote a paper with my colleagues at my alma mater, fresh graduated from my undergraduate degree. At that time I had no University Affiliation. Now I'm studying a Masters in ANOTHER university, should I put this new Institution as my Affiliation? or none?


How to process click event of dynamically created hyperlinks?

I have dynamically generated links like   Details  When one of them clicked I want to process this event with javascript code like this  $(document).ready(function () {     var a = document.getElementsByName('details').item(0);      a.on('click', function () {         $.ajax({             ///         });     }); });   However, even though it seems to find hyperlinks quite perfectly, on click event it doesn't enter the function.  What is wrong with the implementation?


Today one of my friends asked  me what's the $$\int \log x \,\, \mathrm{d}x$$ and I was unable to answer. I think we just take the Taylor series and integrate it . Is that all or something else.   Note: I am grade $11$ student so I don't know any advanced calculus and all hyperbolic functions.


How to avoid having 10 switch cases in java?

I am trying to minimise below 10 switch case but after trying few times I am not able to. Can somebody suggest what should I do?  Thanks in advance.   private int getCode(String digit) {      int keycode = 0;      switch (digit) {         case "0":             keycode = AndroidKeyCode.KEYCODE_0;         break;          case "1":             keycode = AndroidKeyCode.KEYCODE_1;         break;          case "2":             keycode = AndroidKeyCode.KEYCODE_2;         break;          case "3":             keycode = AndroidKeyCode.KEYCODE_3;         break;     }      return keycode; }   Thanks


NoSuchMethodError in jasper report after importing a jar file

I have added a jar file to add a chart customizer class in my jasper report. But when compiling it gives the NoSuchMethodError. I have added enough libraries to the classpath and I am using jasperreports-6.5.1 and jfreechart-1.5.0.   Jasper exception:  java.lang.NoSuchMethodError: org.jfree.chart.title.LegendTitle.setItemLabelPadding(Lorg/jfree/chart/ui/RectangleInsets;)V null  java.lang.NoSuchMethodError: org.jfree.chart.title.LegendTitle.setItemLabelPadding(Lorg/jfree/chart/ui/RectangleInsets;)V   Source code in the jar file:  public class ChartCustomizer extends JRAbstractChartCustomizer { DecimalFormat twoPlaces = new DecimalFormat("0.00");  @Override public void customize(JFreeChart jFreeChart, JRChart jrChart) {     if (jFreeChart.getPlot().getClass().equals(PiePlot3D.class)) {         formatPiePlot3D((PiePlot3D) jFreeChart.getPlot());                 } else if (jFreeChart.getPlot().getClass().equals(PiePlot.class)) {         formatPiePlot((PiePlot) jFreeChart.getPlot());     }     LegendTitle legend = jFreeChart.getLegend();     legend.setItemLabelPadding(new RectangleInsets(2, 2, 2, 999999999)); }  private void formatPiePlot3D(PiePlot3D plot) {     PieSectionLabelGenerator labelGenerator = new StandardPieSectionLabelGenerator("{2}", new DecimalFormat("0"), new DecimalFormat("0.00%"));     PieSectionLabelGenerator legendGenerator = new StandardPieSectionLabelGenerator("{0} - {1}", new DecimalFormat("#,##0.00", new DecimalFormatSymbols(new Locale("en_US"))), new DecimalFormat("0%"));     plot.setLegendLabelGenerator(legendGenerator);     plot.setLabelGenerator(labelGenerator); }  private void formatPiePlot(PiePlot plot) {     PieSectionLabelGenerator labelGenerator = new StandardPieSectionLabelGenerator("{2}", new DecimalFormat("0"), new DecimalFormat("0.00%"));     PieSectionLabelGenerator legendGenerator = new StandardPieSectionLabelGenerator("{0} - {1}", new DecimalFormat("#,##0.00", new DecimalFormatSymbols(new Locale("en_US"))), new DecimalFormat("0%"));     plot.setLegendLabelGenerator(legendGenerator);     plot.setLabelGenerator(labelGenerator); }    }  Libraries imported to the jar file source and classpath:   jcommon-1.0.24   jfreechart-1.5.0   jasperreports-6.5.1   jfreesvg-3.3   The method exists in jfreechart-1.5.0 library


How do you view the bottom of really tall cells in Excel?

