If $f\colon \mathbb{R} \to \mathbb{R}$ is one-to-one and differentiable at $a$ with $f'(a) \ne 0$, must $f^{-1}$ be differentiable at $f(a)$?  I'd like proofs and/or counterexamples, or citation of same, or even just a good hint (I should be able to figure this out!).  I know that the answer is Yes if $f^{-1}$ is at least continuous at $f(a)$ (that's the Inverse Function Theorem in the form cited in ) or if $f$ is differentiable (or even continuous, or even strictly monotone) on a neighbourhood of $a$ (since this proves continuity of $f^{-1}$, for example by the argument in  [answer], reducing to the previous case).  And I know that the answer is No if $f$ is not assumed to be one-to-one (counterexample: $f(x) = x + x^2 \sin(1/x)$ for $x \ne 0$, $f(0) = 0$, $a = 0$) or if $f'(a)$ is allowed to be zero (counterexample: $f(x) = x^3$, $a = 0$).  But in between, there is this case that I do not know.  (Note that this question is different from the one at , which asks about what happens when $f$ is differentiable on a neighbourhood of $a$, in which case the answer is Yes as remarked above.  But I'm only assuming that $f$ is differentiable at $a$ itself, in which case the answer turns out to be No, as seen in the accepted answer below.  The other question did, however, receive an answer to my question in the addendum to its accepted answer.)

I had an exam today, and I was asked about the inverse function theorem, and the exact conditions and statement (as stated in Mathematical Analysis by VA Zorich): Let $X, Y \subset \mathbb{R}$ be open sets and let the functions $f: X \to Y$ and $f^{-1}: Y \to X$ be mutually inverse and continuous at points $x_{0} \in X$ and $y_{0}=f(x_{0})$, respectively. If $f$ is differentiable at $x_{0}$ and $f'(x_{0}) \neq 0$, then $f^{-1}$ is also differentiable at $y_{0}$  and its derivative is $$(f^{-1})'(y_{0})=(f'(x_{0}))^{-1}=\frac{1}{f'(x_{0})}.$$  Then I was asked to come up with an example which would show that the condition that $f^{-1}$ be continuous at $y_{0}$ is not redundant, i.e. that there exists a differentiable bijection $f: \mathbb{R} \to \mathbb{R}$ such that $f'(x) \neq 0$ for all $x \in \mathbb{R}$, but whose inverse $f^{-1}$ is non-differentiable at some point $y_{0} \in \mathbb{R}$ (my professor stated that both the domain and range are $\mathbb{R}$, but I'd be open to any example whose domain/range are open subsets of $\mathbb{R}$). I couldn't come up with an answer on the spot, so I was left with a homework assignment, which I'm shamelessly asking for help with here.  Here are some examples that almost, but don't quite fit the bill:   $f(x)=x^3, f:\mathbb{R} \to \mathbb{R}$, whose inverse $f^{-1}(y)=\sqrt[3]y$ is not differentiable at $0$, but the problem is that $f'(0)=0$. If $f'(x) \neq 0$ were removed as a conditions, many counterexamples could be easily found, because any bijection $f$ whose derivative is zero at $x$ implies that $f^{-1}$ is not differentiable at $f(x)$. An example which is possibly closer to what I'm looking for is the one found in the answer of , which fits the bill completely except for the domain/range, because $f^{-1}$ is not continuous at 1, let alone differentiable, but its domain is not an open or connected set, so it wouldn't be easy to extend its domain to $\mathbb{R}$ and still keep all of its properties.   I'm aware that the inverse $f^{-1}$ of a continuous bijection $f$ defined on an interval ($\mathbb{R}$ in this case) is also continuous, so the "pathological inverse" that I'm looking for is continuous (unlike example 2), but not differentiable (i.e. "spiky") at a point, even though $f$ isn't "spiky" anywhere.


I have tried for some time to find out a way to populate a new page with a few paragraphs to save time on most of the pages (but which might change position or even get dropped for some pages) but so far haven't found a way to do.  I think I have found out how to do the paragraph adding part, but what I am missing is how to fire the code when a new node of relevant content type is created.  I have tried hook THEME_node_create and THEME_node_insert, but they seem not to be fired when a new node is requested. I read that not all hooks are implemented for a theme but how then to achieve this functionality?   I probably (as most of the times) am missing something trivial, but please, help me find the light.  wbr  hank

I have a paragraphs field that takes a term reference.  I need to count how many terms there are for a specific vocabulary and then create that many instance of the paragraphs multiple value field for when creating a node of a certain type. Can this be done with Hook_form_alter ?  It is important that these fields are loaded when the node creation form is loaded rather than the user having to click add more  Any help would be greatly appreciated  I have tried this but when saving the node it doesn't save the new fields  function hook_form_alter(&$form, $form_state, $form_id) {    if ($form_id == 'my_form') {    $item = $form['field_features']['widget']['0'];    // get taxonomy terms   $query = \Drupal::entityQuery('taxonomy_term');   $query->condition('vid', "my_voc");   $tids = $query->execute();   $terms = \Drupal\taxonomy\Entity\Term::loadMultiple($tids);    $count = count($terms);    $i = '1';   foreach($terms as $term){     $form['field_features_para']['widget'][$i] = $item;     $form['field_features_para']['widget'][$i]['#delta'] = $i;     $form['field_features_para']['widget'][$i]['#weight'] = $i;     $i ++;   }  } }


I've tried the top comment here  but when I restart the computer the service is back up and running again.  If I manually go into services.msc and change the Startup type to "Disabled", change the Service Status to "Stop" and then Click "Apply" and then "OK", after rebooting the computer it is still disabled.  This is the commands I am issuing  sc stop "igfxCUIService1.0.0.0" sc config "igfxCUIService1.0.0.0" start= disabled   And the following is the logging  SERVICE_NAME: igfxCUIService1.0.0.0      TYPE               : 10  WIN32_OWN_PROCESS       STATE              : 3  STOP_PENDING                              (STOPPABLE, NOT_PAUSABLE, IGNORES_SHUTDOWN)     WIN32_EXIT_CODE    : 0  (0x0)     SERVICE_EXIT_CODE  : 0  (0x0)     CHECKPOINT         : 0x0     WAIT_HINT          : 0x0 [SC] ChangeServiceConfig SUCCESS

I want to disable a Windows service but I don't want to:   Open the "Services" management console  Scroll to the name of the service Right-click Properties (or double-click) Change the Startup Type: to disabled Apply Click "Stop"   I don't want to  but instead, just disable it.


I have read through many resources but I still don't understand what are the difference between them. Can anyone give good examples that is able for me to imagine the different and explain what is difference between them?  Thank You

There are lots of other questions on Graphic Design which partly cover this, e.g. .  However, I have become frustrated at the number of questions and answers which confuse the two terms. I think understanding the difference is important.  So here's a place to answer this question well and clear up the confusion!


I've Been looking at getting an android for Ubuntu and i want to know which phones are compatible if some one could point me to a list of compatible phones i would be happy.i haven't been able to find a phone list anywhere that can give me a list of phones that fully work with Ubuntu touch/phone. all i need is the list but if some one also knows which phone is fastest with it (I'm looking at CPU speed) id be happy to. so far the ones i have been able to confirm that work are all 1.7Ghz and below but i know there are ones with 2.7 and i want to know if they work, I would assume not since they are all really new and haven't had drivers developed for them.  thanks in advanced for any replies.

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


I know this is a common question, but I still can't seem to find a great regular expression to use when validating email addresses. What is the best regular expression you have or have seen for validating emails with below condition?   email constructor: first_element@second_element first_element: the first element (user name part) second_element: the second element (domain part)    The condition is: All the element not contain spaces, control characters, or non-ASCII characters. thanks

Over the years I have slowly developed a  that validates MOST email addresses correctly, assuming they don't use an IP address as the server part.  I use it in several PHP programs, and it works most of the time.  However, from time to time I get contacted by someone that is having trouble with a site that uses it, and I end up having to make some adjustment (most recently I realized that I wasn't allowing 4-character TLDs).  What is the best regular expression you have or have seen for validating emails?  I've seen several solutions that use functions that use several shorter expressions, but I'd rather have one long complex expression in a simple function instead of several short expression in a more complex function.


I'm sorry for telling that I've a little bit weak on LINQ, I always do write SQL query before I start working on the complicated LINQ.  I want to ask that how to convert this SQL Query into LINQ with LEFT JOIN with multiple ON conditons with the OR operator.,  m.MerchandiseId will be use for twice in ON condition  SELECT     * FROM     Inbox AS i     INNER JOIN [User] AS u ON i.FromUserId = u.UserId     LEFT OUTER JOIN Merchandise AS m ON         u.MerchandiseId = m.MerchandiseId         OR         i.ToMerchantId = m.MerchandiseId WHERE     i.ToCompanyId = 10     OR     i.FromCompanyId = 10    var message = (from i in db.Inbox                join u in db.User on i.FromUserId equals u.UserId                join m in db.Merchandise on u.MerchandiseId equals m.MerchandiseId //here I want to ON i.MerchantId = m.MerchandiseId, but it doesn't allow                 where i.ToCompanyId == user.CompanyId || i.FromCompanyId == user.CompanyId                 orderby i.CreatedAt descending                 group m.MerchandiseId by new { m.MerchandiseId, m.MerchandiseName } into grp                 select new                 {                        MerchandiseId = grp.Key.MerchandiseId,                        MerchandiseName = grp.Key.MerchandiseName,                        InboxMessage = (from e in db.Inbox                                         join us in db.User on e.FromUserId equals us.UserId                                          join mer in db.Merchandise on us.MerchandiseId equals mer.MerchandiseId                                           where mer.MerchandiseId == grp.Key.MerchandiseId                                           orderby e.CreatedAt descending                                           select e.InboxMessage).FirstOrDefault(),                        CreatedAt = (from e in db.Inbox                                     join us in db.User on e.FromUserId equals us.UserId                                     join mer in db.Merchandise on us.MerchandiseId equals mer.MerchandiseId                                      where mer.MerchandiseId == grp.Key.MerchandiseId                                      orderby e.CreatedAt descending                                      select e.CreatedAt).FirstOrDefault(),                                        }).ToList();   The bottom LINQ Query I've write for it. However, I just can work on the left join with multiple ON clause in LINQ. Appreciate if someone would help me on this. Thanks!

I need to do a LINQ2DataSet query that does a join on more than one field (as  var result = from x in entity join y in entity2         on x.field1 = y.field1  and            x.field2 = y.field2   I have yet found a suitable solution (I can add the extra constraints to a where clause, but this is far from a suitable solution, or use  solution, but that assumes an equijoin).  Is it possible in LINQ to join on multiple fields in a single join?  EDIT  var result = from x in entity              join y in entity2              on new { x.field1, x.field2 } equals new { y.field1, y.field2 }   is the solution I referenced as assuming an equijoin above.  Further EDIT  To answer criticism that my original example was an equijoin, I do acknowledge that, My current requirement is for an equijoin and I have already employed the solution I referenced above.  I am, however, trying to understand what possibilities and best practices I have / should employ with LINQ. I am going to need to do a Date range query join with a table ID soon, and was just pre-empting that issue, It looks like I shall have to add the date range in the where clause.  Thanks, as always, for all suggestions and comments given


Let f be holomorphic on the whole complex plane. If f < $\frac{1}{|Im(z)|} $ for all in C \ R, then f is the zero function?  I tried to use that along all straight lines where it is not R, f is bounded and tried to use Liousville (as if f is constant it would be obvious...). But this did not work...  What is the correct approach?

