My problem is this:  If an Account has no Contacts, then the first created contact by default becomes the primary and that value should be set in reference. If the primary contact is deleted, the next available contact, if there is any, should be the primary contact and the relationship on account should reflect this. If all contacts are deleted, the primary contact reference on Account will be blanked out.  Here is my code so far:  public class CreatePrimaryContactHandler {     public static void createPrimary(List<Account> accounts){       Set<Id> accountIds = new Set<Id>();       List<Account> updatedAccounts = new List<Account>();       List<Contact> con = new List<Contact>();       for (Contact c : con) {         accountIds.add(c.AccountId);       }        Map<Id,Account> accountMap = new Map<Id,Account>([Select Id, Primary_Contact__c, (Select Id, Name from Contacts where IsPrimary__c = true) from Account where Id in :accountIds]);         for (Contact c : Trigger.new) {         if (c.IsPrimary && accountMap.get(c.AccountId)) {             Account updAccount = accountMap.get(c.AccountId);             updAccount.Primary_Contact__c = c.Id;             if (updAccount.Contacts != null && updAccount.Contacts.size()>0) { // This will identify if account already has primary contact set               // Not sure what you want to do? Throw an error? or turn off the iS Primary on older contact?             }              updatedAccounts.add(updAccount);         }        }        update updatedAccounts;     }  }   Trigger:  trigger CreatePrimaryContact on Contact (after insert, after update){     CreatePrimaryContactHandler.createPrimary(); }

The function of this apex code is when Account has no Contacts the first contact created become the primary contact and when there is existing primary contact it cannot assign a other primary contact on account. Please help to optimized my code to easy understand.Thanks for the help.  public class CreatePrimaryContactHandler {     public static void createPrimary(List<Contact> contactList)     {        Set<Id> accountId = new Set<Id>();         for(Contact c : contactList)         {             accountId.add(c.AccountId);         }         List<Contact> allContact = [SELECT Id, Account.Id, Primary_Contact__c FROM Contact WHERE (Account.Id IN : accountId)];         Map<Id, List<Contact>> acctContactMap = new Map<Id, List<Contact>>();             for(Id aId : accountId)             {              List<Contact> conList = new List<Contact>();                 for(Contact allcont : allContact)                 {                     if(allcont.AccountId == aId)                     {                     conList.add(allcont);                     }                 }                 acctContactMap.put(aId, conList);             }             for(Id accId : acctContactMap.keySet())             {                 Integer count = 0;                 for(Contact c : contactList)                 {                     if(c.AccountId == accId && c.Primary_Contact__c)                     {                         count++;                     }                 }                 if(count <= 1)                 {                     List<Contact> cList = acctContactMap.get(accId);                     Contact primary;                     Boolean isPrimary = false;                     for(Contact cont : cList)                     {                         if(cont.Primary_Contact__c)                         {                             isPrimary = true;                         }                     }                     for(Contact cont : contactList)                     {                         if(cont.AccountId == accId)                         {                             if(cont.Primary_Contact__c)                             {                                 if(primary != null)                                 {                                     primary.Primary_Contact__c = false;                                      isPrimary = false;                                 }                                 else if(isPrimary)                                 {                                 cont.addError('Invalid Primary Contact. This Account has already an existing Primary Contact.');                                 }                                     else                                     {                                         cont.Primary_Contact__c = true;                                         isPrimary = true;                                     }                             }                                    else if(!isPrimary)                                 {                                     cont.Primary_Contact__c = true;                                     isPrimary = true;                                     primary = cont;                                 }                         }                     }                 }                 else                 {                     contactList.get(0).addError('Invalid Primary Contact. This Account has already an existing Primary Contact.');                 }         }       } }   This is the Trigger  trigger CheckPrimaryContact on Contact (before insert,after update,before update){     if(trigger.IsInsert && trigger.IsBefore){         CreatePrimaryContactHandler.createPrimary(trigger.new);     }     if(trigger.IsBefore && trigger.IsUpdate){         CreatePrimaryContactHandler.createPrimary(trigger.new);     } }


I have a server that will have 2 different types/formats of requests coming in. Both request URL's will start with: http://myredirect.mycompany.com/browse/. After '/browse/' it will either be a number:  http://myredirect.mycompany.com/browse/12345, it can be any number  or it will be 2 to 4 capital letters followed by a '-' followed by a number:   http://myredirect.mycompany.com/browse/QA-12345  What I want to do redirect to a different URL that's based on the incoming URL. For example:  http://myredirect.mycompany.com/browse/12345 would redirect to http://serverA.mycompany.com/show_item.cgi?12345   and  http://myredirect.mycompany.com/browse/QA-12345 would redirect to http://serverB.mycompany.com/browse/QA-12345   I think what I want is to use an nginx rewrite but I'm not sure how to form. From what I've googled, you can use regex in rewrites so I could use something like  ^(/browse/[0-9])?   for the first one. But how do I actually pull that number into the redirect URL? Thanks!

I've been working with Apache http servers for quite some time, and finally making the move to static-content servers alongside the others dynamic-content machines.   I was wondering, does nginx support ".htaccess" files, and things like mod_rewrite?   As I'm very used to the syntax, I was wondering what the (syntax) differences were, and what the learning curve is like moving from Apache configs to nginx.


To decide whether a propositional formula $P$ is classically provable, the completeness theorem gives an easy algorithm : simply test all finite boolean combinations of the variables of $P$. It is exponential in the number of variables, but it does finish in all cases.  Now completeness for constructive proofs means that we must test all evaluations of the variables of $P$ into all Heyting algebras, not just $\{0,1\}$. The open sets of $\mathbb{R}$ form such a Heyting algebra, which is infinite. So is there a constructive decision algorithm ?

Is intutionistic propositional logic decidable?  If so, what is a decision procedure for it, like tableaux for classical propositional logic?  EDIT: In the first revision I mistook "predicate" for "propositional".


I have a challenge getting a query i saved into the database. On my project, i want to save mysql update query in the database, and when another action is run on a different page, i get that query and pass it through my function and it runs. However after getting it its empty. Below is what i have done so  far.  //Saving the query in database  $query = array(); $query['approved'] = "UPDATE payment SET pm_status = 'Approved' WHERE id = '69'"; $query['approved2'] = "UPDATE member SET pay_date = NOW())";   //i den serialize and addslashes so it can be saved in the database  $tosave = addslashes(serialize($query)); $sql = "INSERT INTO trans (saved_query) VALUES ($tosave)";   // I den save $tosave into the database, which i checked and it was saved. On the page i want to use it, each time i get the value and unserialize, it returns as empty e.g after selecting the value to a row  $toprocess = unserialize($query['saved_query']); echo $toprocess['approved'];   it returns an empty value, and when i run it in a query it doesn't run.  but if i echo directly without unserializing, it dispplays the values in it  echo $query['saved_query'];   Pls help incase i am missing something here. Thanks  I am not preventing an sql injection. I had dont that already. I just want to run the sql saved into the database. This is different to the answers in the prevention of mysql injection. Thanks

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


If the bisector of $\angle A$ in triangle $ABC$ meets $BC$ at $U$, prove that $AU^2=bc(1-a^2/(b+c)^2)$. (Where a, b, c are sides opposite to $A, B, C$ respectively).   I am not able to do anything. A hint to solve this in pre college level will be appreciated.

How do I prove that a triangle with sides a, b, c, has an angle bisector (bisecting angle A) is of length:   $$\frac{2 \sqrt{bcs(s-a)}}{b+c}$$  I have tried using the sine and cosine rule but have largely failed. A few times I have found a way but they are way too messy to work with.


I have a vector layer, and bunch of lat/lon values. I want to put markers on the vector layer for each lat/lon pair. I have never used QGIS, would you help with it.

How do I create point features with exact (manually entered) coordinates in QGIS? I get precise GPS coordinates from a survey team which I need to add to a point layer. What I want: add point, type in the coordinates and when pressing enter the point is created where it is supposed to be.


I have a 17" laptop with Intel 6700HQ and Nvidia 950M inside (ASUS N752VX).  When I boot Windows, it starts with native resolution of the display which is 2560x1440. On Ubuntu, I can't go over 1920x1080.  My nvidia settings are like this     I can't change the Virtual Size from here and I don't see any line to change on xorg.conf.  These are my display settings     The resolution drop down menu doesn't go above 1080p.

I am new to Ubuntu. I have installed Ubuntu 12.04 and am stuck trying to set up the correct resolution for my LCD display.  The native resolution for the LCD is 1920x1080  here is the output from xrandr:  $ xrandr Screen 0: minimum 320 x 200, current 1280 x 720, maximum 4096 x 4096 LVDS1 connected 1280x720+0+0 (normal left inverted right x axis y axis) 0mm x 0mm 1280x720 60.0*+ 800x600 60.3 56.2  640x480 59.9 VGA1 disconnected (normal left inverted right x axis y axis)   Then I create new modeline:  $ cvt 1920 1080 60 1920x1080 59.96 Hz (CVT 2.07M9) hsync: 67.16 kHz; pclk: 173.00 MHz Modeline "1920x1080_60.00" 173.00 1920 2048 2248 2576 1080 1083 1088 1120 -hsync +vsync   So far so good. Then I create new mode using xrandr:  $ xrandr --newmode "1920x1080_60.00" 173.00 1920 2048 2248 2576 1080 1083 1088 1120 -hsync +vsync   But for some reason that new mode was created for VGA (VGA1) output instead of LCD output (LVDS1):  $ xrandr Screen 0: minimum 320 x 200, current 1280 x 720, maximum 4096 x 4096 LVDS1 connected 1280x720+0+0 (normal left inverted right x axis y axis) 0mm x 0mm 1280x720 60.0*+ 800x600 60.3 56.2  640x480 59.9  VGA1 disconnected (normal left inverted right x axis y axis) 1920x1080_60.00 (0xbc) 173.0MHz <---------- ????!!!!!! h: width 1920 start 2048 end 2248 total 2576 skew 0 clock 67.2KHz v: height 1080 start 1083 end 1088 total 1120 clock 60.0Hz   So, if I try to add mode to LVDS1, I get an error:  $ xrandr --addmode LVDS1 "1920x1080_60.00" X Error of failed request: BadMatch (invalid parameter attributes) Major opcode of failed request: 149 (RANDR) Minor opcode of failed request: 18 (RRAddOutputMode) Serial number of failed request: 25 Current serial number in output stream: 26   Adding that new mode to VGA1 works fine, but I don't use that VGA1 output.