When there are very tall cells in Microsoft Excel, trying to scroll via mouse or even via scrollbar (clicking on "<-" "->" pointers) just jumps below to the next cell, hiding the bottom content of the large cell in question.   Is there an option to have Excel scroll smoothly?  So far I found only one way - click middle button on mouse - and scroll smoothly by moving mouse aside.


Counting necklaces with a fixed number of each bead

I want to count the number of necklaces, with $n$ beads in total, where the alphabet of beads is $\{1,\ldots,k\}$, and where the number of beads with color $i$ is $n_i$. For example, if $n=4$, and $n_1 = n_2 = 2$, the following necklaces are the only possible $$1122$$ $$1212$$  I have been able to find formulas for different variations of the problem, but not this one. If there is no nice formula, a generating function is always a nice compromise.


If $p$ is congruent to $2 \pmod 3$, how can I prove that all $a$, $1 \le a \le p-1$ are cubic residues $\mod p$?  Here's what I've done:  $1^3$ congruent to $1 \pmod p$ thus, 1 is a cubic residue, Also $(p-1)^3=(p-1) \pmod p$ implies  $$(p-1)^3 - (p-1) = (p-1)[(p-1)^2 -1] = (p-1)(p^2 -2p) = p(p-1)(p-2) $$ implies $$p|(p-1)^3 -(p-1)$$ Thus  $p-1$ is a cubic residue $\mod p$. Now I don't know how to show for $1\lt a \lt p-1$ are all cubic residues when $p$ is congruent to $2\pmod 3$.


Trouble installing HTML Tidy 5.4.0 on Xenial

This pre-existing question on askubuntu.com purports to solve the problem of installing the reboot of HTML Tidy: . However, when I followed the accepted answer's instructions on Xenial 16.04.2, I encountered a problem that was not covered there, so am creating a new question.  I do the following:  wget https://github.com/htacg/tidy-html5/releases/download/5.4.0/tidy-5.4.0-64bit.deb sudo dpkg -i tidy-5.4.0-64bit.deb   and get this error:  dpkg: error processing archive tidy-5.4.0-64bit.deb (--install): trying to overwrite '/usr/lib/libtidy.so', which is also in package libtidy-0.99.0 2009 1223cvs-1.5   I do not already have the older tidy package installed, but I went through the motions of uninstalling it anyway:  sudo apt-get -y autoremove tidy Package 'tidy' is not installed, so not removed   No change in ability to install tidy 5.4.0 afterwards, or the error message that ensues.   Here is the result of apt-cache policy:  apt-cache policy libtidy-0.99-0 libtidy-0.99-0:   Installed: 20091223cvs-1.5   Candidate: 20091223cvs-1.5   Version table:   *** 20091223cvs-1.5 500   500 http://archive.ubuntu.com/ubuntu xenial/main amd64 Packages   100 /var/lib/dpkg/status


Is there a command that automatically kills players who use specific commands?

I want to prevent my friends from using the commands /give and /gamemode, however I wish to allow them to use commands such as /tp. How could I prevent them from using these commands, without turning the allow cheats option off?


usr/sbin/grub-probe error:failed to get canonical path of '/cow after ubuntu 16.04 update

After I update the ubuntu version from 14.04 to 16.04 system not booting. screen sowing   grub>   Then I tried to update the grub as follows, 1/ boot the system using USB boot. 2. open the terminal and type   sudo update-grub   it throws the below error message.  /usr/sbin/grub-probe:error:failed to get canonical path of '/cow'.   Googled and tried many forum answers. But could not solved.  Greatly appreciated your help.