Let $f(z)$ be an entire function such that $$|f(z)|<\frac{1}{|\text{Im}(z)|},\qquad z\in\Bbb C-\Bbb R.$$ The question asked me to prove that $f(z)=0$. At least looking at it, it really seems to have an application of Liouville's theorem lurking around somewhere, but I haven't found it.   My thoughts first led me to think about doing this by contradiction and using Picard's little theorem. So, I've considered a strip containing the real axis (say of width $2$ for simplicity). This will imply the complement maps into the unit disk, which implies that this strip has to map almost everywhere else on the complex plane. Now, on the imaginary axis, I know that $f(z)$ will vanish as $z\to\infty$, and this seems like it might be useful. I'm sort of under the impression $f(z)$ might have an essential singularity at $\infty$, which would mean $f(1/z)$ has an essential singularity at $0$. Either way, it of course can't have a pole at $\infty$ because of $f(z)$ vanishing on the imaginary axis, and if it is a removable singularity, it must be $0$, which still gives the solution. Therefore, I think it must have something to do with $f(z)$ having an essential singularity at $\infty$.   I was hoping to combine this with the above inequality and deduce a contradiction, but I haven't thought of one yet.   Any hints or suggestions? I'm studying for a prelim. exam, so this isn't homework.  Update: So, in the spirit of searching methods using the essential singularity at $z=0$, we have $$\left|f\left(\frac{1}{z}\right)\right|\leq\frac{1}{\left|\text{Im}\left(\frac{1}{z}\right)\right|}=\frac{|z|^2}{|y|}.$$ Thus, for $|y|>1$, we have $$\left|f\left(\frac{1}{z}\right)\right|<|y|\left|f\left(\frac{1}{z}\right)\right|<|z|^2.$$ Thus, if I can show that $|f(1/z)|$ is a polynomial, we'll know it can't have an essential singularity at the origin, concluding my proof.


I'm using Ubuntu 14.04 with Gnome as primary window manager (not Ubuntu Gnome, just installed Gnome after Ubuntu). I often tend to use pm-hibernate to get into hibernation, but when I boot again the resume sometimes, but not always, fails and the computer reboots. At the second boot, the GRUB bootloader screen won't countdown the timer anymore and it will wait for my input. I'd really like to analyze why this is happening, but I don't even know in which log file to look for "resume errors" or where to start. Can you give me a hint on this?  About a year ago it all worked very well, but suddenly (I don't know when exactly) that all started and I don't know what I have changed to make this happen.  Kind regards,  Daniel

I'm running 14.04 on a new XPS 13. In order to support the newer hardware, I'm running a mainline 3.19 kernel.   Hibernate resume has been iffy with the entire 3.19 kernel line, but recently (3.19.5) pm-hibernate no longer works at all. The screen will either a) switch off momentarily, then back on with all inputs frozen or b) switch off entirely, and fail to resume upon power on (despite displaying the correct resume-from-uuid message).  I have enough swap space (and it has worked in the past), I have checked that the uuid is being correctly referenced, and nothing seems particularly amiss in /var/log/pm-suspend.log (last 200 lines here: )  Thanks for your help.


Prove or disproved that for every undirected graph $G$, there is an orientation $D$ on $G$ such that |$deg^+ (v) - deg^- (v)$| $\le 1$ ??

The net-degree of a vertex $v$, denoted $\text{netdeg}(v)$, in a digraph $G$ is defined by  $$ \text{netdeg}(v)=| ~ \text{outdeg}(v) - \text{indeg}(v) ~| $$  where $\text{outdeg}(v)$ and $\text{indeg}(v)$ are the out-degree and in-degree of $v$.  Show that the edges of any multigraph may be oriented so that $\text{netdeg}(v) \leq 1$ for all its vertices $v$.  My first thought was to order the vertices and alternate edges in and out beginning at the first vertex then move on to the next vertex and orient the remaining edges depending on the net-degree of the remaining vertices, but this approach does not seem to work.


The current description for  badge is:  Voted on 600 questions and 25% or more of total votes are on questions   This sounds a bit strange. Voted on X were at least 25% is X. Should the word "Post" be used instead? Or word "answer" to be more clear.   First suggestion:  Voted on 600 posts and 25% or more of total votes are on questions   Edit: Second suggestion:  description (which strange enough is not the same as the badge page):   Vote on 600 questions, and have at least 25% of the total number of votes cast be votes on questions

Formerly List of all badges with full descriptions.  What are badge name's requirements? Why didn't I get badge name ? Which badges can I earn multiple times?    Jump to:                    Note: Some badges are awarded based on score. The term score means the total number of upvotes minus the total number of downvotes.  Any badge with a *** next to it is one of 20 badges that count towards the  displayed on a moderator candidate in an election. The candidate score is a total of 40 points: the first 20 are awarded based on the user's rep divided by 1000 and rounded down; the second 20 represents the total number of unique badges earned of the 20 that count. Note that if the same badge is earned multiple times, it will only count once towards the candidate score.  Any badge with a "(retired)" next to it is no longer awarded, but is retained by users who previously earned them. See  for more info on what it means for a badge to be retired.       Visit the  of the  on any site to see a complete list of badges that you can filter by earned, unearned, or type.


I am working on Git.I was merging one binary file it gave me conflicts.   Can someone please tell me why binary files conflicts. What are the causes.Is it because of the uncommitted changes on current branch or its just because of the different versions of the binary files?

I've been using Git on Windows (msysgit) to track changes for some design work I've been doing.  Today I've been working on a different PC (with remote repo brian) and I'm now trying to merge the edits done today back into my regular local version on my laptop.  On my laptop, I've used git pull brian master to pull the changes into my local version. Everything was fine apart from the main InDesign document - this shows as a conflict.  The version on the PC (brian) is the latest one that I want to keep but I don't know what commands tells the repo to use this one.   I tried directly copying the file across onto my laptop but this seems to break the whole merge process.  Can anyone point me in the right direction?


Suppose I do this:  $(target).blur(function(e){   //do stuff });   Is there a way to fetch the object that was clicked on in order to trigger the blur action?  I tried using e.target, but that appears to be returning the object attached to the blur action rather than the clicked object.

Suppose I attach an blur function to an HTML input box like this:  <input id="myInput" onblur="function() { ... }"></input>   Is there a way to get the ID of the element which caused the blur event to fire (the element which was clicked) inside the function? How?  For example, suppose I have a span like this:  Hello World   If I click the span right after the input element has focus, the input element will lose its focus. How does the function know that it was mySpan that was clicked?  PS: If the onclick event of the span would occur before the onblur event of the input element my problem would be solved, because I could set some status value indicating a specific element had been clicked.  PPS: The background of this problem is that I want to trigger an AJAX autocompleter control externally (from a clickable element) to show its suggestions, without the suggestions disappearing immediately because of the blur event on the input element. So I want to check in the blur function if one specific element has been clicked, and if so, ignore the blur event.


I am deploying Airwatch to my organization. On company-owned laptops, I would like to lock them down if/when the device is ever un-enrolled. There is no built-in method of doing this, so I am looking for a script to do it. My relevant background: I know very little batch, some powershell, a lot of vbscript (for classic ASP).   I would like one or both of the following:   Reset all user passwords on the laptop to something preset Create a specific local admin and then disable all other local users   I know I can use "net user" to get a list of users, but I do not know how to use that list to actually disable the users or change their passwords. The batch commands to fit this logic would be ideal:  net user NewAdmin Password /add  net localgroup administrators NewAdmin /add  UserList = net user output  For each UserName in UserList       If UserName <> "NewAdmin" Then           net user UserName NewPassword           net user UserName /active:no      End If Next

I'm looking to get the result of a command as a variable in a Windows batch script (see  for the bash scripting equivalent).  A solution that will work in a .bat file is preferred, but other common windows scripting solutions are also welcome.


Hey everyone so I have a few questions and I would really appreciate a response from those that are "100 factually certain of their answers" over someone who is merely speculating.  So I know that when I create my hangout, a URL is created for me to plug anywhere on line.  Is that URl for those to watch my hangout or to join it?  Also, who can join my Google+ hangout? Anyone? Only those with Gmail? Those with Google+?

If I start a Google+ Hangout, is there anyway to send my friends a link directly to that Hangout post? I couldn't find any options.   So I have to send people a link to my profile, and let them click on the join hangout button. I prefer not to do that since the hangout post may be buried by my other updates.


What I am trying to do I have a simple function for string input validation. Code: def get_string_input(prompt):     while True:         try:             value = str(input(prompt))         except ValueError:             time.sleep(0.3)             print("Incorrect command. Please try again")             continue          if type(value) != str:             time.sleep(0.3)             print("Incorrect command. Please try again")             continue         else:             break     return value  # Test  get_string_input('What is your name? ')   Problem: When I run the program, I recieve the following error:  I can see that my indentation is correct, so why is it giving me an error?

When I compile the Python code below, I get      IndentationError: unindent does not match any outer indentation level     import sys  def Factorial(n): # Return factorial     result = 1     for i in range (1,n):         result = result * i     print "factorial is ",result     return result   Why?


I am trying to make static library for solving probability and stats.  I am getting LNK2019 unresolved external symbol error when running my code. I think the program isnt detecting the definitions of function from the .cpp file and i dont get the issue here. Also i have given the main file directions for the library so no issue there. I am new in using headers and templates so kindly help. The error occurs when the program calls the constructor for the object:  > LNK2019   unresolved external symbol "public: __thiscall ProbnStatslib::means<float>::means<float>(void)"(??0?$means@M@ProbnStatslib@@QAE@XZ) referenced in function_main   Header file:  // .h file #ifndef PROBNSTATSLIB_H #define PROBNSTATSLIB_H #include<iostream> #include<vector>  namespace ProbnStatslib {     template<typename any>     class means      {     private:         std::vector<any> xi_mean;         int N;     public:         means();         void initializer(int size);         void CalcMean();      };  } #endif   The .cpp   // .cpp #include<iostream> #include"ProbnStatslib.h" #include<vector> using namespace std; namespace ProbnStatslib {     template<typename any>     means<any>::means()     {         cout << "object constructed" << endl;         cout << "Enter number of ouccrances:" << endl;         cin >> this->N;         initializer(this->N);     }     template<typename any>     void means<any>::initializer(int size)     {         cout << "Enter event values or Xi of size:"<< size << endl;          /*for (any value : xi_mean)         {             cin >> this->xi_mean;         }*/     }     template<typename any>     void means<any>::CalcMean() {         cout << "Calculating" << endl;     }  }   The main file:  #include <iostream> #include <vector> #include "ProbnStatslib.h" using namespace std; using namespace ProbnStatslib; int main() {     means<float> myobj;     return 0; }

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


Since changing my Mac password I constantly see the message "" in my iCloud settings.    What is this for:   What does providing this password do?  What does not providing this password not to (e.g., are there features I'll miss out on)? Can I safely ignore it?  Is it something I should worry about (and if so, how do I get rid of it)?