I have tried to install the Polarr photo editor 1/2 dz times either from the software or snap all have failed. Software center looks like it has installed but will not launch. Using snap it fails to even install with this error message:  sudo snap install polarr error: cannot perform the following tasks: - Fetch and check assertions for snap "polarr" (9) (Get https://api.snapcraft.io/api/v1/snaps/assertions/snap-revision/7Gj-KkZig4Fq41jE0onllCWjATUViyNVmRySSFi1xpQlTiLQZQgK_iQleURBAOTY?max-format=0: net/http: request canceled (Client.Timeout exceeded while awaiting headers))   The link is no help. I tried emailing support and get this;//support@polarr.co (after RCPT TO): 550-5.1.1 The email account that you tried to reach does not exist.

I'm unable to install snap in Ubuntu 16.04, instead, I get the error shown below:  dheer@dheer-Inspiron-3558:~$ sudo snap install notes   [sudo] password for dheer:  *********  error: cannot perform the following tasks: - Fetch and check assertions for snap "ubuntu-core" (423) (Get https://assertions.ubuntu.com/v1/assertions/snap-revision/7sS9MbzjeZ87E4IVq3ByrAO8t1YqriNlaX4r7eT5AHYZjzRCa7twTmWU53e6falH: net/http: request canceled while waiting for connection (Client.Timeout exceeded while awaiting headers)) dheer@dheer-Inspiron-3558:~$    Please help?


Is it possible to project an image into the eye, without wearing glasses or using a projection screen, which:   Appears to be on a focal plane in front of rather than behind the source Appears larger in width/height than the source   The image doesn't need to be truly volumetric, appear when viewing from the side, appear to anyone other than the user, or display true black. Less ambitious than R2D2 :) Goal: take a smartphone-size device out of my pocket, put it on a cafe table, look down and see a floating image larger than the device.  Side view (image only visible to eye, not visible to person to the side):   Example: smartphone with pseudo 3D using eye tracking and parallax:

Is there some law of physics that strictly prohibits the projection of 2D or 3D images into thin air (such as holograms in movies) or is a solution to achieve this still up for grabs by an eventual discoverer?


I've been using Linux for about 4 weeks now, more specifically Ubuntu. I wanted to find the remaining disk space I have left and was told that the df command will give me all the information I need to answer that question but there is quite a lot of information there. I was just looking for a simple response such as 225gb out of 500gb used etc but instead I get a lot more information.     Filesystem      Size  Used Avail Use% Mounted on udev            3.9G     0  3.9G   0% /dev tmpfs           788M  1.9M  786M   1% /run /dev/sda5       104G   15G   84G  15% / tmpfs           3.9G     0  3.9G   0% /dev/shm tmpfs           5.0M  4.0K  5.0M   1% /run/lock tmpfs           3.9G     0  3.9G   0% /sys/fs/cgroup /dev/loop0       56M   56M     0 100% /snap/core18/1988 /dev/loop2      256M  256M     0 100% /snap/gnome-3-34-1804/36 /dev/loop3      219M  219M     0 100% /snap/gnome-3-34-1804/66 /dev/loop1       56M   56M     0 100% /snap/core18/1944 /dev/loop4       65M   65M     0 100% /snap/gtk-common-themes/1514 /dev/loop6       32M   32M     0 100% /snap/snapd/11036 /dev/loop5       50M   50M     0 100% /snap/snap-store/467 /dev/loop7       63M   63M     0 100% /snap/gtk-common-themes/1506 /dev/loop8       33M   33M     0 100% /snap/snapd/11107 /dev/loop9       52M   52M     0 100% /snap/snap-store/518 /dev/sda2        96M   33M   64M  35% /boot/efi tmpfs           788M   56K  788M   1% /run/user/1000  Above is the output to df -h, so a few questions. Why is there so many different options showing such as udev,tmpfs, dev/loop9 etc, what are these? I am guessing that /dev/sda5 is my Linux partition, the only reason I determined this was because it has the most space used and most space available, is everybody's Linux partition (main partition where data is stored) named /dev/sda5? and why is there another /dev/sda in the name /dev/sda2? I'm also quite unsure what the Use% Mounted On column is for, why is there folders listed in this column? Thanks

I would like you to help me understand the output of df -h below:  udev            7,8G     0  7,8G   0% /dev tmpfs           1,6G  1,7M  1,6G   1% /run /dev/sda3       229G   68G  150G  32% / tmpfs           7,9G  211M  7,6G   3% /dev/shm tmpfs           5,0M  4,0K  5,0M   1% /run/lock tmpfs           7,9G     0  7,9G   0% /sys/fs/cgroup /dev/loop1       84M   84M     0 100% /snap/core/3748 /dev/loop0      160M  160M     0 100% /snap/spotify/5 cgmfs           100K     0  100K   0% /run/cgmanager/fs tmpfs           1,6G   68K  1,6G   1% /run/user/1000   I would like to understand what exactly are the udev, tmpfs and /dev/loop partitions.   I am wondering if they are some sort of 'leftoveres' after my Virtual Machines in Virtual Box.   I had a few virtual machines with 8GB in size but I have removed them and I still see there are some partitions that are taking quite a lot of space.    Are they related to Virtual Box?  Is it safe to remove those partitions?


In other words: How to control a value (that doesn't have a socket) in a node inside a Node Group using this Node Group's Group Input.  I'm guessing somehow drivers need to be involved, haven't found info on this though.  Example: Driving a Size property from Map Value node from a Group Input of the Node Group the Map Value node is in.

Sometimes I create Material Groups to be used as appendable reusable assets. Unfortunately sometimes parameters I want to control using a Group Node's slider are not available for routing to a Group Node's input socket. Some examples of these are the Color Ramp and the Mapping Node.  So here's what I want to do:    Can this be done? If so, how?  Thanks!


I can understand the Heisenberg Uncertainty Principle which states that $$\Delta{x}\Delta{p_x}\ge \hbar/2$$ I also understand that this can be extended to any canonical conjugates. But I can't seem to understand the Time-Energy Uncertainty Principle. Where does it have its origin? Does the Heisenberg Uncertainty principle support it (in which case I would like to see an elegant derivation) or is it an independent principle in itself? Also, how do we interpret this? In measurement theory people seem to say that any energy measurement has an uncertainty that has to do with the duration of measurement, Atomic/Molecular physicists say that spectral energy has an error that has to do with the lifetime of the excited states and so on. It seems to me that people are randomly interpreting the Time-Energy Uncertainty anywhere time and energy come together. What is the mathematical basis of such an interpretation? And can it be literally used anywhere where energy and time come together - which is everywhere?

In non-relativistic QM, the $\Delta E$ in the time-energy uncertainty principle is the limiting standard deviation of the set of energy measurements of $n$ identically prepared systems as $n$ goes to infinity. What does the $\Delta t$ mean, since $t$ is not even an observable?


I have this equation:  $3^x + 4^x = 5^x$, according to , $x <= 2$, so the answer is $2$.  But how can I get to the result through an elementary algebraic procedure?  I have tried many things, but I have not come up with any concrete results, arriving only at:  First try, $log(3^x+4^x) = 3log5$  Second try, $(\frac{3}{5})^x + (\frac{4}{5})^x = 1$  I have also tried to search several programs, such as symbolab, mathway, etc. But, they have not been able to solve it, the only program that has given me an answer is wolframAlpha, but I can not visualize it step by step, thanks in advance.

I would like to prove that the equation $ 3^x+4^x=5^x $ has only one real solution ($x=2$)  I tried to study the function $ f(x)=5^x-4^x-3^x $ (in order to use the intermediate value theorem) but I am not able to find the sign of $ f'(x)= \ln(5)\times5^x-\ln(4)\times4^x-\ln(3)\times3^x $ and I can't see any other method to solve this exercise...


Hello, I am currently working on a 3D scene and this has happened to me several times by now and I still haven't found a solution. Increasing light bounces or samples doest seem to work. This rendder has 215 samples and MIN 4 light bounces, max 4 light bounces.

Since the Denoise feature was added to Blender I only use the default setting with it and it really does the work. But sometimes the denoise is noticable on some of my renders. How can I overcome the blurred effect? Denoising for me is a big help because my system is quite aged.


A polynomial $P(x)$ of $n$ degree satisfies $P(k)=2^k$ for $k = 0,1,2,3......,n$.  Find the value of $P(n+1)$.  How can I proceed in solving such problems.