I have made some modification to my prompt with use of colors via tput.  It looks like now when I try to do an arrow up lookup after few moves up, the prompt is being cut into half, what I mean by this is:  From this:  PROD mysuer@server1.domain.com:~$ vim .bashrc   To this:  PROD mysuer@servegit rebase origin/add_pool   ctrl + c brings everything back to normal.  I have found some posts indicating that this may be due to the issue with missing escapes for [ however I don't see an issue here:  My code:  #red for prod, green for lab  COLOUR_RESET=$(tput sgr0) COLOUR_GREEN=$(tput setaf 2) COLOUR_BLUE=$(tput setaf 6) COLOUR_YELLOW=$(tput setaf 3) COLOUR_RED=$(tput setaf 1) BOLD=$(tput bold)  if [[ $HOSTNAME =~ .*\.domain.com$ ]]; then   COLOUR=$COLOUR_RED   PROMPT_TEXT="PROD" fi  if [[ $HOSTNAME =~ .*\.lab$ ]]; then   COLOUR=$COLOUR_BLUE   PROMPT_TEXT="LAB" fi   MYPROMPT="$COLOUR$BOLD$PROMPT_TEXT$COLOUR_RESET \[\u@$COLOUR$BOLD$(hostname -f)$COLOUR_RESET:\w\]\$ "  PS1=$MYPROMPT   UPDATE: @KamilMaciorowski has pointed out a similar question although it was not relating to a tput colors.


If $G$ solvable and $f$ a surjective homomorphism between $G,G'$, then $G'$ is solvable

Let $G$ be a solvable group, $f: G \rightarrow G'$ a surjective homomorphism. I need to show that $G'$ is solvable.  Let $G$ be solvable. Then there exists a sequence of subgroups $$\{e\}=H_r\triangleleft H_{r-1}\triangleleft\cdots \triangleleft H_{1}\triangleleft H_0=G$$ such that $H_{i+1}\triangleleft H_i$ for all $i=0,1,...,r-1, $ and such that $H_i/H_{i+1} $ is abelian.  We know that $f(H_i)\triangleleft f(G)$, but since $f$ is surjective, $f(H_i)\triangleleft G', \forall i=0,1,...,r-1.$ Also, $f(H_i)\subset f(H_{i-1}),\, $thus $f(H_i)\triangleleft f(H_{i-1}), \forall i=0,1,...,r-1.$ Thus we get $$\{e\}=f(H_r) \triangleleft f(H_{r-1})\triangleleft  \cdots \triangleleft f(H_1)\triangleleft f(H_0=G)=G'.$$ It remains to be shown that $f(H_i)/f(H_{i+1})$ is abelian.   Here I can not go further. I need a solution proposal or some hint. Thanks.


How do I find a previously discovered system?

Long story short, I rushed a few jumps early in the game to finish a story mission. I then wanted to go back to a planet that was very rich in resources and whatnot, but I was unable. I didn't find a way to set a waypoint or anything similar from the discoveries page, and trying to point and click in the star map is almost impossible.  Is there an easy way to go back to a system that you've already discovered?


At the maximum 200 rep/day, are down votes deducted from uncredits or taken from the 200?

If I have reached the 200 per day reputation point, and have not had 50, or whatever, reps added - are any downvotes then deducted from my stated reputation or do they deduct from my 'unpaid' credits ?


how to remove windows if already combined with ubuntu

I installed ubuntu next to windows how would I go about getting windows removed without deleting my ubuntu?


I have been successful in using the GeoServer API to create workspaces and data sources, but I believe the documentation is quite buggy, since I cannot use the "roles" endpoint, for reference:  I looked at:  so it appears I'm not the only one with this issue. When I call either GET to /roles or /security/roles I simply get: statusCode: 200    <title> Geoserver Configuration API </title> <meta name="ROBOTS" content="NOINDEX, NOFOLLOW"/>
Geoserver Configuration API

workspaces

namespaces

styles

layers

layergroups

reload

reset

about/manifest

about/version

about/status

settings

settings/contact

services/wms/settings

    I've tried sending an email to the email listed on the api documentation page but received a "returned to sender". We are using geoserver 2.11.1


airplane mode is switching on off continuously (18.04)

I have updated ubuntu from 16.04 to 18.04. The system has worked properly for one day.  After that it started to switching between airplane ✈ mode on and off continuously.