I recently changed my Mac password, and a System Preferences notification comes up, asking me to "confirm Mac password to continue using iCloud":    However, when I click Continue, all that happens is a dropdown appears asking me to continue, then when I continue, nothing happens. I have no idea why this is happening, does anyone have any feedback?


I am creating a IEEE paper, but all my references are displayed as [?]. Why is that? What can I do to get the references properly typeset?  Here is my code:  \documentclass[twocolumn,twoside]{IEEEtran} \usepackage{cite} \begin{document} \title{DDD} \author{AAA} \maketitle \begin{abstract}  hhh \end{abstract} \section{Introduction}  hghg \cite{vvv} \bibliographystyle{IEEEtran} \bibliography{myreference} \end{document}   and here is my .bib file:  @article{vvv,   author  = {xxx},   title   = {cryptography},   journal = {dddd},   year    = {2012},   volume  = {CS},   number  = {04},   pages   = {161} },

I've browsed the forums and found a number of posts that have addressed this issue, but none of the solutions seem to work for me. I have the following script that I just copied from the bibtex home page to get familiar with it. Instead of the citation number I get a question mark. I compile using Latex+Bibtex+Latex+Latex+PDFLatex+ViewPDF just as has been previously suggested and the problem persists.   \documentclass[11pt]{article} \usepackage{cite}  \begin{document}  \title{My Article} \author{Nobody Jr.} \date{Today} \maketitle  Blablabla said Nobody ~\cite{Nobody06}.  \bibliography{mybib} \bibliographystyle{plain} \end{document}   My bibliography (Bib.bbl)  @misc{ Nobody06, author = "Nobody Jr", title = "My Article", year = "2006" }    Looking at previous posts one thing that is concerning is that my .bbl looks empty as shown below. Further, I don't have a .blg  \begin{thebibliography}{}  \end{thebibliography}


Find $E[N]$ for $N = \min\{n:U_1+U_2\cdots+U_n>1\}$ where $U_1,U_2, . . .$ are independent uniform (0,1) random variables.   I may be way off base with my thinking here, but is $\min\{n:U_1+U_2\cdots+U_n>1\}$ the same as $\max\{n:U_1+U_2+\cdots+U_n\leq1\}$? If so, I'm thinking of this as a renewal process where n is the maximum number of "arrivals" by time = 1. Then I'm just finding E[N(t)] which is the renewal function m(t) that satisfies the integral equation $m(t)=F(t)+\int_0^tm(t-x)f(x)\cdot dx$ and I know where to go from there.

Let $X_1,X_2,X_3,\ldots $ be an i.i.d. sequence of uniform random variables over $[0,1]$. Define $$N= \min \{n \geq 1:X_1+\cdots+X_n>1\}$$ Find $P\{N>n\}$ and compute $E[N]$.


/private/var/folders is not getting empty after reboot. The folder is 200 GB! I tried safe mode too and it didn't change.  How can I thin out the folder(s)?

I have this folder /private/var/folders/bf/ with 3GB of what seems temporary files. Can I delete this folder?


I would like to limit my http request for only one virtualhost on apache, is it possible to do this via iptables for only one virtualhost ? I prefer to do not use apache if it's possible for better performance. If not how I can limit requests for only one virtualhost on apache 2.2 ?

Someone has pointed their domain (www.bomberball.net) to the same IP as my domain (www.kapparate.com) , and Google is now showing the former when searching for Kapparate, rather than the latter. What's the best way to block requests coming from www.bomberball.net ?


This is a follow-up to this post -  I have my node-based texture (thanks to moonboots) and now I need to somehow get it into UE4. I read up on texture baking but I don't know if it makes more sense to try that or would it be easier to recreate the texture directly in UE4? I pressed the Bake button in Blender and it saved internally, how do I export that out into an image file? Thanks

I have a sphere having a planet material MADE WITH NODES, and I want to convert this material into an image texture; because this material is made with nodes and only works in Blender, but I want to use in another software. This is my sphere material :   For Example : This is Jupiter :  And this is the texture :  In this case I used a downloaded image for Jupiter to be the material but I want the opposite, I want to change the material to image texture Like The shape of Jupiter texture. Is there anyway in Blender that can achieve my goal ? This is the file with my sphere material .  Textures Needed :  Albedo / Color / Diffuse Normal Map Roughness Glossines  I am using normal nodes and I am not useing the new Principled-shader


Im running centos 6.8 with virtualmin  My server is from kimsufi.com with a disk space of 2tb  the file system is 20gb   below I have df -h output:  [root@server ~]# df -h  Filesystem      Size  Used Avail Use% Mounted on rootfs           20G  8,7G  9,7G  48% / devtmpfs        7,8G  176K  7,8G   1% /dev tmpfs           7,9G     0  7,9G   0% /dev/shm /dev/sda2        20G  8,7G  9,7G  48% / /dev/sda2        20G  8,7G  9,7G  48% /var/named/chroot/etc/named /dev/sda2        20G  8,7G  9,7G  48% /var/named/chroot/var/named /dev/sda2        20G  8,7G  9,7G  48% /var/named/chroot/etc/named.conf /dev/sda2        20G  8,7G  9,7G  48% /var/named/chroot/etc/named.rfc1912.zones /dev/sda2        20G  8,7G  9,7G  48% /var/named/chroot/etc/rndc.key /dev/sda2        20G  8,7G  9,7G  48% /var/named/chroot/usr/lib64/bind /dev/sda2        20G  8,7G  9,7G  48% /var/named/chroot/etc/named.iscdlv.key /dev/sda2        20G  8,7G  9,7G  48% /var/named/chroot/etc/named.root.key [root@server ~]#    with df -i 48% is 100% Im a newbea but my server was working fine since one month ago.  I tried to clear the cache after searching google with the following command:  sudo rm -rf /var/cache/yum/x86_64/6/$REPONAME   so after running that command I logged in webmin and instead of the error in the title I got webmin screen it worked and local disk space was 50% in the panel.  after than I tried to restart mysql via /etc/init.d/mysqld restart and mysql failed to start   Now I dont have also the mysql   the last error is /usr/bin/mysqlshow: Can't connect to local MySQL server through socket '/var/lib/mysql/mysql.sock' (2)  and last again Failed to open /etc/webmin/apache/site for writing : No space left on device messagge in webmin or virtualmin.  Guys Im very confused and afraid to lost my databases please if anyone can help me here to solve this problem will be very appreciated  edit:  [root@server ~]# ls -l /var/spool/postfix/ total 56 drwx------  2 postfix root     4096 Oct 25 04:46 active drwx------  2 postfix root     4096 Oct 24 21:45 bounce drwx------  2 postfix root     4096 Nov 10  2015 corrupt drwx------  6 postfix root     4096 Oct 10 02:17 defer drwx------  6 postfix root     4096 Oct 10 02:17 deferred drwx------  2 postfix root     4096 Nov 10  2015 flush drwx------  2 postfix root     4096 Nov 10  2015 hold drwx------  2 postfix root     4096 Oct 25 04:46 incoming drwx-wx---  2 postfix postdrop 4096 Oct 25 04:46 maildrop drwxr-xr-x. 2 root    root     4096 Oct 25 08:58 pid drwx------. 2 postfix root     4096 Oct 25 11:21 private drwx--x---. 2 postfix postdrop 4096 Oct 25 11:21 public drwx------  2 postfix root     4096 Nov 10  2015 saved drwx------  2 postfix root     4096 Nov 10  2015 trace [root@server ~]#

I have a filesystem that has lots of small files. Currently about 80% of inodes are used (I checked with df -i), however only 60% of disk space is used. How can I 'increase' the number of inodes? If it was just disk space, I know that I could just increase the size of the disk (this disk is on LVM). If I increase the size of the disk, will that make me have more inodes?  I'm willing to grow the filesystem this disk is on, if that'd help.


Which one of the folowing is efficient way to store list of objects?   Hashset<object> listOfObjects = new HashSet<object>();   or  List<object>listOfObjects = new List<object>();

It's clear that a search performance of the generic HashSet<T> class is higher than of the generic List<T> class. Just compare the hash-based key with the linear approach in the List<T> class.  However calculating a hash key may itself take some CPU cycles, so for a small amount of items the linear search can be a real alternative to the HashSet<T>.  My question: where is the break-even?  To simplify the scenario (and to be fair) let's assume that the List<T> class uses the element's Equals() method to identify an item.


I need to prove for  $k>1$ that is: $n\log(n) \in \mathcal{O}(n^k)$ A also need to mention what happens in case that $k = 1$. So actually, to prove $n\log(n) \in \mathcal{O}(n)$ which I did so: For big-Oh Notation $n\log(n) \in \mathcal{O}(n)$ exists an constant $c$ and $n_0$ such that for $n\gt n_0$ : $n\log(n) \le  c * \mathcal{n}$  //  $\div\mathcal{n}$ gives: $log(n) \le c$  // this is NOT TRUE weil there is no such a constant $c$ that for all $n\gt n_0$ But I have no idea how to prove $(n^k)$. Please help :)

How can I prove that $\log^k(n) = O(n^\epsilon)$? (for any $\epsilon > 0 $ and for any integer and positive $k$).  I tried to do it by - definition , and to prove that exists $c,n_0 > 0$ so that for any $n > n_0 $ exists: $c \cdot n^\epsilon > \log^k(n) $, but I don't have idea how to continue for this point.    I will be happy to listen ideas :).


I saw religious SE sites like Hinduism, Christianity, Islam, etc. But over all we can say God regardless of religious. I want to ask a question about God, but not specific to a religion. Is there a separate SE available?  Note: My question will be 'If God exist then why do people, who didn't do any crime or sin (particularly children or new born baby), get deadly diseases?  The pain they are getting is their own pain that God is not feeling instead of them.'  If I want to ask this question, what is the best suitable site to ask and I don't mind if it will be closed as off topic.  Note: I can ask this question on Hinduism as I'm based in that religion, but I want a generic answer.

Stuff like polls, recommendations based on subjective constraints, puzzles, webcomics etc. do not belong on the serious main SE sites, where professionals should be considered at work and having just a few spare minutes ("code's compiling") to answer questions, so they should not be distracted by such things. However, I'd also like to have a home for these things still using the SE engine. For the reason I mentioned before, this needs to be a separate place though. Let's call it four.[sitename-here].com.