For a polynomial $P(x)$ of degree $n$, $P(k) = 2^k$ for $k = 0, 1, 2, . . . , n$. Find $P(n+1)$.   If $n=1$, $P(x)=x+1$ and $P(2)=3$.  If $n=2$, $P(x)=0.5x^2+0.5x+1$ and $P(3)=7$.  How to approach further cases? I am stuck.


I am pretty new in WP (I came from Joomla) and I am finding some difficulties in the migration of an old WP website (made inWP 3.5) on my local web server.  I have performed the following operation:   I have put the website backup into a directory named blog into my Apache www directory on my Ubuntu local system. Then I have put the database backup on my MySql local server Finally I have change the values in the wp-config.php file to use my local DB   The problem is that when I try to open the URL:  http://localhost/blog/   to see the website I see noting (a white screen)  Inside the wp-config.php I have activated the debug mode by the line:  define('WP_DEBUG', true);   and I have no errors, so I think that this is not a DB problem.  Inside the Apache error log file (/var/log/apache2/error.log) I found that the following errors occurs:  [Fri Jan 10 22:04:50 2014] [notice] Apache/2.2.22 (Ubuntu) PHP/5.3.10-1ubuntu3.9 with Suhosin-Patch configured -- resuming normal operations [Fri Jan 10 22:05:08 2014] [error] [client 127.0.0.1] PHP Warning:  require_once(/var/www/blog/wp-load.php): failed to open stream: No such file or directory in /var/www/blog/wp-blog-header.php on line 12 [Fri Jan 10 22:05:08 2014] [error] [client 127.0.0.1] PHP Fatal error:  require_once(): Failed opening required '/var/www/blog/wp-load.php' (include_path='.:/usr/share/php:/usr/share/pear') in /var/www/blog/wp-blog-header.php on line 12 [Fri Jan 10 22:38:37 2014] [error] [client 127.0.0.1] PHP Warning:  require_once(/var/www/blog/wp-load.php): failed to open stream: No such file or directory in /var/www/blog/wp-blog-header.php on line 12 [Fri Jan 10 22:38:37 2014] [error] [client 127.0.0.1] PHP Fatal error:  require_once(): Failed opening required '/var/www/blog/wp-load.php' (include_path='.:/usr/share/php:/usr/share/pear') in /var/www/blog/wp-blog-header.php on line 12 [Fri Jan 10 22:38:38 2014] [error] [client 127.0.0.1] PHP Warning:  require_once(/var/www/blog/wp-load.php): failed to open stream: No such file or directory in /var/www/blog/wp-blog-header.php on line 12 [Fri Jan 10 22:38:38 2014] [error] [client 127.0.0.1] PHP Fatal error:  require_once(): Failed opening required '/var/www/blog/wp-load.php' (include_path='.:/usr/share/php:/usr/share/pear') in /var/www/blog/wp-blog-header.php on line 12 [Fri Jan 10 22:38:39 2014] [error] [client 127.0.0.1] PHP Warning:  require_once(/var/www/blog/wp-load.php): failed to open stream: No such file or directory in /var/www/blog/wp-blog-header.php on line 12 [Fri Jan 10 22:38:39 2014] [error] [client 127.0.0.1] PHP Fatal error:  require_once(): Failed opening required '/var/www/blog/wp-load.php' (include_path='.:/usr/share/php:/usr/share/pear') in /var/www/blog/wp-blog-header.php on line 12 [Fri Jan 10 22:38:40 2014] [error] [client 127.0.0.1] PHP Warning:  require_once(/var/www/blog/wp-load.php): failed to open stream: No such file or directory in /var/www/blog/wp-blog-header.php on line 12 [Fri Jan 10 22:38:40 2014] [error] [client 127.0.0.1] PHP Fatal error:  require_once(): Failed opening required '/var/www/blog/wp-load.php' (include_path='.:/usr/share/php:/usr/share/pear') in /var/www/blog/wp-blog-header.php on line 12   Reading online it seems to me that I also have to change the values of the home and siteurl fields into the wp_options database table (they contained references to the site on the old server), so I have change it with these values:   home: http://localhost/blog siteurl: http://localhost/blog   But the problem persist (I always see a white screen).  I think that maybe the problem could be that these value are wrong, or maybe I have change some other values? Or maybe I also create a specific .htacces file into my blog directory? (now I have no .htaccess file)  Do you have some idea about how to solve this problem?  Tnx  Andrea

I am pretty new to WP (I came from Joomla) and I am finding some difficulties trying to put on my local web server an old backup of a website (made using WP 3.5)  I have performed the following operation:  1) I have put the website backup into a directory named blog into my Apache www directory on my Ubuntu local system.  2) Then I have put the database backup on my MySql local server  3) Finally I have change the values in the wp-config.php file to use my local DB  The problem is that when I try to open the URL to see the website I see noting (a white screen)  Into the Apache log file (/var/log/apache2/error.log) I found the following errors messages:  [Fri Jan 10 22:04:50 2014] [notice] Apache/2.2.22 (Ubuntu) PHP/5.3.10-1ubuntu3.9 with Suhosin-Patch configured -- resuming normal operations [Fri Jan 10 22:05:08 2014] [error] [client 127.0.0.1] PHP Warning:  require_once(/var/www/blog/wp-load.php): failed to open stream: No such file or directory in /var/www/blog/wp-blog-header.php on line 12 [Fri Jan 10 22:05:08 2014] [error] [client 127.0.0.1] PHP Fatal error:  require_once(): Failed opening required '/var/www/blog/wp-load.php' (include_path='.:/usr/share/php:/usr/share/pear') in /var/www/blog/wp-blog-header.php on line 12 [Fri Jan 10 22:38:37 2014] [error] [client 127.0.0.1] PHP Warning:  require_once(/var/www/blog/wp-load.php): failed to open stream: No such file or directory in /var/www/blog/wp-blog-header.php on line 12 [Fri Jan 10 22:38:37 2014] [error] [client 127.0.0.1] PHP Fatal error:  require_once(): Failed opening required '/var/www/blog/wp-load.php' (include_path='.:/usr/share/php:/usr/share/pear') in /var/www/blog/wp-blog-header.php on line 12 [Fri Jan 10 22:38:38 2014] [error] [client 127.0.0.1] PHP Warning:  require_once(/var/www/blog/wp-load.php): failed to open stream: No such file or directory in /var/www/blog/wp-blog-header.php on line 12 [Fri Jan 10 22:38:38 2014] [error] [client 127.0.0.1] PHP Fatal error:  require_once(): Failed opening required '/var/www/blog/wp-load.php' (include_path='.:/usr/share/php:/usr/share/pear') in /var/www/blog/wp-blog-header.php on line 12 [Fri Jan 10 22:38:39 2014] [error] [client 127.0.0.1] PHP Warning:  require_once(/var/www/blog/wp-load.php): failed to open stream: No such file or directory in /var/www/blog/wp-blog-header.php on line 12 [Fri Jan 10 22:38:39 2014] [error] [client 127.0.0.1] PHP Fatal error:  require_once(): Failed opening required '/var/www/blog/wp-load.php' (include_path='.:/usr/share/php:/usr/share/pear') in /var/www/blog/wp-blog-header.php on line 12 [Fri Jan 10 22:38:40 2014] [error] [client 127.0.0.1] PHP Warning:  require_once(/var/www/blog/wp-load.php): failed to open stream: No such file or directory in /var/www/blog/wp-blog-header.php on line 12 [Fri Jan 10 22:38:40 2014] [error] [client 127.0.0.1] PHP Fatal error:  require_once(): Failed opening required '/var/www/blog/wp-load.php' (include_path='.:/usr/share/php:/usr/share/pear') in /var/www/blog/wp-blog-header.php on line 12   Why? what could be the problem? How can I try to solve it?  Tnx  Andrea


$r$ is a number such that $r=p^a$. If the sum of some fractions equal to $1$ and one of the denominators is divisible by $r$ then there is another denominators that is exactly divisible $r$.  It seems to be really easy but I cannot prove it for example:  $\frac{7}{12}+\frac{4}{15}+\frac{3}{20}=1$  You can see here we have two denominators that are divisible by $4$ or two denominators that are divisible by $3$.Any hints?

prove if we want that the sum of some fractions be $1$ and the denominators of one of them is $d$ then another denominators should divisible by $d$ or $d$ should be divisible to another denominators.  It seems to be easy I tried to prove it.I first tried some cases.  $1=\frac{1}{2}+\frac{1}{3}+\frac{1}{6}$  Here we can see that $6$ is divisible by $3$. Also here $6$ is divisible by $2$ .But I want to prove one of the denominators but here two of them is possible.After trying a lot I cannot found any proofs.Any hints?  update1: the numerator should be prime


For example someone asks a question and then accepts an answer a few minutes later.

Why is there a 15 minute time limit on accepting an answer in StackOverflow?


When I installed Ubuntu dual boot on my windows machine, I just did a 10 GB partition for installing the dual boot. But later I realized that I need much more than just 10 GB. Is it possible to just extend the disc space without uninstalling and reinstalling Ubuntu?

Previously, I have installed Windows 7 on my 320 GB laptop with three partitions 173, 84 and 63 GB each. The 63 GB partition was where the Windows was installed. The rest were for file containers.  Now I changed my OS to Ubuntu 12.04 LTS. I installed Ubuntu by replacing the entire Windows 7 on the 63 GB partition. The rest of the partitions remain as an NTFS Windows partition and I can still access them both (the 173 and 84 GB partitions).  Now I want to change the two partitions of Windows into an Ubuntu format partitions plus most importantly, I want to extend the 63 GB partition to more than a 100 GB because at the moment I am running out of disk space. Whenever I try to install any application, especially using wine, it always complains for a shortage of disk space.  How do I do the extending activity before I entirely format my laptop again and lose all the important files on my partitions?