Minors holding dual citizenship - using Canadian passport to enter/exit US

My husband and two daughters, ages two and six, are all dual American/Canadian citizens.  We are traveling to England in less than two weeks.   I am kicking myself because I realized today that my six-year-old’s US passport just expired, and I don’t think it will be possible for me to renew it before we travel on August 18th. However, her Canadian passport is still valid. Will this be a problem when it comes time to return to the US from England after our 10 day trip?   My husband and two-year-old daughter will each carry both of their passports, and I will only carry my American one since that is all I have. We can also bring my six-year-old’s birth certificate if that will help.   We have never traveled outside of the US and Canada as a family together, so this is new to me. Part of me feels like how could they possibly give us trouble or not let us back into the US when we all have valid passports, one of them will just happen to be Canadian, but Canadians are allowed into America, especially when they are six years old and both of their parents are American!   However, I don’t want to assume anything, but since our situation is somewhat unique, I don’t really know who to ask for help. Does anybody foresee a problem with this? I can also bring her expired US passport just to further document the situation.  I am so angry at myself for letting her US passport expire, and not even thinking about it until right before our trip! I’m really hoping that I’m worried over nothing, since a Canadian passport is a legitimate travel document, but I just don’t want any trouble at customs or immigration.  TLDR: Can a 6 year old duel American/Canadian citizen travel out of and back to the US on their Canadian passport if their US passport has expired?


OCT configuration of Outlook 2013 with Exchange 2013

We have Outlook 2013 configured using the Office Customization Tool (setup.exe /admin) that is built into Office 2013 enterprise.  This configuration worked great with Exchange 2007 but just fixing the server address in the configuration results in Outlook 2013 saying that it cannot communicate with the server followed by the OCT file not being correct.  If we do not configure the OCT settings, it runs through the Welcome wizard and auto configures correctly.  How can I fix the OCT config to make the profile without asking questions?  This is the original post  that I wanted to ask clarification on because the answer doesn't tell you how to fix the problem.  It was deleted by server fault moderators because it doesn't "answer the question". I was told that what comments are for, but I don't have enough rep to comment.  Not a great way to encourage new users to your forum...


"Delete this answered question?" when the only answer is deleted

Looks like there's a small bug in the UI: I posted a question here on meta.SE which ended up being just something dumb I was doing and no use to anyone in the future. At first I posted an answer saying what the dumb thing was, but then I realized that the whole thing had no value, so I deleted the answer, and then deleted the question — whereupon it asked me:  Delete this answered question? We do not recommend deleting questions with answers because doing so deprives future readers of this knowledge. Repeated deletion of answered questions can result in your account being blocked from asking. Are you sure you wish to delete?  (Screenshot below) Probably shouldn't ask (or add to the tally) if the only answers are deleted ones...


I'm trying to insert a C++ code inside a LaTeX document. As in the object, I'm trying to use accent vowels, but I'm not able to add them especially in the comment section. Here's main.tex: \documentclass[a4paper, 12pt, italian]{article} \usepackage[italian]{babel} \selectlanguage{italian} \usepackage[T1]{fontenc} \usepackage[utf8]{inputenc} \usepackage{listings} \usepackage{xcolor}  \definecolor{codegreen}{rgb}{0,0.6,0} \definecolor{codegray}{rgb}{0.5,0.5,0.5} \definecolor{codepurple}{rgb}{0.58,0,0.82} \definecolor{backcolour}{rgb}{0.95,0.95,0.92}  \lstdefinestyle{mystyle}{     backgroundcolor=\color{backcolour},        commentstyle=\color{codegreen},     keywordstyle=\color{magenta},     numberstyle=\tiny\color{codegray},     stringstyle=\color{codepurple},     basicstyle=\ttfamily\footnotesize,     breakatwhitespace=false,              breaklines=true,                      captionpos=b,                         keepspaces=true,                      numbers=left,                         numbersep=5pt,                       showspaces=false,                     showstringspaces=false,     showtabs=false,                       tabsize=2 }  \lstset{style=mystyle}  \title{Casi d'uso: Prove Induttive} \author{Luca Polese} \date{December 2020}  \begin{document}  \maketitle  \section{Prime Prove Induttive} \subsection{Casi semplici} Esempio:  \lstinputlisting[language= C++]{prova1.cpp} \end{document}  Here is prova1.cpp: /**  * Questo esempio deve considerare il caso in cui la lista   * sia già vuota in partenza.  * Lo stessa varrebbe se cominciassi con un array pieno e mi   * ritrovassi ad un certo punto con un array vuoto, poichè    * la ricerca è fallita  */   //PRE: (dim>=0, A[0...dim-1] è definito) bool presente(int*A, int dim, int z){     ... } //POST: (restituisce true sse A[0...dim-1] contiene z)  I'm using OverLeaf and the result is something like this:  As you can see, all the accented vowels are missing. I hope you can help me Thanks in advice.