I am beginning to learn photography and am buying my first hardware. I have boiled down to Nikon D3300 with Nikkor 55-200mm lens. I am also looking for a tripod because I guess one needs a stable hand to take good shots using a lens. So the question is: Are all tripods suitable for all cameras or there is a specific tripod for each brand?   In any case what tripod should I use? I live at the edge of a forest (I am not allowed to go inside without permission). But wild peacocks and deer do venture out. I wish to capture them (in my camera) but cannot carry the camera the whole day in my hands.  Can I use the same tripod with binoculars?  This question is partly answered in another place but I asking as to how to decide which tripod is more suitable for my requirement of capturing scenery and wild animals. Are there different tripods good for different requirements?

I am a novice in photography and my current camera (Sony alpha 230 kit) which I recently have bought is the first DSLR of mine. Soon I'd like to buy a tripod for it.  Please advise me what should I take into consideration when choosing a tripod? At present all the tripods seem similar to me and I feel that I need some help in choosing the right one.  From what I tend to shoot now, I think that the primary usage of the tripod will be landscape and portrait (outdoor) photography.


I do not understand in terms of coefficients of friction why this happens? From my understanding the ground and the tire still have the same coefficients of friction right? So why is there less traction when it is stopped then when it is moving?

When dragging an object, there is a greater start-up force than the force it takes to keep it moving. Why is this? Why are there two different values for friction?


Code-igniter: I am using simple mail() function in cron job, but in mail its showing via crystal url name server in from section??  In mail its showing like:     from:   Domain Name <noreply@domainname.com> via crystal.urlnameserver.com   My code snippet:  $headers = "MIME-Version: 1.0" . "\r\n"; $headers .= "Content-type:text/html;charset=UTF-8" . "\r\n"; $headers .= 'From: Domain Name <noreply@domainname.com>' . "\r\n"; .... mail($mailId, $subject, $mentor_message, $headers);   Why its showing "via....." text?? please suggest me the changes??  I didn't mention it anywhere, then why its coming like that?  My cron job is in pure core-php.

I am using PHP with Apache on Linux, with Sendmail. I use the PHP  function. The email is sent, but the envelope has the Apache_user@localhostname in MAIL FROM (example nobody@conniptin.internal) and some remote mail servers reject this because the domain doesn't exist (obviously). Using mail, can I force it to change the envelope MAIL FROM?  EDIT: If I add a header in the fourth field of the mail() function, that changes the From field in the headers of the body of the message, and DOES NOT change the envelope MAIL FROM.  I can force it by spawning sendmail with sendmail -t -odb -oi -frealname@realhost and piping the email contents to it. Is this a better approach?  Is there a better, simpler, more PHP appropriate way of doing this?  EDIT: The bottom line is I should have RTM. Thanks for the answers folks, the fifth parameter works and all is well.


Not all the time, of course, but it seems odd in retrospect as the chief medical officer should be considered too indispensable to risk on a surface mission-McCoy literally risks his life in several TOS episodes, for example.

Ever since the days of Kirk, Spock, and McCoy, bridge officers in Starfleet have always had a prominent role in away team missions.  However, it would seem more logical to me that such hazardous (and, generally, specialized) duties should fall to lower-ranking and/or more dedicated teams.  Of course, it wouldn't have made for great TV if every away team was comprised of a bunch of red-shirts.  And it would definitely increase the show's budget to have an extra group of main characters whose sole purpose was to handle the away missions.  Still, I'm curious to know if there's ever been a real in-universe explanation for this practice?  I know it's been brought up a few times, in a few series/movies, that the Captain should not be taking part in hazardous away team missions.  But nothing is ever said (that I'm aware of) of the rest of the still valuable bridge crew or other senior officers.


I'm trying to create some Apex tests. Of course I am NOT using SeeAllData=true. When I try to insert some instances of Product2, even though I've inserted none before, I get:  System.DmlException: Insert failed. First exception on row 0; first error: DUPLICATE_VALUE, A Product with this SKU already exists.: [StockKeepingUnit] Class.ProductBundleControllerIntTest: line 48, column 1  If I try the following just before the attempted insert:         System.debug('######### EXISTING PRODUCT: ' + [           SELECT Id, StockKeepingUnit            FROM Product2            WHERE StockKeepingUnit != NULL ]);   I get:  17:58:23.557 (3561926690)|USER_DEBUG|[47]|DEBUG|######### EXISTING PRODUCT: ()  Even if I do the following to absolutely guarantee that no previous records could possibly exist and that I am inserting no duplicates, I get the same error:         delete [                 SELECT Id, StockKeepingUnit                 FROM Product2         ];         Map<String, Product2> product2BySkuMap = new Map<String, Product2>();         for (Product2 product2 : TEST_PRODUCT_LIST) {             product2BySkuMap.put(product2.StockKeepingUnit, product2);         }         insert product2BySkuMap.values();   System.DmlException: Insert failed. First exception on row 0; first error: DUPLICATE_VALUE, A Product with this SKU already exists.: [StockKeepingUnit]  Further Notes:  This is an absolutely fresh sandbox, so there really is no data for it to match or to avoid matching.  Also at play within the functionality being tested are Custom Metadata which also needs to have values matching these SKU values.  So even if we could change the SKU for the test, we can't (and shouldn't) change it for the Custom Metadata.   What could I be missing? How can I fix this?

I'm using the Product object and store the product sku within the StockKeepingUnit field. According to the , this field is considered unique, which is totally fine and expected for me. However, when I use apex testing classes, my product2 testing records that I create for testing are conflicting with the product2 records already part of my Salesforce instance. This doesn't make a lot of sense to me because I am not using seeAllData=true in my testing classes, those records in my Salesforce instance should not get into conflict with my testing records. Here is the error message I get when I try to insert a test record that has a product sku equal to a product2 record already part of my Salesforce instance. System.DmlException: Insert failed. First exception on row 0; first error: DUPLICATE_VALUE, A Product with this SKU already exists.: [StockKeepingUnit] I've tested it in a brand new scratch org to the same result. HOW TO REPRODUCE: I've added a new product2 record through the dev console Product2 testExistingProduct = new Product2(StockKeepingUnit='60235280574',Name='Fake Name',IsActive=true); insert testExistingProduct;  Here is the testing class @isTest private class TestDuplicateSku {     @testSetup static void setup() {         Product2 testExistingProduct = new Product2(StockKeepingUnit='60235280574',Name='Fake Name',IsActive=true);         insert testExistingProduct;     }          @isTest static void   TestBasicProductAddProperties() {         Test.startTest();         Test.stopTest();         Product2 updatedProduct = [select id,StockKeepingUnit from Product2 where StockKeepingUnit='60235280574'];         System.assertEquals('60235280574',updatedProduct.StockKeepingUnit,         'Product sku should be defined');     } }  Error message:  TestDuplicateSku.TestBasicProductAddProperties  System.DmlException: Insert failed. First exception on row 0; first error: DUPLICATE_VALUE, A Product with this SKU already exists.: [StockKeepingUnit] force-app/main/default/classes/TestDuplicateSku.cls:5:1


One of my customers wants his webshop to be closed at Sundays. We've made a page that will be shown on Sunday, but what is the best practice concerning SEO?   Return HTTP-status 503 (with a 'Retry-After' header, to tell bot/crawler to come back at Monday 0:00) and display Sunday page Redirect with Javascript (window.location.href) and disallow Sunday page in robots.txt Any other suggestions?   (Of course Javascript is less 'reliable' than a server side redirect, but this is just about SEO)

Someone here might have experience with this problem (it's not my personal problem and never has been):  Say you have a customer who is an observant Jew and he wants his site to be offline somehow (or at least online but unavailable for surfing) during Saturday - Shabat in Hebrew, Sabbath in English.  Is there a way to achieve this goal without causing SEO problem of any kind to the site?    The way I can think of is a full-screen Lightbox that will cover all the site with a small message, but might not actually hurt the SEO as the site itself will be online but without surfing.


In the header file I want to declare an array of NSInterger, what's the best way to do that? I try this code, but it lead to an error  @interface test:NSObject { } @property(nonatomic,readwrite)NSInteger f[4]={1,2,3,4}; // Error!!! @end

I'm having troubles creating a property of an array of integers in Objective-C. I'm not sure whether this is even possible to do in Obj-C so I'm hoping someone can help me in finding out either how to do it correctly or provide an alternative solution.  myclass.h  @interface myClass : NSObject {  @private int doubleDigits[10]; }  @property int doubleDigits; @end   myclass.m  @implementation myClass      @synthesize doubleDigits;     -(id) init {          self = [super init];          int doubleDigits[10] = {1,2,3,4,5,6,7,8,9,10};          return self;     }      @end   When I build and run, I get the following error:     error: type of property 'doubleDigits'   does not match type of ivar   'doubleDigits'


Recently I've brought a caddy for my Lenovo Ideapad 510 to fit in the HDD. Currently using Samsung SSD 850 EVO 240 GB for windows.  Just few days back, I'm starting to see weird icon near the drives in explorer. And I've seen this problem after installing caddy. Even searched about it, but looks like no one is having similar problem as like me.  If somewhere have any idea, please do tell. Thanks

Today, in all my drives in Windows 7 appeared a red icon. I try to delete the IconCache.db but doesn't work.


Ubuntu 18.04.1, GNOME 3.28.2, Tweaks -> Extension: Dash to panel  After some updates 05 Jan 2019 - 08 Jan 2019 I began to see sometimes:  Unstable:   (But this is NOT permanent! For example i made screenshot from normal behavior. + Same troubles on login screen which reduces the extensions effect!)  Stable:    Simple temporary fix - is select language with mouse cursor or twice with keyboard hotkeys.

I see an empty drop down box where the language code of the  should be.  To reproduce the bug: Lock screen or log out and log in again.    I also get the same behavior on the lock screen at the time when I try to log in with my password:    After I tried the workaround (below) the language code on the login screen disappeared as soon as I typed the first character of my password.  Workaround (not permanent): Switching with keyboard (Super+space) or mouse.  System info: Ubuntu 18.04.1 LTS, GNOME 3.28.2.    Please  if also affects you.


Basically the title. I'm building a game with several NPCs and complex systems, and I want it to be nice and modular for modders right from the beginning. So far, I have looked into:  , I don't completely understand these, probably will have to write some custom loading code? I don't know how/if this will let the modders write code.  Lua-Based Modding, I don't particularly like Lua, but I will fall back to it if I absolutely have to (The Unity-Lua  makes this a seemingly very fast way.)  Exposed C# (original idea from this ). But again, as stated in the question raw c# has a lot of disadvantages, not to mention the security risks and compatibility issues.  Minecraft-Style? Completely custom? Basically a lot of events and registries? I'm not sure about this option. To give you an example, there are several Tribes in the game. Ideally, if a modder wanted to make a new tribe they would need to extend from some Tribe base class and then register/add their custom tribe to my AvailableTribes list. Not to mention the models, animations, and sounds for the Tribe NPCs and such.   Any help is appreciated!

I am building a game in Unity using C# and visual studio. I want to make it possible for users to write code in some scripting (for modding purposes) without necessarily opening the source. What are my best options?  I'd prefer well-supported and battle-tested options that integrate well with Unity and visual studio, but I am willing to do a fair amount of work myself as long as it makes scripting as seamless as possible for future modders.