I originally thought that saving my images as TIFs from PS was degrading my image quality until I realized that my RAW files were coming into PS that way.  So I looked into it further and found that my CR2 files (from my Canon 7D Mk II) didn't look as good once brought into Camera Raw, which I'm using with PS CS6.  So once in Camera Raw the image had more noise than the RAW image.  Is there something I'm doing wrong (can't imagine because I'm simply opening the file and not making any adjustments), or is there a different way that I can get a clean RAW file into PS for editing?  Thanks in advance for your feedback!  Anthony

I've found that when you load a RAW image into an editing program such as Lightroom/Aperture, the image is usually worse than if you just took the image as JPEG. Now I understand that the camera does some magic during the JPEG conversion. But I'm trying to understand what that "magic" is.   If I'm looking to implement that "magic" myself on the desktop, what kind of settings should I be trying? I find that the RAW files have more extreme contrast. The dark areas for example are way darker than JPEG. Why is this? And what is the best way to fix this?


Consider the question   Asymptotic notation questions have been pretty standard for Stack Overflow.  This fairly interesting beginner question is up, but has already accumulated a couple of 'close' votes.  One of them is for 'off topic' but, possibly because I'm a theory guy, it seems very much on topic for programming and related topics.  You could argue for "computer science" potentially, but it would seem this, like questions on, oh, NP-complete problems and such, are things serious professional programmers should know and are interested in.  You could also make a case for mathematics and event the theory stack, although it's probably a little light for theory.  But with all of these separate categories, there seems to me to be a real risk that interesting questions will be modded/closed/moved until the OP loses interest.  Perhaps we've gotten a little too compartmentalized?

have already been created through .  have already completed their beta stage and are waiting for launch.  are in public beta stage.  are in commitment phase in   proposals are listed in   Now it is really confusing to find a suitable site to ask a question. As an example - I host a blog using . Now I have a question about this hosting. I want to post it in a . Where will I post? I have 2 options available now.     Are developers trying anything to solve this confusing matter?


I got confused about the usage of "yes" and "no".  I knew in English,"yes" or "no" should response to the meaning of sentence.   take a example. assuming a stuff is available.       is it available? -yes.      isn't it available? -yes.   but I not sure to  say "yes" or "no" when someone ask a complicated question with double-negatives.       is it unavailable?       isn't it unavailable?

I faced a problem to answer a negative question, for example, when someone asks you:      Don't you have any money?   It's a yes/no question but how should one answer the question without ambiguity?  When you answer "yes", does it mean "yes, I don't have any money"? or the other way "Yes, I do have money"? the questioner may think you are agreeing to the negative, that yes, you do not have any money.  I know it's better to answer with "on the contrary" but is it possible to answer yes or no?


$$\vdash (( p → q) →  p) →  p$$ how would I go about solving this with no premises. to get the implication i know i need $$(p → q) →  p$$ as my first assumption but im stuck to where to go from there

$$\big((P\rightarrow Q)\rightarrow P\big) \rightarrow P$$  I need to solve this using simple natural deduction rules  these can be hypothesis, $\rightarrow$ intro, $\rightarrow$ elim, conj and disjunct intro and elim, and negation intro (Reductio ad absurdum) and negation elimination (Double)


My high school chemistry textbook contained the following passage (the emphasis is mine):-     The correlation between the structure and properties helps in   discovering new materials such as high temperature superconductors,   biocompliant polymers for packaging, ...   I wanted to know what biocomplaint meant. So I googled it and Google displayed a 'did you mean bio-complaint' suggestion. Is there any difference between the biocompliant or bio-compliant?

Some compound words are written without hyphens (nonaggression, nonbeliever), some with hyphens (well-intentioned), and others with spaces (post office).  Is there a rule or good guide as to which option should be used?


I am trying to get access to my external hard drive and hopefully the data on it. However, my disk is not being recognized by the computer. I have tried opening Windows disk manager and it immediately gives me the pop-up window, that I have to Initialize the disk with ( MBR or GPT tables) if I want to use the disk, but when I click ok, it gives me the error: The request failed due to a fatal device hardware error, in disk part, it is being recognized but with the size of 0 bytes. I had used TestDisk program but the disk is not being recognized. Are there any other steps I can try for recovering data?

What steps can I take to try to recover lost or inaccessible data from any storage device?  Answers:   This applies to any computer storage device, e.g. internal/external hard drives, USB sticks, flash memory. The most important thing is to STOP using it, any type of I/O can ruin your chances of a recovery.     We have separate questions covering common problems with USB flash drives in greater detail:


I have a problem where by a section of my android app works fine on android version 4.1.2 but throws a NullPointerException when the same section is executed on android 4.4.3. My minimum sdk is set to 15 and target sdk is 21. Please find the code below:  try {     FileInputStream towe = new FileInputStream(path2);     re = new BufferedReader(new InputStreamReader(towe));     while ((res = re.readLine()) != null) {         result.append(res);     } } catch (FileNotFoundException e) {     e.printStackTrace(); } catch (IOException e) {     e.printStackTrace(); } finally {     try {         re.close();           //ERROR IS GENERATED AT THIS LINE     } catch (IOException e) {         e.printStackTrace();     } }   Morning guys, been away for a while. It turned out Exception was being thrown because of file path. I had hard-coded the path for android 4.1.2 but in 4.4.3 that path was different even though device was the same. I ended up using the   android.os.Environment.getExternalStorageDirectory();  method. Now working fine on both. Thanks for the suggestions

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?


How can I disable the hot corner /Activities corner using the Terminal?  I know I can use the Tweak Tool, as mentioned , but I am writing a little bash script to reconfigure my Ubuntu Gnome quickly to my needs so I would like to use e.g. gsettings for that.

GNOME shell has the so-called feature "hot corner", that opens the dashboard  if the mouse touches the top-left corner of a monitor screen.  I want this disabled I used to have a GNOME shell extension, yet the repository is not found anymore:  git clone git@github.com/Ahrak/gnome-shell-extension-disable-hot-corners.git fatal: repository 'git@github.com/Ahrak/gnome-shell-extension-disable-hot-corners.git' does not exist


I am currently doing some coursework for my exams, and part of my IT project is to record some audio, and assess it. I recorded this audio on my iPhone, and I plan on using Audacity to edit it. I am having a problem with getting the voice memos off my iPhone, and that's preventing me from doing my coursework. Does anyone know what to do? I use iTunes 11.1.3

iOS seems to refuse to allow me to email "long" voice memos, and I'm unaware of any way to extract them from iTunes backups of my phone. How can I retrieve entire voice memos that aren't really short?


It's time once again to support your favorite open source project through our Free Vote-Based Advertising for Open Source Projects. We are clearing the leaderboards to start the first half of 2013. Here is your chance to create a . Create a graphical ad for an open source programming project and post it as an answer to this question (in the right format), and it will feed live remnant ads on Stack Overflow. Ad Requirements It must be an advertisement soliciting the participation and contribution of programmers writing actual source code. This is not intended as a general purpose ad for consumer products which just happen to be open source. It's for finding programmers who will help contribute code or other programmery things (documentation, code review, bug fixes, etc.). Your ad should be an original creation which has not previously appeared on Stack Overflow. Please do not resubmit entries that have appeared as ads on Stack Overflow in previous periods. In order to work, the answers you post to this question must conform to the following rules. Answer Template  [![alternative text if image is not displayed][1]][2]        [1]: http://image-url   [2]: http://clickthrough-url   Please do not add anything else to the body of the post. If you want to add any commentary, keep it in the comments. Image requirements  The image that you create must be 220 pixels by 250 pixels Must be hosted through our standard image uploader (imgur) Must be GIF or PNG No animated GIFs Absolute limit on file size of 150 KB Must have a 1px border if (part of) the background is white  The output, which ultimately will be served in an ad slot on Stack Overflow, can be previewed by clicking through to this URL:  Score Threshold There is a minimum score threshold an answer must meet (currently 6) before it will be served up by that URL and shown on Stack Overflow. You can see all the ads that currently make the threshold and meet our criteria on this page:

It's yet again time once again to again yet support your favorite open source project through our Free Vote-Based Advertising for Open Source Projects. We are clearing the leaderboards to start the second half of 2013. Here is your chance to create a . Create a graphical ad for an open source programming project and post it as an answer to this question (in the right format), and it will feed live remnant ads on Stack Overflow. Ad Requirements It must be an advertisement soliciting the participation and contribution of programmers writing actual source code. This is not intended as a general purpose ad for consumer products which just happen to be open source. It's for finding programmers who will help contribute code or other programmery things (documentation, code review, bug fixes, etc.). Your ad should be an original creation which has not previously appeared on Stack Overflow. Please do not resubmit entries that have appeared as ads on Stack Overflow in previous periods. In order to work, the answers you post to this question must conform to the following rules. Answer Template  [![alternative text if image is not displayed][1]][2]        [1]: http://image-url   [2]: http://clickthrough-url   Please do not add anything else to the body of the post. If you want to add any commentary, keep it in the comments. Image requirements  The image that you create must be 220 pixels by 250 pixels Must be hosted through our standard image uploader (imgur) Must be GIF or PNG No animated GIFs Absolute limit on file size of 150 KB Must have a 1px border if (part of) the background is white  The output, which ultimately will be served in an ad slot on Stack Overflow, can be previewed by clicking through to this URL:  Score Threshold There is a minimum score threshold an answer must meet (currently 6) before it will be served up by that URL and shown on Stack Overflow. You can see all the ads that currently make the threshold and meet our criteria on this page:  Note: As with previous  of this program, if your ad has already appeared in a previous cycle, it is not eligible to be run in this cycle. However, if it did not make it through the previous cycle, it is eligible.