Can I replace an 1100 mAh battery with a 1500mAh one?

I've got a Canon EOS camera that takes a BP-511 battery.  The specs on the battery are 7.4V and 1100mAh.  The battery is dead and I want to buy a replacement, but I'm looking at a third party battery, because it's much cheaper than the Canon branded one.  I've found one with very high reviews online, and it seems identical except that it's rated at 1500mAh instead of 1100mAh.  So the question is: is this difference important to the camera or not?


Prove that for integers $a,b$ number : $(a+\frac{1}{2})^n+(b+\frac{1}{2})^n$ is integer for finitely many integers $n$.   I tried to use Binomial theorem but I didn't find any interesting.


Getting not defined error while running code

I am writing code for my deep learning project and when getting error while running facial detection.  I am building facial recognition system and I am getting error      NameError: name 'x' is not defined    while running the code, but I am not able to find root source of these problem.  import numpy as np import cv2  CascadeClassifier = cv2.CascadeClassifier(r'C:\Users\ESEC\Desktop\opencv\aditya\cascades\haarcascades\haarcascade_frontalface_alt2.xml')  cap = cv2.VideoCapture(0)   while(True):     # Capture frame-by-frame     ret, frame = cap.read()        gray = cv2.cvtColor(frame, cv2.COLOR_BGR2GRAY)      faces = CascadeClassifier.detectMultiScale(gray, scaleFactor=1.5, minNeighbors=5)      for (x, y, w, h) in faces:         print(x,y,w,h)         roi_gray = gray[y:y+h, x:x+w]          roi_color = gray[y:y+h, x:x+w]          img_item = 'image.png'         cv2.imwrite(img_item, roi_gray)     # Our operations on the frame come here      color = (255,0,0) #BGR 0=255      stroke = 2       end_cord_x = x + w      end_cord_y = y + h      cv2.rectangle(frame, (x, y), (end_cord_x, end_cord_y), color, stroke)      # Display the resulting frame     cv2.imshow('frame',frame)     if cv2.waitKey(20) & 0xFF == ord('q'):         break       # When everything done, release the capture      cap.release()      cv2.destroyAllWindows()   It should be running smoothly and should be showing rectangle around the face but I am getting this following error.  File "camera-test.py", line 34, in <module> end_cord_x = x + w NameError: name 'x' is not defined


How is the following differential equation solved?

The equation is the following:  $$ {d^2 x(t) \over dt^2} = {k \over (x(t))^2} .$$ I used the software Maple to try and solve it, it can't. I did some research and this equation is obviously second order, and maybe of type "missing x", even if I don't know what that really means. I also found this substitution: $$ v = {d x(t) \over dt} $$ but nothing really came out of it. Also, none of my teachers are able to solve it, I have asked three of them. This equation comes the Newton's law of gravitation.


Sequence generated by arithmetic and harmonic mean converges to square root

I need to show the following:     Starting with a point $S=(a,b)$ of the plane with $a>b>0$, we generate a sequence of points $(x_n,y_n)$ according to the rule: $$x_0=a, y_0=b, x_{n+1}=\frac{x_n+y_n}{2}, y_{n+1}=\frac{2x_ny_n}{x_n+y_n}.$$ Prove that $\lim x_n=\lim y_n=\sqrt{ab}$.   I can show that $x_ny_n=ab$ and $x_n>y_n$ for all $n$, but I am having trouble proving $\lim x_n=\lim y_n=\sqrt{ab}$. Suggestions?


The Meta is being both discussion and not a discussion site

At the beginning of the tour we see:     Meta Stack Exchange is a question and answer site for meta-discussion of the Stack Exchange family of Q&A websites.   Fine. Then we look a bit further...     The guidance on all our Q&A sites explicitly disallows meta-discussion, to reduce clutter and noise. There's no chit-chat; just questions and answers.     In this case it sounds like the rule which applies to MSE also, which would  not be correct. Sometimes it's about fixing bugs or implementing feature requests, etc.   And:     This site is all about getting answers. It's not a discussion forum. There's no chit-chat.   Yeah, not a forum, no chit-chat... Though as it's the Meta, it's a discussions site. Probably it should be reword a bit, needs more meta.


Complex Equation Of a Circle $|z-z_1|^2+|z-z_2|^2=k$.