Does anyone have any idea about how to edit like this in Photoshop? I have used Google to search for this, but have found nothing.

I really want to do this kind of effect where it looks like a person is disintegrating away, but I have no idea what it is called:


How do I prove that $\mathbb{Q}(\sqrt{2})$ is or isn't a Euclidean domain?  So if $F$ is a field, then $F[X]$ is a Euclidean domain. I don't see why this means that $\mathbb{Q}(\sqrt{2})$ is a Euclidean domain, because we have $\sqrt{2}$ instead of $X$.

I'm having trouble proving this. This is what I have so far:  Let $F$ be a field. Let $v(x) \rightarrow 1$ for all $x$ not equal to $0$.  So if we let $x$ be in $F$ where $x$ not zero then we can write $x$ as: $x=qy+r$ for some $y$ in $F$. If $r$ not zero then $V(r)=1$.  Not sure what to do from here. I know eventually I'm supposed to get no remainder $(r=0)$ but I'm stuck at applying the definition and valuation map.


Show that every automorphism of $\mathbb{P}^{1}_{\mathbb{C}}$ is given by a linear automorphism of $\mathbb{C}^{2}$.  Equivalently: Show that $\operatorname{Aut}(\mathbb{P}^{1}_{\mathbb{C}})=\operatorname{PGL}_{2}(\mathbb{C})$.  I have no idea where even to start, and I am feeling a little bit ashamed about that. I know this is not true for $\mathbb{P}^{n}_{\mathbb{C}}$ if $n\geq 2$. Can somebody please give me a hint?

Let $k$ be a field, n a positive integer.  Vakil's notes, 17.4.B: Show that all the automorphisms of the projective scheme $P_k^n$ correspond to $(n+1)\times(n+1)$ invertible matrices over k, modulo scalars.   His hint is to show that $f^\star \mathcal{O}(1) \cong \mathcal{O}(1).$ (f is the automorphism. I don't if $\mathcal{O}(1)$ is the conventional notation; if it's unclear, it's an invertible sheaf over $P_k^n$) I can show what he wants assuming this, but can someone help me find a clean way to show this?


How to set same identation for tabular's on different, but successive, pages?   I've two tabular's, each on different, but successive, pages of the document.  To have same identation, I've tried the \noindent, but this doesn't seem to help.  As can be seen on the image, the identation are slightly different.  What mechanism can I use to get same indentation?    \noindent\begin{tabular*}{\columnwidth}[h]{rlrrl} \toprule \multicolumn{5}{l}{\textbf{30s: Environmental Information}} \vspace{5pt} \\ \textbf{Value} & \textbf{Mnemonic} & $\delta$ & $\alpha$ & \textbf{Description} \vspace{5pt} \\ 0x30 & {ADDRESS} & 0 & 1 & Get address of currently executing account. \\ 0x31 & {BALANCE} & 1 & 1 & Get balance of the given account. \\ 0x32 & {ORIGIN} & 0 & 1 & Get execution origination address. \\ 0x33 & {CALLER} & 0 & 1 & Get caller address. \\ 0x34 & {CALLVALUE} & 0 & 1 & Get deposited value by the instruction/transaction. \\ 0x35 & {CALLDATALOAD} & 1 & 1 & Get input data of current environment. \\ 0x36 & {CALLDATASIZE} & 0 & 1 & Get size of input data in current environment. \\ 0x37 & {CALLDATACOPY} & 3 & 0 & Copy input data in current environment to memory. \\ 0x38 & {CODESIZE} & 0 & 1 & Get size of code running in current environment. \\ 0x39 & {CODECOPY} & 3 & 0 & Copy code running in current environment to memory. \\ 0x3a & {GASPRICE} & 0 & 1 & Get price of gas in current environment. \\ 0x3b & {EXTCODESIZE} & 1 & 1 & Get size of an account's code. \\ 0x3c & {EXTCODECOPY} & 4 & 0 & Copy an account's code to memory. \\ \end{tabular*}  \noindent\begin{tabular*}{\columnwidth}[h]{rlrrl} \toprule \multicolumn{5}{l}{\textbf{40s: Block Information}} \vspace{5pt} \\ \textbf{Value} & \textbf{Mnemonic} & $\delta$ & $\alpha$ & \textbf{Description} \vspace{5pt} \\ 0x40 & {BLOCKHASH} & 1 & 1 & Get the hash of one of the 256 most recent complete blocks. \\ 0x41 & {COINBASE} & 0 & 1 & Get the block's beneficiary address. \\ 0x42 & {TIMESTAMP} & 0 & 1 & Get the block's timestamp. \\ 0x43 & {NUMBER} & 0 & 1 & Get the block's number. \\ 0x44 & {DIFFICULTY} & 0 & 1 & Get the block's difficulty. \\ 0x45 & {GASLIMIT} & 0 & 1 & Get the block's gas limit. \\ \end{tabular*}

I'm very new to latex, and I've noticed that using a book class causes the text on one page to be on the right and then left on the next and so on. I'd like for it to all to be on the left or centered. How can I change this?


Could you please explain this issue: can a microprocessor perform on average more than one instruction per clock cycle?

Wikipedia's  says that an i7 3630QM deliver ~110,000 MIPS at a frequency of 3.2 GHz; it would be (110/3.2 instructions) / 4 core = ~8.6 instructions per cycle per core?! How can a single core deliver more than one instruction per cycle?  To my understanding a pipeline should only be able to deliver one result per clock.  These are my thoughts:   Internal frequency is actually higher than 3.2 GHz Some parts of the CPU are asynchronous in a way a humble human like myself cannot understand There are multiple concurrent pipelines per core A pipeline can deliver more than result per clock, an instruction can skip pipeline stages and there are multiple prefetcher to keep up I am missing something


I have a question. That is: in windows the basic apps installer extensions are .EXE and .MSI so what is installer extensions in ubuntu?

I don't know what the exact executable file extension is. Is it .deb or .tar.gz?


Making the following call:  SwingUtilities.updateComponentTreeUI(comp);   which sporadically results in the following error :  Exception in thread "AWT-EventQueue-0"  java.lang.NullPointerException     at javax.swing.plaf.synth.SynthArrowButton$SynthArrowButtonUI.getPreferredSize(SynthArrowButton.java:106)     at javax.swing.JComponent.getPreferredSize(JComponent.java:1662)     at javax.swing.plaf.basic.BasicScrollBarUI.layoutVScrollbar(BasicScrollBarUI.java:666)     at javax.swing.plaf.basic.BasicScrollBarUI.layoutContainer(BasicScrollBarUI.java:866)     at java.awt.Container.layout(Container.java:1511)     at java.awt.Container.doLayout(Container.java:1500)     at java.awt.Container.validateTree(Container.java:1696)     at java.awt.Container.validateTree(Container.java:1705)     at java.awt.Container.validateTree(Container.java:1705)     at java.awt.Container.validateTree(Container.java:1705)     at java.awt.Container.validate(Container.java:1631)     at javax.swing.RepaintManager$3.run(RepaintManager.java:711)     at javax.swing.RepaintManager$3.run(RepaintManager.java:709)     at java.security.AccessController.doPrivileged(Native Method)     at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:80)     at javax.swing.RepaintManager.validateInvalidComponents(RepaintManager.java:708)     at javax.swing.RepaintManager$ProcessingRunnable.run(RepaintManager.java:1731)     at java.awt.event.InvocationEvent.dispatch(InvocationEvent.java:311)     at java.awt.EventQueue.dispatchEventImpl(EventQueue.java:756)     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:80)     at java.awt.EventQueue.dispatchEvent(EventQueue.java:726)     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)   Apparently some component is becoming null. Added the following IF condition but it doesn't help :  if (comp != null)       SwingUtilities.updateComponentTreeUI(comp);   Going through the stack and it is purely a java stack and no reference to custom code. There are actually other NULL exception similar but referencing other Java objects.   Is there a way to iterate through the components in this tree to find which component is returning a null?

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


The /var partition on my intel SSD is getting full. Even though I have increased it size to 100GB, which is quite ridiculous.  The kern.log and syslog. files are each 31.7 GB big.   how can I remove the files? Because just deleting them is denied. What is the cause and how can I prevent this from happening?

( deals with a similar issue, but it talks about a rotated log file.)  Today I got a system message regarding very low /var space.   As usual I executed the commands in the line of sudo apt-get clean which improved the scenario only slightly. Then I deleted the rotated log files which again provided very little improvement.  Upon examination I find that some log files in the /var/log has grown up to be very huge ones. To be specific, ls -lSh /var/log gives,   total 28G -rw-r----- 1 syslog            adm      14G Aug 23 21:56 kern.log -rw-r----- 1 syslog            adm      14G Aug 23 21:56 syslog -rw-rw-r-- 1 root              utmp    390K Aug 23 21:47 wtmp -rw-r--r-- 1 root              root    287K Aug 23 21:42 dpkg.log -rw-rw-r-- 1 root              utmp    287K Aug 23 20:43 lastlog    As we can see, the first two are the offending ones. I am mildly surprised why such large files have not been rotated.  So, what should I do? Simply delete these files and then reboot? Or go for some more prudent steps?  I am using Ubuntu 14.04.  UPDATE 1  To begin with, the system is only several months old. I had to install the system from scratch couple of months back after a hard disk crash.  Now, as advised in ,  I first checked the offending log files using tail, no surprise there. Then, for deeper inspection, I executed this script from the .  for log in /var/log/{syslog,kern.log}; do    echo "${log} :"   sed -e 's/\[[^]]\+\]//' -e 's/.*[0-9]\{2\}:[0-9]\{2\}:[0-9]\{2\}//' ${log} \   | sort | uniq -c | sort -hr | head -10 done   The process took several hours.  The output was in the line of,   /var/log/syslog : 71209229  Rafid-Hamiz-Dell kernel:  sda3: rw=1, want=7638104968240336200, limit=1681522688 53929977  Rafid-Hamiz-Dell kernel:  attempt to access beyond end of device 17280298  Rafid-Hamiz-Dell kernel:  attempt to access beyond end of device    1639  Rafid-Hamiz-Dell kernel:  EXT4-fs warning (device sda3): ext4_end_bio:317: I/O error -5 writing to inode 6819258 (offset 0 size 4096 starting block 54763121030042024)        <snipped>  /var/log/kern.log.1 : 71210257  Rafid-Hamiz-Dell kernel:  attempt to access beyond end of device 71209212  Rafid-Hamiz-Dell kernel:  sda3: rw=1, want=7638104968240336200, limit=1681522688    1639  Rafid-Hamiz-Dell kernel:  EXT4-fs warning (device sda3): ext4_end_bio:317: I/O error -5 writing to inode 6819258 (offset 0 size 4096 starting block 954763121030042024)    (/dev/sda3 is  my home directory. As we can find,   lsblk /dev/sda NAME   MAJ:MIN RM   SIZE RO TYPE MOUNTPOINT sda      8:0    0 931.5G  0 disk  ├─sda1   8:1    0 122.1G  0 part / ├─sda2   8:2    0   7.6G  0 part [SWAP] └─sda3   8:3    0 801.8G  0 part /home    Why a process will want to write beyond the limit is actually outside the scope of my comprehension. Perhaps I will want to ask a different question in this forum if this continues even after a system update.)  Then, from  (you may want to check  for a deeper understanding), I executed,   sudo su - > kern.log > syslog   Now, these files have zero sizes. The system is running fine before and after a reboot.   I will watch these files (along with others) in the next few days and report back should they behave out-of-line.  As a final note, both  the offending files (kern.log and syslog), are set to be rotated, as inspection of the files (grep helped) inside  /etc/logrotate.d/ shows.  UPDATE 2  The log files are actually rotated. Looks like the large sizes were attained on a single day.