I am following Macdonald's Symmetric Functions and Hall Polynomials, and in his example-section. He stated the following without any proof, and I'm trying to understand how he reached the expression. Any assistance will be appreciated.   A partition $\lambda = (\lambda_1, \lambda_2, \cdots, \lambda_n)$ can be written in the Frobenius notation $(\alpha_1,\cdots,\alpha_r \ \vert \ \beta_1,\cdots,\beta_r)$, where $\alpha_i = \lambda_i - i$, $\beta_i = \lambda'_i - 1, \ $ $(1 \leq i \leq r)$. $r$ is the length of the intersection of the young diagram of $\lambda$ with the diagonal $i=j$.  Essentially, in the Young Diagram of $\lambda$, if we discard the diagonal, which contains $r$ squares, counting left to right to the right of the diagonal gives us $\alpha$, and counting downwards to the left of diagonal gives us $\beta$.  Macdonald states: $$\sum_{i=1}^{n}t^i\big(1-t^{-\lambda_i}\big)=\sum_{j=1}^{r}\big(t^{\beta_j + 1}-t^{-\alpha_j}\big)$$

Let $\lambda$ be a partition of length $n$ and suppose its largest diagonal block, the Durfee square of $\lambda$, has size $r$. By this I mean that $\lambda = (\lambda_1,\ldots,\lambda_n)$ is a non-increasing sequence of numbers, which I depict by the following diagram  \begin{align*} &\square \cdots \square \square \quad (\lambda_1 \text{ squares })\\ &\square  \cdots \square \quad (\lambda_2 \text{ squares }) \\ &\quad\vdots \\ &\square \quad(\lambda_n \text{ squares }) \end{align*}  and the largest $i\times i$ block one can fit to the topmost left is of size $r\times r$. The conjugate partition $\lambda'$ is given by reflecting the drawing above along the diagonal. If $\alpha_i$ and $\beta_i$ denote the sequence of numbers of blocks to the right of the diagonal in the $i$th row, and below the diagonal in the $i$th column, we write $\lambda = (\alpha_1,\ldots,\alpha_r\mid \beta_1,\ldots,\beta_r)$.   For example, for the partition $(5,4,2,1,1)$ has diagram $$ \begin{align} &\blacksquare\square\square\square\square\\ &\square\blacksquare\square\square\\ &\square\square\\ &\square\\ &\square \end{align} $$  and its conjugate is $(5,3,2,2,1)$. Its diagonal has length $2$, and in Frobenius notation we have $\lambda = (4,2\mid 4,1)$.  How can one show that the numbers $\lambda_1',\lambda_2'-1,\ldots,\lambda_r'-r+1,r+1-\lambda_{r+1},\ldots,n-\lambda_n$ form a permutation of $1,\ldots,n$? If $\lambda = (\alpha\mid \beta)$ in Frobenius notation, this is equivalent to the identity $$\sum_{i=1}^n t^i (1-t^{-\lambda_i}) = \sum_{j=1}^r (t^{\beta_j+1}-t^{-\alpha_j})$$ which is Example 4 in page 11 of MacDonald's Symmetric Functions and Hall Polynomials, which he states without proof, so presumably this is easy.   Continuing with the example, we compute that the sequence for $\lambda = (5,4,2,1,1)$ is $$5,3-1,3-2,4-1,5-1=5,2,1,3,4$$ a permutation of $1,2,3,4,5$.  In $(1.7)$ MacDonald proves that if we take $m\geqslant \lambda_1$ and $n\geqslant\lambda_1'$ then the numbers $$\lambda_i+n-i,1\leqslant i\leqslant n,\quad n-1+j-\lambda_j',1\leqslant j\leqslant m$$  are a permutation of $0,\ldots,m+n-1$ by labelling the vertical and horizontal edge-lines on the diagram of $\lambda$ fitted inside the diagram of $(m^n)$, but I haven't been able to come up with a proof similar to this.


In any finite group $G$, the number of elements not equal to their own inverse is an even number. I'm not sure how to go about this. I was considering assuming the number of elements not equal to their own inverse is an odd number (contradiction), but I'm not sure how to get a contradiction. I was considering thinking about when $|G|$ has even order and odd order, and then finding a way to do it directly, but I'm not sure. I think that in a finite group the number of elements equal to their own inverse should be even since they come in pairs. Any hints or solutions are greatly appreciated.

In any finite group, number of elements not equal to their own inverses is even number  In my book they have paired elements with their inverses, being elements and inverses different from each other. How do i see this hint ? Thanks


Let A,B be infinite sets. Denote |A|,|B| as the cardinality of A,B. I am struggling to prove that |A|+|B| = |A|*|B| = max(|A|,|B|)

Prove that if $a^2=a$ for each infinite cardinal $a$ then $b + c = bc$ for any two infinite cardinals $b,c$.   I tried $b+c=(b+c)^2=b^2+2bc+c^2=b+2bc+c$, but then I'm stuck there.


The Rune Priest in my group grants DR4 to anybody next to him. Not a problem. But then, my players heard me say: "He swings his axe against the paladin of Khalmyr and: 15 damage plus 8 cold damage."  That was all it took for the Rune Priest (who was feeling useless until the cleric stopped playing with us) to say: "Sooo... Does the DR I grant count twice? 'Cause it is 15 from the axe and 8 from the cold, right?"  And I seriously didn't know. If does make sense, though. Because if they had used a potion of resistance, it would only count against the extra damage.  So... What is the correct way?

Resist all applies to all damage types (including untyped damage), reducing the damage by the resist amount. What happens when a single attack deals two different kinds of damage? Not combined damage, like "1d6 fire and cold damage", but two separate kinds of damage, such as "1d6 fire damage plus 1d6 cold damage"? Consider the following example: A creature with the following power...  Rimehound Bite Melee 1 Attack: +X vs AC Hit: 1d12+6 damage plus 1d6 cold damage  ... attacks a player wearing , which grants "resist 1 all". Does the Rimefire Plate reduce the damage by 1, or by 2?


Edit: I researched also link suggested above - it is option (3) And indeed is very helpful. Especially @LuisAlvarado's answer - it contains table which suggest using linux-firmware-nonfree - I tried and it did not worked (possibly because my system was polluted by remnants of previous attempts). Instead, b43-fwcutter from option (2) after clean reinstall worked for me. Linked answer contains good explanation of the process, but advice about exact module to use might be incorrect. wileress.kernel.org has different value value, which worked for me.  Original post:  I cannot get bcm4318 working on Lubuntu 14.4.  This card worked on lubuntu 12.10 but upgrading failed, and after full reinstall from liveUSB I cannot get wifi to work. I tried these suggestions:   (1)  suggests to apt-get --reinstall install bcmwl-kernel-source (2)   says: apt-get purge bcmwl-kernel-sourceinstead, says: apt-get install b43-fwcutter firmware-b43-installer but did not work either. (3)  apt-get install linux-firmware-nonfree - well worth reading, excellent explanation of problem.   Every time I purged packages from previous try and rebooted afterwards.   (4)  . It seems that b43 from (2) should work (bcm43xx entry is blacklisted). But no luck. (5) Downgrading is also suggested by  but I was hoping there is something newer/better. The author claims that every release makes bcm43xx harder.   What else I should try?  I checked "ultimate authority" on bcm43xx wireless,  which says (in debian section) to use option (2), but no luck.   By "no luck" I mean that iwconfig says no wireless connection. In my office I have wired connection to modem but no apparent wireless. Is iwconfig a right way to test if my wireless is alive?  lsmod | grep -e b43 -e wl:  b43                   356470  0    bcma                   42043  1 b43   mac80211              545990  1 b43   cfg80211              409394  2 b43,mac80211   ssb                    51854  2 b43,b44     lspci -nn | grep 0280  06:02.0 Network controller [0280]: Broadcom Corporation BCM4318 [AirForce One 54g]   802.11g Wireless LAN Controller [14e4:4318] (rev 02)     uname -mr   3.13.0-24-generic i686     My laptop is Acer Aspire 5610Z with 0.5GB of RAM which I am going to upgrade to 4GB ASAP.    I got it working.  Correct answer is option (2), at least for my combinations of whatever is relevant.  What probably caused my earlier problems was that I was installing using synaptic gui. When I did install using terminal and apt-get, I noticed that apt-get update complained about duplicate sources. Once resolved, I again went over whole installing exercise, including fresh reinstall (to make sure there are no remnants of other installs), and straight to option (2) as suggested by wireless.kernel.org.   Regarding other options, it is above my paygrade to decide if they are invalid and need to be updated, or can stay as is, if approaches suggested by (1) and (3) are correct and may work for someone else.