If $z_1$ and $z_2$ are fixed and satisfies $|z-z_1|^2+|z-z_2|^2=k$   what are the possible values of k so that this equation represents a   circle?   I tried using pythagoras theorem,that the equation of circle should be $z-z_1|^2+|z-z_2|^2=|z_1-z_2|^2$.  So k should be $|z_1-z_2|^2$.But the answer is given is $k>\frac{1}{2}|z_1-z_2|^2$.Where am I going wrong?How to approach the problem (preferably geometrically) ?


Do I need a Transit Visa for layover at London Heathrow Airport?

My wife has a Visitor Visa for Canada and daughter has Study Permit for Canada which is valid more than six months from the date they are travelling.  They have a layover at London for 6 hours which does not cross the day meaning day of landing and boarding the next flight is on the same day.  So, do they require a Transit Visa? I have already gone through the  to check the same but I could not understand last question which says ask your airline whether you need to pass the border control.


I want to make a script in Python that has to do some relatively simple calculation. I noticed that some very simple additions like 1.3+0.13 yield strange results (1.4300000000000002 for this example). Is this a known issue? Is there a way to avoid it? To test it by yourself: print (1.3+0.13)


US news articles missing out "on" when referring to a day

When watching US television news or reading US news articles there is this affectation where instead of saying:     "Spotify music-streaming service to launch in U.S. on Thursday" ()   or      "Leading credit rating agency Moody's said on Wednesday that the U.S. government's impeccable credit..." ()   The on preposition is missed out.  Is this just a peculiar US journalistic "news speak" shortcut or do American non-journalist writers write this way too?


I have a matrix which is kind of symmetrical with the other diagonal, i.e., something like  $$A = \left[ \begin{array}{c c c c}    a & b & c & d \\    e & f & g & c \\    h & i & f & b \\    j & h & e & a  \end{array} \right]$$  Does this matrix have a special name in literature? What are it's properties?  And a matrix that is symmetrical by both diagonals   $$A = \left[ \begin{array}{c c c c}    a & b & c & d \\    b & e & f & c \\    c & f & e & b \\    d & c & b & a  \end{array} \right]$$  What's the name of it? Any interesting properties?


Is "from where" grammatically equivalent to "from which"?

The following is an excerpt from a New York Times article of April 6.     “Tonight, I ordered a targeted military strike on the air base in Syria from where the chemical attack was launched,” Mr. Trump said in remarks at his Mar-a-Lago estate in Florida. “It is in this vital national security interest of the United States to prevent and deter the spread and use of deadly chemical weapons.”    Shouldn't that "from where" be either "from which" or else just "where" without "from?"


I just browsed a site a while ago that was flagged as an "attack site" or has malware, but Firefox didn't warn before I went into it. Only when I opened a new tab with another page from the site did it block the page.   How do I check for vulnerabilities on my system since I think there are no anti-malware available for Ubuntu? If there are, please do tell.  Thanks!


Super Bowl home field advantage - home team vs away?

My understanding is that the AFC and NFC alternate nominal home and away team status in the Super Bowl. In the theoretical case where a team makes it to the Super Bowl in the same year that their stadium hosts the Super Bowl, does that in any way alter home and away team calculus? Would that "home" team perhaps still be required to use the visitor locker room in their own stadium? Would they still use their away uniforms?


Split a string by spaces -- preserving quoted substrings -- in Python

I have a string which is like this:  this is "a test"   I'm trying to write something in Python to split it up by space while ignoring spaces within quotes. The result I'm looking for is:  ['this','is','a test']   PS. I know you are going to ask "what happens if there are quotes within the quotes, well, in my application, that will never happen.


Why isn't the up/downvote ratio visible to everyone when the information is available anyway?

Low rep users can't see how many downvotes/upvotes a question or answer got, they can only see the total score.  Except they actually can. They can go to the poster's profile, click the reputation tab, and see downvotes and upvotes there.  This is a rather inconvenient and boring way to do it, but the information is available.  So if the information is available anyway, why not:  1. Give low-rep users the ability to see the ratio.  or  2. Prevent low-rep users from seeing the downvotes in the reputation tab of the profile.  If one of these was implemented, the system would be consistent.  Why is this information hidden from low-rep users on the question itself, but available if they go to the poster's profile?