If in this page:   I click the "try stack overflow" login button  I go to this page:

when I try to load  it goes to the error page.


Is it possible to export layer styles to mapnik xml from QGIS?  As I understand it, it used to be possible once by means of quantumnik plug-in, which is discontinued now.  I see this issue  two years ago but to no avail.  Is that it? No other ways to do it? I refuse to believe it is not possible.  It's rather frustrating to have a map ready in QGIS and to be unable to export the styles to mapnik sitting on the same data!  You may call it a "duplicate question", but 4 years have passed since it was asked last time, so maybe something has changed?

Is it possible to export a QGIS project to Mapnik xml?   I'm using QGIS 2.4 and Quantumnik does not seem to work with that version.


Is there a word for a noun that is singular but can be used like it is plural? For example...  Q: How is your team doing? A: They are doing great.  Or  Manchester United are at the top of the league table.  Another  Liverpool have won a lot of games this season.  "Team" and "Manchester United" are both singular but they are regularly referred to like a plural. I have no idea why I fixated so much on Football based examples... I don't even like football.

I'd say Microsoft have a way of bending the rules and I know that McLaren have won the championship. While this sounds strange, I believe it is correct English (sorry, I'm not native).   But when it's a small company, would you still use it this way? Is a company always plural, or are small companies singular? I.e., would you say Bakery Johnson makes fine bread or Bakery Johnson make fine bread? Is it My book seller, Woody's, have moved or is it has moved?


Is the following use of "in case" natural in American English?     In case you can't find my house, just call me.   I'd appreciate your help.

“There are open fields over there,” he said, pointing, “in case it happens.”  “There are open fields over there,” he said, pointing, “if it happens.”    Are "if" and "in case" generally interchangeable? If not, how is 1, the original version, different from 2?


So here's my base map:    (It won't necessarily be 5x5, just using this as an example.)  It's kinda boring the way it is with all the rooms connected. I want it to be more of a randomly generated labyrinth, where every room is accessible like so:    I've tried setting the hallways randomly:  foreach(Room r) {     r.northWall = randomBoolean();     r.southWall = randomBoolean();     r.eastWall = randomBoolean();     r.westWall = randomBoolean(); }   But that almost always ends up with rooms that you're unable to go to, like this:    And often some rooms have no hallways at all. I tried saying each room must have a minimum of 2 hallways, but it still doesn't fix the problem that sometimes there an inaccessible areas.  How should I go about doing this? I'm not too worried about the speed, as long as it's not ridiculously slow (Some levels will have 100+ rooms).

What are some good resources regarding procedural content generation in the context of dungeon generation?  Closest article I could find was , which isn't quite what I'm looking for. Features, such as rooms and connected hallways, are ideal.  Thanks!


Complete Linux beginner here.    I installed Ubuntu 18.04 yesterday, dual booting with Windows 8.1.  When trying to connect to a WiFi network, it doesn't detect any of the networks (not mine or my neighbors'). I tried creating a hotspot from my Android phone and to my surprise, it detected it immediately.  I searched around on the internet and tried restarting the network manager service, changing the channel on my router, and some other things, but nothing worked.  When I boot into Windows, my wifi along with all the other networks is detected and connects with no problem.  Edit: Here's the output of running lspci -knn | grep Net -A3     captaindroid@Akash-PC:~$ lspci -knn | grep Net -A3   08:00.0 Network controller [0280]: Realtek Semiconductor Co., Ltd. RTL8723BE PCIe Wireless Network Adapter [10ec:b723]       Subsystem: Hewlett-Packard Company RTL8723BE PCIe Wireless Network Adapter [103c:804c]       Kernel driver in use: rtl8723be       Kernel modules: rtl8723be   09:00.0 Ethernet controller [0200]: Realtek Semiconductor Co., Ltd.   TL8101/2/6E PCI Express Fast/Gigabit Ethernet controller [10ec:8136] (rev 0a)

I have a HP 14-AN001NA laptop. It came with Windows 10 installed on which the Wi-Fi worked fine anywhere in the house.   However I removed Windows 10 and installed Ubuntu 16.04 instead and since I have had terrible Wi-Fi anywhere aside from about three foot away from the router. I don't know if it's relevant but my Wi-Fi is not called wlan0 but wlo1 for some reason (I didn't change it).  When running lspci -knn | grep Net -A3     I get the following output:  05:00.0 Network controller [0280]: Realtek Semiconductor Co., Ltd. RTL8723BE PCIe Wireless Network Adapter [10ec:b723] DeviceName:   Subsystem: Hewlett-Packard Company RTL8723BE PCIe Wireless Network Adapter [103c:81c1] Kernel driver in use: rtl8723be Kernel modules: wl, rtl8723be


Total Apple noob here.  I have a macbook running yosemite 10.10.5 and an iphone six.  I have some audiobooks in mp3 format on the macbook. How can I listen to these audiobooks on the iphone?  -I plug my iphone into the macbook.....it does not show up in finder  -it does show up in itunes. I dragged and dropped the mp3s into my iphones audiobooks folder in itunes. It transfers, and when done, the audiobooks library is still empty. When I use the files app on my phone it says I still have 0 files. The audiobooks then show up in my music library, and can only be accessed from apple music app (which does not play audiobooks well).  -The audiobook files do not show up on my files system on the iphone when I try to access them with third party audio book apps.  How can I achieve this?

I have an iPhone 6 that I want to use for one purpose: listen to audiobooks. When I connect the iPhone to iTunes on my PC, I can see the iPhone. But when I try to drag-and-drop an audiobook onto the phone, nothing happens (not even a "prohibited") warning.   The iTunes version is current (12.8).  iTunes is set for manual synching.  The iPhone has enough space for an audiobook or books. The iPhone does not have a SIM card.   What can I do to transfer an audiobook file to the iPhone?


So, Firefox has announced to drop NPAPI support at end of 2016. What would be an alternative for legacy sites?  For example, Google Chrome introduced Chrome Legacy Browser Support (Chrome LBS), that redirects sites using NPAPI technology. A list is maintained with the sites.  Even though, it's little more than a year since Firefox will be doing that, it's never too late to get started on something that effect the web.

Java applets are soon to be killed off forever.  I understand why we shouldn't make new ones.  But what will happen to old ones?  There are still Java applets that people may use, and there's no guarantee that anyone will be willing or able to port them to JavaScript.  For example,  has a lot of Java applets that explain and visualize certain digital audio concepts.  Another course I'm taking uses a lot of Java applets to visualize computational geometry ideas.  When Firefox drops NPAPI support, that's it, we've cut off this great reference material to all but those willing to jump through arcane technological hoops.  The following possible solutions don't always fit the bill:   Just use FireFox   Port it or rewrite it  May not be open source, or it may not be practical to do so (e.g. lack of domain knowledge). Ask the original author to do it  They may have stopped supporting it years ago.  Doesn't make it any less effective at, say, tracing out the steps for Delaunay triangulations. Find an alternative  If none exist, we're back to the second option.  If the only ones that do exist aren't browser-based, all bets are off for convenience (which is the whole point of browser apps).   Is there currently (or will there be within a year) a convenient, cross-platform way to run existing Java applets once all the major Web browsers drop NPAPI support?  Note that:   Actually so in-browser isn't critical, but it should still be cross-platform.  Ideally I wouldn't have to download extra software (after all, I already do have a JVM installed). No, I'm not suggesting we re-open the security holes that Chrome and Firefox are trying to close. If there are alternative Web browsers out there designed specifically for legacy Java applet support (or at least with no plans to drop existing NPAPI support), I would be okay with that.


I want to run some python code to access an algorithm in the processing toolbox. The result should be, that the GUI of the Algorithm pops up. (Similar to clicking on an algorithm in the Toolbox itself.)  processing.runalg('algorithm & parameters')   With this code I can run an algorithm within a script, but this is not what I am looking for. In QGIS 2.18 fTools are gone and replaced by processing-algorithms, but I doubt, that this was done using python.  So it seems possible, but is it possible with python?

I am trying to launch the UI of a processing algorithm using Python script but I cannot find a simple way for it (aside double clicking on it in the process toolbox of course). The plugin is a water network simulator and I just want to launch its pre-processing UI without using process.runalg() because this needs to enter arguments and I don't need it.  Some ways would be to trigger processes available in process toolbox or sending command to commander from python console. but I have no clue how and I am searching for 2 hours now, no results.


What is a vCard  and how do I read it? It popped up in a message from a friend and I don't know what it is. Please explain.

so someone tells me i need to call a few people.  they send me a vCard called contacts.vcf.  i import it.  i open my phone app and start to dial, but wait...i don't know their names.  How do i look up a recent vCard on my phone?  How do i know who's contact i've been sent?  when i navigate to a .vcf file, i can't open it.  all i can do is import it.  polaris office won't import/open it.  is there an android txt editor i can use to peruse a vCard?  yours truly, Confused by vCards Note 3, kit kat


When I try to import wavefront .obj, it won't show up. It appears in the explorer, but I can't see it when I try to edit. Does anybody know how to solve this?

I have opened a new blender file and deleted the default cube, then imported an obj file . I did not see any thing so i selected it and i zoomed ,nothing appears.In the outliner i saw the object name ,But in the info panel i see that there isn't any verts/faces/edges.  When i opened the obj file in a text editor i found Mesh data in it. I tired this in all blender versions (2.78c/2.78.5/7.9). Can any one help how to view the mesh?


I used fSpy to initially set up the camera in the kitchen scene I am creating. Should I place the kitchen appliances using the orthogonal grid and then tweak the fSpy camera settings to get the correct vanishing points in the scene, or should I place the appliances using a non-orthogonal grid?

I am trying to change the floor covering using a picture. How can I define the floor?


I am using Ubuntu server 16.10, XTerm and Emacs display Hebrew and Arabic script fine.  When used from within the X windowing system, the virtual console itself, that is not the terminal emulator, cannot display Hebrew.   How can it be fixed?

How can I change local console font on Ubuntu 10.04 Server to Inconsolata?


From the table of values of $\frac{2n}{n-4}$ it seems to me that the expression never evaluates to an integer for all natural numbers $n$ greater than $12$. How should I go about proving it?