I'm having serious problems installing the Broadcom drivers for Ubuntu. It worked perfectly on my previous version, but now, it is impossible.   What are the steps to install Broadcom wireless drivers for a BCM43xx card?  I'm a user with no advance knowledge in Linux, so I would need clear explanations on how to make, compile, etc.    lspci -vnn | grep Network showed:   Broadcom Corporation BCM4322 802.11a/b/g/n Wireless LAN Controller [14e4:432b]      iwconfig showed:  lo        no wireless extensions. eth0      no wireless extensions.   NOTE: Answer below is updated every time new information is added and confirmed working.


Is the use of the contracted negative form of Do, the DON'T, in reference to a singular event or action acceptable in formal writings as is in song lyrics composition?

I'd like to know how the sentence "That don't impress me much" sounds to a native English speaker.  The phrase is the title of a song by Shania Twain, and to my eyes it contains a clear error. It is obviously intended, and I want to know what was the effect that the author wanted to obtain.  Other examples that come to mind:   “She's got a ticket to ride, but she don't care” — The Beatles “My love don't cost a thing” — Jennifer Lopez “It don't matter” — Akon “She don't care about me” — heard in the Lost series “It Don't Mean a Thing” — a jazz album title “The Sun Don't Lie” — another album title


I just installed ubuntu 16.04.1 on my parents their old computer And if I want to connect to the internet, I get no connections to see  When I want to see if Broadcom Corporation is enabled it isn't in the list


We suppose all rings are commutative with unity.  I am looking for examples of a tensor product $B\otimes_A C$ which is not noetherian, where $A$ is a noetherian ring and $B, C$ are noetherian $A$-algebras.  The more examples the better. In other words, I'm asking a big list of examples.

Let $F$ be a field and $K$ and $L$ be extension fields of $F$ such that  $\mathrm{tr.deg}_F(K) = \infty$ and $\mathrm{tr.deg}_F(L) = \infty$.  It seems to be proved that $K\otimes_F L$ is not noetherian by the following paper.     P. Vámos, On the minimal prime ideals of a tensor product of two fields, Mathematical Proceedings of the Cambridge Philosophical Society, 84 (1978), pp. 25-35.   However, I don't have an easy access to a university library. I would appreciate if someone would post the proof (which needs not be that of Vámos).


Hi want to delete the snow leopard I have installed on my Hackintosh and replace with Ubuntu via USB as don't have access to cd drives. Please help!

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


Suppose $f$ is differentiable on $[0,\infty)$ and $\displaystyle \lim_{x \to \infty} \frac{f(x)}{x} = 0$. Show that $\displaystyle \liminf_{x \to \infty}|f'(x)| = 0$.   What I have tried is to apply the mean value theorem to $\frac{f(y)}{y} - \frac{f(x)}{x}$ with $0 < x < y$. There exists $c_x \in (x,y)$ such that $\dfrac{\frac{f(y)}{y} - \frac{f(x)}{x}}{y-x} = \frac{f'(c_x)}{c_x}- \frac{f(c_x)}{c_x^2}$. From here we get $$|f'(c_x)| \leq \frac{c_x}{y-x}\left|\frac{f(y)}{y} - \frac{f(x)}{x} \right| + \left|\frac{f(c_x)}{c_x} \right| $$  Now I want to set $y = 2x$ and take $\liminf$ of both sides to get $0$, but I am unclear on:   If $\liminf_{x \to \infty} |f'(c_x)| = 0$, then $\liminf_{x \to \infty} |f'(x)| = 0$. I think this is true? How to handle the factor $c_x/(y-x) = c_x/x$ when taking $\liminf$?

Let $f$ be a differentiable Function on $(0,\infty)$ such that $\lim_{x\to \infty}\frac {f(x)}{x}$=0.  I have to show that $\liminf_{x\to \infty}|f'(x)|=0$.  I had thought to apply the mean value theorem for the function $g(x)= \frac {f(x)}{x}$ over the interval $(x,2x)$ so that $$ \frac{\frac {f(2x)}{2x}-\frac {f(x)}{x}}{x}=g'(c)=\frac{cf'(c)-f(c)}{c^2} $$ for $c\in (x,2x)$. Then  $$ \frac {f(2x)-2f(x)}{2}=\frac{cf'(c)-f(c)}{c^2}=\frac {f'(c)}{c}-\frac {f(c)}{c^2} $$ How to proceed further I have no idea. Is my way is right? Or do I have to choose another way? Any help will be appreciated


I can't install tux-paint , tux-math , tux-typing ,k geography. please tall me how to install this app in ubuntu software?

How can I install applications like Google Chrome on Ubuntu?  Are there any commands to install an application?    Index of answers:


Got a 2019 iMac 27" with 4 RAM slots. I have 2 x 16Gb and 2 x 32Gb RAM modules. This is how they are installed right now. Is this the most optimal way to install them, or the sequence does not matter?

I have a mid-2011 iMac which came with 4GB RAM (2x2GB). I just bought 8 GB (2x4GB) and added it to get a total of 12GB. The current configuration is as follows:    Given that the RAM is a different size, do I have the optimal locations for the different RAM chips? At the moment what I did was to simply add the 2 new sticks of RAM in the two empty slots.


I have heard some debate about whether or not the Wuhan virus can be transmitted human-to-human, but this doesn't make sense to me.  Why wouldn't it be able to?  Are there diseases that can only be transmitted from animals, not humans?

A friend told me, during a 3 minute discussion, that viruses that are endemic in host $A$ and make repeated jumps to host $B$ but can't be transmitted between individuals of species $B$, may slowly adapt (through these repeated jumps) to be able to be transmitted between individuals of host $B$ and become epidemic.  I don't know much about epidemiology. I don't understand how a virus population that is endemic to host $A$ may adapt to host $B$ with repeated jumps while the viruses that jump to host $B$ are dead end because they cannot be transmitted further more. Or Are these viruses able to jump back to host $A$ to bring back their newly acquired adaptations to host $B$?  Also, I might misunderstand the meaning of "repeated host jumps transmission". I first thought it meant repeated jumps from a reservoir population in host $A$ to host $B$, but it is also possible that it describes the dynamic of a virus population that is adapted to jump from species to species and they actually gain this ability by keeping jumping and jumping. But then, how could a virus species get adapted to jump from species to species? I'm a bit confused…. Can you give me some hints about this process of cross-species transmission through repeated jumps?


I have two file manager apps on the phone  The system file manager Downloaded file manager  But they both show different internal storage free space. System file manager                      | 9.1GB  Downloaded file manager(Total Commander) | 8.4GB  I'm curious about which is correct and what the true free space is.  Android 9

I have critical low storage level and can't understand what takes much of it and how that's possible that the installed applications can use 7 GB? I only use a few social media clients without any games or soft like Photoshop. Also on the second screenshot it indicates that the apps are using just 1.13 GB and so I can't understand the situation. Also what is the "Other"?


Given  $x^3-y^3=xy+61$. Find all pairs (x,y) of positive integers which satisfies the given equation.  I tried solving this by following method-  $(x-y)(x^2+y^2+xy)-xy=61$  $(x-y)[(x-y)^2+3xy]-xy=61$  $(x-y)^3+3xy(x-y)-xy=61$  I don't know if doing this was in any means fruitful or not.   Remember $x>y$, only then a solution is possible.

I'm trying to solve the following equation:  $$x^3-y^3=xy+61$$  I got:  $$(x-y)(x^2+xy+y^2)=xy+61$$  But I can't go any further. I am looking for a solution in integers.  I need some hints to proceed, please!


I need more disk space at /tmp and /usr folders. How will achieve this?  An error appeared:   root@kali:/home/Downloads# ./netbeans-8.1-linux.sh Configuring the installer... Cannot create temporary directory /tmp/.nbi-5055107.tmp

Previously, I have installed Windows 7 on my 320 GB laptop with three partitions 173, 84 and 63 GB each. The 63 GB partition was where the Windows was installed. The rest were for file containers.  Now I changed my OS to Ubuntu 12.04 LTS. I installed Ubuntu by replacing the entire Windows 7 on the 63 GB partition. The rest of the partitions remain as an NTFS Windows partition and I can still access them both (the 173 and 84 GB partitions).  Now I want to change the two partitions of Windows into an Ubuntu format partitions plus most importantly, I want to extend the 63 GB partition to more than a 100 GB because at the moment I am running out of disk space. Whenever I try to install any application, especially using wine, it always complains for a shortage of disk space.  How do I do the extending activity before I entirely format my laptop again and lose all the important files on my partitions?


I tried to install Ubuntu 13.04 from a Live USB, and it said it was successfully installed, and after the reboot I got an error message that said:  error: attempt to read or write outside of disk "hd0" grub rescue   I am new to Ubuntu. Please help.

I have installed Ubuntu 12.10 in a Western Digital external hard drive (320GB). This is a complete installation, not a live USB.  When I plug it in my HP desktop I go to the BIOS settings and boot off the hard drive, everything work perfectly as it should. Now this works on every single computer and laptop in my house (all HP), except for ONE. My HP ProBook 4530s.  When I select to boot of the USB I get the message:  error: attempt to read or write outside of disk 'hd0'   Now, I have removed the hard drive from my laptop and the external drive is the ONLY drive plugged in. Below is a screenshot of the message on the screen. After the message I navigate to ls / (as shown below):    After here I try to acces other folders under ls /, for example, I try to go to ls /boot to get to the grub folder. Then I get the same message as before: as shown below:    grub rescue> ls /boot  error: attempt to read or write outside of disk 'hd0' grub rescue> _   The only folders I can access without getting the message again are /home, /run and /usr.   So how do I:   Boot Ubuntu from GRUB2 (this screen) manually Set to automatically boot Ubuntu If possible an explanation for this problem   Thanks!


I am Indian holding an Indian passport, travelling to Colombia for a business visit via Amsterdam and Paris. I am a resident of South Korea, having valid visas for Korea and Colombia. Do I need a transit visa for Amsterdam and Paris?  Amsterdam layover: 3 hours, and Paris 5 hours.

I found many related questions on this site but I am still not sure about the rules. How can I decide if I need a visa to transit? Schengen members as of May 2021 are as follows:  Austria Belgium Czech Republic Denmark (excluding Greenland and the Faroe Islands - but an open border with the Schengen Area is maintained) Estonia Finland France (excluding overseas departments and collectivities) Germany Greece Hungary Iceland Italy Latvia Liechtenstein Lithuania Luxembourg Malta Netherlands (excluding Aruba, Curaçao, Sint Maarten and the Caribbean Netherlands) Norway (excluding Svalbard) Poland Portugal Slovakia Slovenia Spain (except Ceuta and Melilla) Sweden Switzerland


I was reading an article by two Harvard Astrophysicists, which mentioned the following:  "We value gold for many reasons: its beauty, its usefulness as jewelry, and its rarity. Gold is rare on Earth in part because it's also rare in the universe. Unlike elements like carbon or iron, it cannot be created within a star. Instead, it must be born in a more cataclysmic event - like one that occurred last month known as a short gamma-ray burst (GRB). "  From this, it is clear that what they are saying is that gold cannot be formed on earth, let alone in stars, and further, that the only event it can be formed by is a "cataclysmic event" like a "gamma-ray burst". Moreover, why can gold only form in outer space and not on earth? How did they conclude this?  My questions are simple, and should occur to anyone who reads this and doesn't know the answer: First, how did they conclude that gold can only be formed in a cataclysmic event? No explanation or even a hint of an explanation is provided, it is just stated.  Second: Is this a special property of gold (and therefore may possibly account for the "superiority" of its properties to other metals) or does the same hold true for other metals, such as silver, copper, iron etc. Or perhaps these other metals are not like gold and are produced on earth? Or maybe it depends on their relative sophistication, so that silver can, unlike gold, can be formed both in cataclysmic-events as well as stars, while iron (say) can be formed even on earth?  (I should add that I only know basic "school" (non-calculus!) physics and so any errors in the above are due to my own lack of knowledge.)

In all the discussions about how the heavy elements in the universe are forged in the guts of stars and especially during a star's death, I usually hear that once the star begins fusing lighter atoms to produce iron (Fe) that's the end of the star's life and the whole system collapses onto itself; and based on how massive the star was initially, it has different outcome - like a white dwarf, a neutron star or a black hole. I have rarely heard a detailed explanation of how the elements heavier than iron are produced. I would appreciate a convincing explanation of this process.


I am coding in java since long, However I am confused in Exception Handling. I have to check the valid user.  One way is the if the user is not in db throw no user found exception and then catch the exception and then show the message to the client.  Another way is to check whether the user is in db with if condition and then respond back with message.. Instead of exception  which one is better and why? When to use If and when to catch an exception

I have exceptions created for every condition that my application does not expect.  UserNameNotValidException, PasswordNotCorrectException etc.  However I was told I should not create exceptions for those conditions. In my UML those ARE exceptions to the main flow, so why should it not be an exception?  Any guidance or best practices for creating exceptions?


Did Patrick Bateman really kill Paul Allen, or was it just in his imagination?

Towards the end of the movie, we see  in an apartment full of dead bodies. He ends up confessing what he's done to his lawyer. Later he goes back to the apartment, only to find the bodies are all gone. What happened to the bodies?


I want to create a keybinding Ctrl+Alt+Delete on my Ubuntu PC. It should open htop, but I want maximum priority for it. I use this command.  xterm -fullscreen -fa 'Monospace' -fs 13 -e htop   It works well, but when I add priority, it needs root permissions  $ nice -n -20 xterm -fullscreen -fa 'Monospace' -fs 13 -e htop nice: cannot set niceness: Permission denied   When I use sudo, it works, but it runs the whole command as root. How can I run only nice with sudo? It would be ideal if it didn't ask for a password.

I want to turn my system on automatically every day. So I use the below code in my Python script, but sudo asks me for a password every time:  os.system('sudo sh -c "echo date \'+%s\' -d \'+ \        24 hours\' > /sys/class/rtc/rtc0/wakealarm"')   How can I run this script without sudo asking for the password every time?


From the jQuery.ajax documentation for the type parameter:     The type of request to make ("POST" or "GET"), default is "GET". Note:   Other HTTP request methods, such as PUT and DELETE, can also be used   here, but they are not supported by all browsers.   What specifically are they referring to when they say that PUT is not supported by all browsers? That is, are there any specific or notable examples where this is the case?

I've seen a couple questions around here like , which mentions:     Unfortunately that same browser won't allow me to test HTTP PUT, DELETE, and to a certain degree even HTTP POST.   I've also heard that browsers support only GET and POST, from some other sources like:        However, a few quick tests in Firefox show that sending PUT and DELETE requests works as expected -- the XMLHttpRequest completes successfully, and the request shows up in the server logs with the right method. Is there some aspect to this I'm missing, such as cross-browser compatibility or non-obvious limitations?


Is there any way to list/report out which posts use a specific Gutenberg block in the post - almost like a 'search blocks' feature? I run a blog with about 1000 posts, and recently, one of the Gutenberg blocks plugins that I use has become incompatible with my theme, so I needed to disable it. I now have a large number of posts that I need to update and change any of the posts that used blocks supplied by the now-disabled plugin to use the more generic WP-supplied blocks. Does WP have a straightforward way to identify which posts have these blocks so I can avoid 'editing' every single post on my blog just to see if the invalid blocks are present? Thanks in advance. P.S. I'm new to SE, so if this is in the wrong area or doesnt belong here, just let me know.

I have a plugin installed that adds additional custom block types that can be used in the Gutenberg editor (the plugin is called Block Lab). Now I want to remove that plugin. For that, I have to remove all the used instances of those blocks. Is there a way to find all the occurrences of a used block type?


I am using a variation on the following Arduino project and it works, though I'm not quite sure how when it comes to the push button:    The schematic (from p22 of ):    The 5V voltage source runs through a 10K resistor, which is connected to pin 2 and the push button.  I believe that the circuit works like so: when the button is not pushed, it is  a series circuit, and current only flows through the wire leading to pin 2. (Notably, the default state for digital pin 2 in the Arduino sketch is HIGH, not LOW.) When the button is depressed however, the circuit becomes parallel. Somehow, the circuit's action is constituted by this. Even if I'm essentially right I'm missing some details, so fill me in here.

This problem is decades old but I do not see a direct answer to it on this site. I want the following:    This circuit just allows to check the state of the button from inside the micro-controller. Nothing fancy. My questions:   Is there anything better than this simple design? Is the value of 100 kilo ohms resistor adequate for our days CMOS devices, like dsPIC30FXXXX and not a high power application?


To the best of my knowledge, light will always travel at the speed of light. How then does it get reflected and change directions? Wouldn't it have to decelerate, come to a stop, and then accelerate in the opposite direction?   Or would the direction of motion be discontinuous when graphed as a function of time?

When a photon of light hits a mirror does the exact same photon of light bounce back or is it absorbed then one with the same properties emitted? If the same one is bounced back does it's velocity take all values on $[-c,c]$ or does it just jump from $c$ to $-c$ when it hits the mirror?  Or, is the phenomenon of a mirror better explained using a wave analogy? If so, what is this explanation?


I am generating HTML dynamically through javascript and have 2 glyphs enclosed within a table cell.  The pencil glyph responds correctly however my code for the delete does not and I am not sure why.  This is the rendered HTML      and here is my javascript code to tie the event up to the element.  $(document).ready(function(){   $('#delete-dp').click(function (event) {       alert('pressed');       //add the datapoint ID to the array to be serialised to JSON and then stored in a html hidden field       deletedDatapoints.push($(this).data('id'));   }); })

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


My SO and I are currently staying in France under the country's visa long séjour, essentially a 1-year visitor visa. If we return to Europe after leaving when the visa expires we would naturally be covered by the Schengen visa for 90 days, which also begins the 180-day period. How do the rules for these two visas interact? For example, if we applied for another long séjour to begin at the end of our 90-day Schengen visa, does the Schengen period reset 90 days within the long séjour period? Will the French authorities frown on having visa types overlap like this? Our goal is to travel for around 2.5 years in Europe and then return home. We're American and can prove means and lodging for the entire period.

I am an American citizen living in Poland for 6 months.  I arrived in Poland on February 1, 2016 without a Visa. The count toward my Schengen days began. I received my Work Visa for Poland on April 7, 2016.  The work visa expires on July 7th. I intend to stay in Poland until July 30, 2016 (which is 180 days after I entered on February 1)  My question is, do the days that I am on a Work Visa count toward my "90 days within a 180 day period" as a tourist?  And when my work visa expires on July 7th, will I be able to remain in Poland until July 30?  February 1 -> April 7 = 66 days July 7 -> July 30 = 23 days Total days as a tourist = 89 days


I read that like swimming and like to swim :     [...] While he likes to swim always means that he enjoys propelling himself through the water using his own body power, he likes swimming could also be used if he enjoys watching it as a spectator.   However, while liking and enjoying don't seem to be very different (the former meaning "" and the latter meaning ""), enjoy to swim is ungrammatical.   Therefore, I would like to know what the difference is between liking and enjoying in reference to the fact that, while like to swim is possible, **enjoy to swim* is not.  Thank you.