I have encountered this as part of a bigger problem but I really don't know how to go on about it. I would also appreciate it if you could specify a certain technique to follow when facing such a problem.


I am planning (doing it from France) to fly from PHX to OAK with American Airlines (I am open to any other airlines, that one seems to be the typical one was readily suggested on that route, but I see there is also SW).  What surprises me is that at no stage of the reservation I am offered to add check-in luggage. There is a "check-in luggage" link, but it just opens a separate page which lists the prices.  How does this work? Should I make the reservation and then, at the airport, go to (check-in? AA booth?) and get the luggage added there?

I have booked a Ticket on American Airlines for London-Chicago for a trip in  March 2018, from the British Airways website (So that I would get BA miles on this booking).  American Airlines charges $100 for the second bag, and hence I need to pay this, since I'll be traveling with 2 checked in bags. The British Airways customer care says that I need to pay American Airlines directly for this excess baggage charge.  I went into the 'My Trips' section on the American Airlines, but I couldn't find where to pay this Excess Baggage Charge in Advance.  On the American Airlines Site, where can I pay for the Extra Bag in advance?


My attempt 1: Let $x_n=\left(1+\frac{1}{2^2} + \cdots + \frac{1}{n^2} \right)$, and we have $x_{n+1}>x_n$. Since $$ 1+\frac{1}{n^2} \le 1+ \frac{1}{(n-1)(n+1)} = \frac{n}{n-1} \cdot \frac{n}{n+1}, $$ then $ x_n < \frac{2n}{n+1} <2$. Hence $\{x_n\}_{n=2}^{\infty}$ converges. Let $$ \lim_{n \to \infty} x_n =a, $$ and notice that $x_{n+1}=\left(1+\frac{1}{(n+1)^2}\right)x_n $. By this, we can only get $a=a$. We can't know the value of $a$.  My attempt 2: We write $$ \prod_{k=2}^n \left(1+\frac{1}{k^2} \right)=\exp\left(\sum_{k=2}^n \log\left(1+\frac{1}{k^2}\right)\right) $$ So it suffices to know what's the limit of the serise on the right. I still don't know how to finish it.  Finally,I used Mathematica to calculate the limit, and it tells me that is $\frac{\sinh(\pi)}{2\pi}$. But I don't know how to know it without computer. Can you help me?

How would I go about finding $\prod_{n=1}^\infty (1+\frac{1}{n^2})$ ? Setting $a_k = \prod_{n=1}^k (1+\frac{1}{n^2})$, the first few partial products are $a_1 = 2$, $a_1 = 2.5$, $a_3 \approx 2.78$, $a_4 \approx 2.591$, $a_{20} \approx 3.50$, and they eventually appear to converge at around $3.639$. (These values were found with a quick python program. So much for my initial conjecture that the product converged to $e$.)   I tried writing $1+\frac{1}{n^2}$ as $\frac{n^2 + 1}{n^2}$, but it wasn't immediately obvious how to prove convergence / find the limit because the product doesn't really factor or telescope. Is there a way to calculate the limit?


In one of my previous questions some people commented that transformers are made to operate at certain AC frequencies. But why is that? I cannot understand the intuition behind it. Shouldn't more power be transmitted with an increase in frequency?

We have this transformer:     – Schematic created using  The power transfered to R1 resistor is maximized when the frequency of the signal is very big.This means   it is not useful to use the same circuit for low frequency signals? If I want to send a low frequency signal and want as much power as possible to be transfered to R1 resistor how do I achieve it?


In markdown, we use > to quote content. In LaTeX, how can I quote the content of a specific paper?

I need two types of citations which I have not figured out how to define:  (see highlighted in grey)     1) As Owens stated (2008, p.97), ‘the value of...’      2) Simone de Beauvoir (1972, p.365) examined her own past and wrote   rather gloomily:  The past is not a peaceful landscape lying there behind me, a country in which I can stroll wherever I please, and will gradually show me all its secret hills and dates. As I was moving forward, so it was crumbling.    I am confused about how to use \begin{quotation} or similar machineries (quote|quotation|verse|etc.) to define quotes/quotations, etc.  I use natbib (this might be irrelevant).  I would normally define a quote as \begin{quote}...\end{quote} but I find the lack of association between the quoted text and the actual bibliographic reference strange.  I don't know how to format a simple, in-text, quotation other than `blah' for single smart quotes and ``blah'' for double smart quotes.   Again, the fact that I am putting a "quote object" inside some flowing text and I am not associating it, even in a hidden way, with the bibliography database sounds strange to me.  I would find this more natural: \shortquote[BibTeX:Reference][singlesmart]{Aha!}, or something to that effect. Any help would be greatly appreciated.


I'm curious whether it is correct to replace such sentence as "There is an interesting file in the root directory" with "An interesting file is in the root directory". I think the phrases are semantically equivalent. But I am not sure that other people will understand if I say "there lives an amazing fish in my pond".  So I am trying to figure out, is there some grammatical basis for usage of the expression "there + a verb"?  This question is not a duplicate because  points to a post where common usage of the word "there" is discussed, but here I am asking about particular applying of the expression "there + a verb".

Consider the example below:     "There was a cat under the table."   There have been numerous questions asked that have involved the topic of existential constructions and the word "there" that is used in them. I would like to see some grammatical rationales that will explain what that word "there" actually is -- or is not -- in an existential construction in today's standard English.  These are some of the things that I've heard, with respect to that "there" and/or the existential construction:   "There" is the grammatical subject of the clause. "There" is a dummy pronoun.  The subject is an external complement. (optional)  An existential construction has no clausal object. (optional)  There is no such thing as a passive existential construction. (optional)   What syntactical arguments can be made for or against those above statements? And how well accepted are those above statements?  Please provide some vetted grammatical sources in your answers.


If two distinct primes p,q divides a number z, will their product $pq$ also divide z, that is $pq|z$? And how can I prove this. Thanks,

Let $a\mid c$ and $b\mid c$ such that greatest common divisor (gcd) $\gcd(a,b)=1$, Show that $ab\mid c$.


It suddenly came to my mind that this is quite strange:        Obama, with whom I was at school, has just come to live in our street.   Who are you hanging out with?      Obviously, both sentences are correct, so is "with whom".     But... why do you say "who are you hanging out with", not "whom"?

I can never figure out whether I should use who and whom. Most people use who for both colloquially, but some people say this is not correct.  What’s the rule for using who and whom correctly?


I have a web crawling script I'd like to initiate from a PHP page. It needs to run in the background and be able to be stopped from the page as well. What's the best way of accomplishing this? I know I can run shell line commands from PHP, but it seems like they would not be suitable for something that needs to keep running?

I've got a PHP script that needs to invoke a shell script but doesn't care at all about the output. The shell script makes a number of SOAP calls and is slow to complete, so I don't want to slow down the PHP request while it waits for a reply. In fact, the PHP request should be able to exit without terminating the shell process.  I've looked into the various exec(), shell_exec(), pcntl_fork(), etc. functions, but none of them seem to offer exactly what I want. (Or, if they do, it's not clear to me how.) Any suggestions?


I am creating a 3d game in Java and I want to be able to take in a players information, and save it to a text file. I understand a database would probably be more optimal, but for my own testing purposes, the text file should fit my needs. My text file includes the following:  username=kyle13524, player_health=100, player_mana=100, player_position_x=100, player_position_y=100, player_position_z=100, player_money=2149000   I am using this parsePlayerData method:  private void parsePlayerData() {      String filestring = null;     List<String> playerData = new ArrayList<String>();     ListIterator<String> li = playerData.listIterator();     try {         BufferedReader br = new BufferedReader(new FileReader("res/data/playerdata.txt"));            StringBuilder sb = new StringBuilder();         String line = br.readLine();          while (line != null) {             sb.append(line);             line = br.readLine();          }             filestring = sb.toString();       } catch (FileNotFoundException e) {         e.printStackTrace();     } catch (IOException e) {         e.printStackTrace();     }       if(filestring != null) {         String[] parts = filestring.split(",");              String[] str = null;                     for(String part : parts) {                                 playerData.add(part);         }         for(String string : playerData) {             str = string.split("=");              if(str[0] == "username") {                 PLAYER_NAME = str[1];             }             if(str[0] == "player_health") {                 PLAYER_HEALTH = Integer.parseInt(str[1]);             }             if(str[0] == "player_mana") {                 PLAYER_MANA = Integer.parseInt(str[1]);             }             if(str[0] == "player_position_x") {                 PLAYER_X = Float.parseFloat(str[1]);             }             if(str[0] == "player_position_y") {                 PLAYER_Y = Float.parseFloat(str[1]);             }             if(str[0] == "player_position_z") {                 PLAYER_Z = Float.parseFloat(str[1]);             }         }                }    }   Basically, the idea here is to have the data inputted, split into an array by the '=' and organized into static constants:  public static String PLAYER_NAME; public static int PLAYER_HEALTH; public static int PLAYER_MANA; public static float PLAYER_X; public static float PLAYER_Y; public static float PLAYER_Z; public static int PLAYER_MONEY;   The problem is that str[0] isnt being recognized as the values, yet when I print the values to the screen, they are exactly the same as what the if statements are looking for. Can anyone give me an idea as to what is going wrong here? Am I going down the right path?

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


Let $(X, A)$ be a measure space, $\mu_n: A \rightarrow [0, \infty], n \in \mathbb N$ a sequence of measures which is monotonely increasing, i.e. $\mu_n(B) \leq \mu_{n+1}(B)$ $\forall B \in A$ and all $n \in \mathbb N$.  Why is $\mu(B) := lim \mu_n(B)$ a measure on (X, A) ?

Statement  Let $(X,\Sigma,\mu)$ be a measurable space and let $(\mu_n)_{n\geq 1}$ be a sequence of measure in this space. Suppose that this is a monotone increasing sequence, in the sense that $\mu_n(E)\leq \mu_{n+1}(E)$ for all $E \in \Sigma$, and for all $n$. If we define, for every $E \in \Sigma$  $\space$  $\mu(E)=\lim_{n \to \infty} \mu_n(E)$,   prove that $\mu$ is a measure.  The attempt at a solution  I am having problems trying to prove the countable additivity property, which is, if $\{E_i\}_{i \in \mathbb N}$ is a countable collection of pairwise disjoint sets in $\Sigma$, then  $\mu(\bigcup_{i \in \mathbb N} E_i)=\sum_{i \in \mathbb N} \mu(E_i)$  In this particular case, the property is satisfied if and only if  $\lim_{n \to \infty} \mu_n(\bigcup_{i \in \mathbb N} E_i)=\sum_{i \in \mathbb N}\lim_{n \to \infty}\mu_n(E_i)$  Each $\mu_n$ is a measure, so  $\lim_{n \to \infty} \mu_n(\bigcup_{i \in \mathbb N} E_i)=\lim_{n \to \infty} \sum_{i \in \mathbb N} \mu_n(E_i)$.   How could I go on from here? I know I must use the fact that $(\mu_n)_{n \in \mathbb N}$ is a monotone increasing sequence, I would appreciate any help.


$$ y' = \frac{y}{\sin x} + \tan \frac {x}{2} $$  So from the beginning I do  $$y' - \frac{y}{\sin x} = \tan \frac {x}{2} $$ Now I should equal it to 0, shouldn't I? $$y' - \frac{y}{\sin x} = 0 $$ $$\frac{dx}{dy}   = \frac{y}{\sin x} $$ $$ dx\sin x=ydy$$ $$ \cos x=\frac{y^2}{2} $$ $$y=\sqrt{2\cos x}$$ And now i have problem with that derivative, is there any short way to do it?

$$y' = {y \over {\sin x}}+\tan{x \over 2}$$  I was trying to do this by substitution $u=y/x $ and it did not work and also with $$y' - {y \over {\sin x}} = 0$$ $${dy \over dx} = {y \over {\sin x}} $$ $${\ln(y) = \ln\left|\tan\frac{x}{2}\right|+c } $$ $${y = c\cdot\tan\frac{x}{2} } $$ but then when im trying to calculate $y'$ I have a problem and I have too many equations. Is there some easier way or am I making some mistakes.


I've read a bit about window managers, but I'm not sure if that's what I need or not. I'm using my Maverick laptop at work with an external monitor added and set so they don't mirror. I've used a Mac at work up until recently (although Linux at home) and admit that I've been a bit spoiled with their Spaces and app handling - you can, in the settings panel, indicate that a specific app should always open on a specific monitor. So, for example, I want my IDE to always open on the larger external monitor, while Thunderbird should always open on the small laptop screen.  Is there a way to do this in Ubuntu?

I have Ubuntu 14.04 and two monitors. When I open applications I need some of them to be on the primary monitor and others On the secondary. At the moment, apps always open in the primary monitor.   I have dash icons only on one (left) display, so I can't launch apps using the cursor or active window setting from Compiz.


R is a ring. $W=\left\{ x\in R|\text{x is a nilpotent}\right\}$ and $P\left( R\right) =\cap \{ P|P\unlhd A,  \text{P is prime}\}$ .How to proof  $W\subseteq P\left( R\right)$

If $\mathfrak p \subset R$ is a prime ideal, prove that for every nilpotent $r \in R$ it follows that $r \in \mathfrak p$.   The only hint that my tutor gave me was to use induction. Can someone explain what he means by this?  Thanks for the help!


MWE: \documentclass[12pt]{standalone} \usepackage[utf8]{inputenc} \usepackage[english]{babel} \usepackage[T2A]{fontenc} \usepackage{tikz} \usetikzlibrary{shapes, positioning, decorations.pathreplacing, calc} \begin{document} \begin{tikzpicture}   \tikzset{     node/.style={draw, rectangle, rounded corners},   }   \node [node] (1) {hotels\_options};    \node [node, right = 4cm of 1] (2) {hotels\_groups};    \draw (2.south) to[out=200,in=-20] (1.south);  \end{tikzpicture} \end{document}  Output:  How to add a text below the center of the curvature?

I am trying to label two curved paths connecting two nodes with labels placed at their centres using the node[midway] option. This is something that should be very simple but I have not been able to come up with something that works. Here is my MWE with my question as two comments:  \documentclass[crop,border=0]{standalone} \usepackage{tikz} \begin{document} \begin{tikzpicture}[>=latex]     \node [draw,rectangle] (Start) {Start};     \node [draw,rectangle] (Finish) [right=2cm] {Finish};     \draw [->,out=90,in=90,looseness=0.75] (Start.north) to (Finish.north);     % I want to label this path using [midway,below] as {forward}     \draw [->,out=-90,in=-90,looseness=0.75] (Finish.south) to (Start.south);     % I want to label this path using [midway,above] as {reverse} \end{tikzpicture} \end{document}   Can someone please point me in the right direction.  I also appreciate comments to improve code elegance or simplicity.  Thank you.


I have to change /proc/sys/kernel/yama/ptrace_scope value in order to use gdb attach. Whenever I change it with sudo nano or sudo gedit, it says: no permission or gives me an error and when I restart my PC it resets back to 2.

As the question says, I need to edit my /proc/acpi/wakeup file, but when I open it with any text editor, it shows blank file. cat command, on the other hand, displays correct file contents in terminal. When I navigate to that file in file manager, it says it's size is 0 bytes. I'm using Xubuntu 15.04. I'm thoroughly confused.


I am new to Ubuntu 14.04. I have installed KDE recently.I don't know how to uninstall/remove it.  It displays an error message and I want to switch back to default Unity Desktop Environment. How to change to default through terminal?  I want to definitely know because I could not open any application (including my files/folders) other than terminal (for which I know the shortcut). I want to switch back to Unity badly.  In the xsessions command in terminal it displays ubuntu.desktop and kubuntu-plasma.desktop; But when I try to remove it shows: no such package is there.

I have 2 computers with Ubuntu but on both I installed KDE to have another option for the users. Since Unity has come along very well, there has not been a need to use KDE for a while now. How can I delete all KDE related packages with one single sweep, freeing space and anything KDE related in Ubuntu, including overwriting the Logo of ubuntu when the PCs start or shutdown since after installing KDE the Kubuntu logo is the default one. How to revert back completely from all KDE stuff with a simple short command line or GUI tool.  NOTE - I ask this because it is very time consuming to start selecting, one by one, each package that relates to the KDE desktop environment, checking if it also relates to any GTK, checking dependencies for each, etc.. Deleting the package kubuntu-desktop does not remove every installed KDE package that was installed with it since this is a pseudo package that installs the rest of the real packages but does not uninstall them which makes me wonder why a package can install a whole bunch of other packages but not uninstall them with some added option to actually uninstall them not just the dummy package itself.


For the equation:  The indefinite integral of $\frac{1}{x^4+1}$ My question is, without partial fractions to turn this into "integrable" form what can I do?   Is it algabraically possible to manipulate this to fit any of the standard integration rules?  Possibly letting $u=x^2$, giving $\frac{1}{u^2+1}$.  Thanks

I don't know how to integrate $\displaystyle \int\frac{1}{x^{4}+1}\mathrm dx$. Do I have to use trigonometric substitution?


Gparted shows the following warning about a partition.  9.23 GiB of unallocated space within the partition.  To grow the file system to fill the partition, select the partition and choose the menu item:  Partition --> Check  After attempting to do that check and repair operation in gparted I get the following error:   http://www.w3.org/1999/xhtml' xml:lang='en-US' lang='en-US'>   GParted Details    GParted 0.25.0 --enable-libparted-dmraid --enable-online-resize  Libparted 3.2     Check and repair file system (ext4) on /dev/sdb2  00:00:00    ( ERROR )             calibrate /dev/sdb2  00:00:00    ( SUCCESS )             path: /dev/sdb2 (partition)start: 125001end: 33681407size: 33556407 (16.00 GiB)          check file system on /dev/sdb2 for errors and (if possible) fix them  00:00:00    ( ERROR )             e2fsck -f -y -v -C 0 /dev/sdb2  00:00:00    ( ERROR )                    e2fsck 1.42.13 (17-May-2015)/dev/sdb2 has unsupported feature(s): metadata_csume2fsck: Get a newer version of e2fsck!              ========================================    I used this command to install e2fsck sudo apt-get install e2fs*

I have a desktop computer with Ubuntu Desktop 14.04.4 LTS 64-bit with an attached HDD USB 3.0 4TB Intenso 1 partition ext4 data drive only (no OS or Apps). After a sudden power failure, I am unable to mount the drive (checked different host Linux machines with no result).  error message:  sudo mount /dev/sdd1 /mnt mount: wrong fs type, bad option, bad superblock on /dev/sdd1,        missing codepage or helper program, or other error        In some cases useful info is found in syslog - try        dmesg | tail  or so   Tried with fsck, e2fsck with no result. The error message says "Get a newer version of e2fsck".  Tried with all available superblocks backups with no result.  Tried offline file/drive Linux checkers on the offline and UNmounted volume with no result.  Finally, I received the following error message for which I couldn't find any help online:   "has unsupported feature(s): metadata_csum". e2fsck 1.42.9 (4-Feb-2014) /dev/sdd1 has unsupported feature(s): metadata_csum e2fsck: Get a newer version of e2fsck!   Can anyone help me take my data back?


I have been working on my probability. I have "possibly" memorized how to solve but, I really like to understand it with my heart. But.. I am kinda stuck.   I am trying to find out the possible outcomes of four of kind (unordered)  Here is my intuition:  $$\frac{52 \cdot 3 \cdot 2 \cdot 1 \cdot 48}{5!}$$   I do not see why this is wrong.   Please help me out!

Question What is the probability that a ﬁve-card poker hand contains "four of a kind hand"? For More information about poker's four of a kind hand,please refer  My Attempt $\text {Rank of card-: Jack,King,Queen,Ace}$$,9,8,...1$ In four of a kind hand , $4$ cards are of the same rank( and obviously of diiferent type) $\Rightarrow$ Now in a set of $52$ card,we have $13$ ranks of $4$ kind(spade,heart,diamond,club) $\Rightarrow$ four of a kind hand says  $4$ cards are of the same rank. So Among $13$ ranks ,select $1$ of the rank i.e $\binom{13}{1}$, and the remaining last card can be any thing I am not getting how to move forward ,please help me out. Thanks in advance


I have an exercise in my notebook, which i'm not sure if i'm doing it right. Exercise: Show that if $X$ is equipped with the discrete metric $d$ then every subset of $X$ is both open and closed. Definition of discrete metric: $d(x,x)=0$ and $d(x,y)=1$ if $x\neq y$ My approach: Take an arbitrary set $A\subset X$. Take a closed ball $\overline{B}(x,\epsilon)=\{y\in X: d(x,y)\leq \epsilon\}\subset A$ such that $\epsilon=1$. Now, take points all points $x'\in \overline{B}$ such that $d(x,\epsilon)=0$. These points $\{x'\}$ are then open sets by themselves since $\forall x\in\{x'\} \exists \epsilon=1/2$  such that $B(x,\epsilon)\subset \{x'\}$. Therefore $B(x,\epsilon)\subset\{x'\}\subset \overline{B}(x,\epsilon)$. Hence by definition $\overline{B}(x,\epsilon)$ is open. Since $A=\cup_{i=1}^n \overline{B}(x,\epsilon)$, it follows that $A$ is a union of both closed and open balls. Hence it's both closed and open. Would this be correct?

I need to prove that in a discrete metric space, every subset is both open and closed. Now, I find it difficult to imagine what this space looks like. I think it  consists of all sequences containing ones and zeros.   Now in order to prove that every subset is open, my books says that for  $A \subset X $, $A$ is open if $\,\forall x \in A,\,\exists\, \epsilon > 0$ such that $B_\epsilon(x) \subset A$.  I was thinking that since $A$ will also contain only zeros and ones, it must be open. Could someone help me ironing out the details?