Why is it that we have to use the gerund form for the first example? I have been told that it is not grammatical to use the infinitive form.  For some verbs, it's okay:     I wanted to study English.   I had to study English.   I needed to study English.   I tried to study English.   I traveled to study English.   But, for some verbs, it's incorrect:     I ended up to study English.     Why is that the case?


I'm actually quite confused. Let's see...  I have eaten and drunk.  Or  I have eaten and have drunk.  I know the first one sounds... well, I think it sounds right, but...   Another one-  Azel is growing up and eating more.  Or  Azel is growing up and is eating more.  How do you know when to repeat the conjunction "and"?

What is a general rule for use of auxiliary verbs in sentence? Should we duplicate it or not? For instance,     It is available for every item and (is) used with . . .


Lockheed Martin reported breakthroughs on nuclear fusion technology for energy. Are these claims scientifically realistic?  The claims have been reported in the media:

Are the claims made about the   realistic? Can such a small fusion reactor really work?


I am getting endless ign and err while updating the apt-get, i even used proxychains by the command : proxychains apt-get update But still the ign and err are same. I want to install tor browser but this apt-get install tor doesnt work. Are they related ? I need the answer fast. I'm pissed off by searching it on net.

In my office i want to update and download through (wget) and here they are using proxy?  How can i do this by commandline?


Figure 1 is easier for identifying the difference. However, sometimes the practice of cutting y-axes is not recommended. Which one to report?

One common way to "lie with data" is to use a y-axis scale that makes it seem as if changes are more significant than they really are.  When I review scientific publications, or students' lab reports, I am often frustrated by this "data visualization sin" (which I believe the authors commit unintentionally, but still results in a misleading presentation.)  However, "always start the y-axis at zero" is not a hard-and-fast rule. For example, Edward Tufte  that in a time series, the baseline is not necessarily zero:     In general, in a time-series, use a baseline that shows the data not the zero point. If the zero point reasonably occurs in plotting the data, fine. But don't spend a lot of empty vertical space trying to reach down to the zero point at the cost of hiding what is going on in the data line itself. (The book, How to Lie With Statistics, is wrong on this point.)      For examples, all over the place, of absent zero points in time-series, take a look at any major scientific research publication. The scientists want to show their data, not zero.      The urge to contextualize the data is a good one, but context does not come from empty vertical space reaching down to zero, a number which does not even occur in a good many data sets. Instead, for context, show more data horizontally!   I want to point out misleading presentation in papers I review, but I don't want to be a zero-y-axis purist.  Are there any guidelines that address when to start the y-axis at zero, and when this is unnecessary and/or inappropriate? (Especially in the context of academic work.)


My program  #include <iostream>  using std::cout; using std::endl;  int main() {          int a[] = {1, 3, 5, 7, 9};          for (int i = 0; i < n; i++) {                 int address = &a[i];                 cout << "a[" << i << "] = " << a[i] << " at address " << &a[i] << " = decimal " << address << endl;         }  }   I want to print array element address in decimal, but above code fails to compile.  I have also tried to print it using   cout << std::dec << &a[i] << endl;   but that does not work too    Answer: Figured it out from    Have to cast the address to reinterpret_cast<std::uintptr_t>   cout << "a[" << i << "] = " << a[i] << " at address " << &a[i] << " = " << reinterpret_cast<std::uintptr_t>(&a[i]) << endl;

I am trying to adapt an existing code to a 64 bit machine. The main problem is that in one function, the previous coder uses a void* argument that is converted into suitable type in the function itself. A short example:  void function(MESSAGE_ID id, void* param) {     if(id == FOO) {         int real_param = (int)param;         // ...     } }   Of course, on a 64 bit machine, I get the error:  error: cast from 'void*' to 'int' loses precision   I would like to correct this so that it still works on a 32 bit machine and as cleanly as possible. Any idea ?


I was using Visual Studio for 2 years in Windows, but now I am using Ubuntu. Are there any other IDEs to use that are as high quality as Visual Studio? Please don't tell me the name of another IDE that tells me to download 5 GB of files before I can even test it, and then I'm supposed to try to run the whole thing with Wine. I want to use it in Ubuntu as an application for Linux, not install a Windows application in Ubuntu with Wine.

This question exists because it has historical significance, but it is not considered a good, on-topic question for this site, so please do not use it as evidence that you can ask similar questions here. See  for more information.   This is a community wiki for IDEs available on Ubuntu. Please post one IDE per answer (including more than just a screenshot or a link, please at least put a short description).  In your answer, tell us what the IDE is for (which language(s) or if it is RAD capable).


Recently I came across a small, but meaningful JavaScript question:   It was closed as a duplicate, and that makes sense as there's another highly upvoted question that covers it:   The problem is that 4 years and 9 months later, the top answer, selected answer, and even an answer that cover the modern functionality (from when it was a TC39 proposal) are out of date. There's a standard feature available in  that provides the requested functionality.  I'd like nothing more than to edit the answers with the ECMAScript 2020 way, point to polyfills for backwards compatibility, and move on. That's where I ran into a little issue because it seems quite a few others would like nothing more than to do the same, and the edit queue is full. My next thought is "Well, time to help out!", but I can't work the edit queue. Editing is incorrect, I accept my concept of "small change" was at odds with the community and a new answer would be the appropriate way, but my later question still stands.  Frankly I see this as a pretty major detriment to the usefulness of SO in context of an ecosystem that sees improvements and growth so quickly. There is no way that the comment closest to the modern best answer will amass an additional ~300 upvotes to make its way to the top with anything but a user powered campaign along the lines of "Down with the superceded answers!" where we gather a critical mass of users to start looking for these questions and break the rules by brigading them to bring the newer best practices up to the top.  In the specific context of this duplicate I'm extremely happy to see another user was able to get an answer in regardless of the flagging and closure.   My question in a nutshell: What can we do when we can't do what's best for improving SO questions and answers by following the rules because the rules and system are too overloaded and won't allow us to help?

I was thinking about this issue from time to time but I didn't know whether it really exists or just an speculation on my side until today when I woke up [!], I saw  downvoted (in the meantime I'll leave that answer unedited for the sake of discussion; note that this is just a sample. I'm not asking "how to deal with this specific answer." The question is completely general as it's nearly impossible to keep track of all of your answers to see whether they require updating or not). While the downvoter didn't explain a thing, I suspect the reason is that the answer is no longer applicable (It's one of the new features in iPhone OS 3.0). As we go to celebrate a long sequence of birthdays for Stack Overflow (hopefully!), we're going to see lots of answers become obsolete. How we're going to deal with this issue?


I've never seen any iron have an on/off button. So my guess is that most of them do not have one. Is there any specific reason for that?

The absolute majority of electrical appliances have an On/Off switch. However, the absolute majority of sandwich toasters do not - you just plug them into the socket and unplug them when you're done. At least, that's the case for all household sandwich toasters I've ever seen. I'm referring to this device, not the vertical toaster (where the lever doubles as a switch):    It looks like some models do have a switch, but apparently these are just the larger/industrial types, not the common variety.  Why is that?


Evaluate  $\int_{\frac{25\pi}{4}}^{\frac{53\pi}{4}}\frac{1}{\left(1+2^{\sin x}\right) \left(1+2^{\cos x}\right)}dx$  My Attempt:  I tried using the property that $\int_{a}^{b}f\left(a+b-x\right)dx=\int_{a}^{b}f(x)dx$ and properties of periodic functions but ended up with a mess. The answer is $\frac{7\pi}{4}$


I think I've to show it's path connected, but can't figure out the path functions explicitly. Can anyone give these path maps?

Well, I am not getting any hint how to show $GL_n(\mathbb{C})$ is path connected. So far I have thought that let $A$ be any invertible complex matrix and $I$ be the idenity matrix, I was trying to show a path from $A$ to $I$ then define $f(t)=At+(1-t)I$  for $t\in[0,1]$ which is possible continous except where the $\operatorname{det}{f(t)}=0$ i.e. which has $n$ roots and I can choose a path in $\mathbb{C}\setminus\{t_1,\dots,t_n\}$ where $t_1,\dots,t_n$ are roots of $\operatorname{det}{f(t)}=0$, is my thinking was correct? Could anyone tell me the solution?


I have divided my tex files as follows:  . ├── content │   ├── abstract.tex │   ├── mainA │   │   └── a.tex │   ├── mainB.tex │   ├── mainC.tex │   └── MainD │       ├── d.tex │       └── dd.tex ├── main.tex   In my main.tex file, I include all these files.   My  \tableofcontents just outputs one line with title. What am I missing? Below is my MWP.  \documentclass[runningheads]{llncs}  \begin{document} \title{How fancy can the title be}  \maketitle \tableofcontents  \input{content/mainA/a.tex} \input{content/mainB.tex} \input{content/mainC.tex} \input{content/mainD/d.tex} \input{content/mainD/dd.tex}   \bibliography{references}}  \end{document}

I can't get the TOC to work. I remember it worked before, but there was something I did (unfortunately I can't remember what it was), and after that the TOC just stopped working.  Here is a part from my document:  \documentclass[deutsch]{llncs}  \usepackage{graphicx} \usepackage[labelformat=empty]{caption} \usepackage{subcaption} \captionsetup{compatibility=false}  \bibliographystyle{unsrt}  \pagestyle{headings} \begin{document}  \sffamily  \begin{titlepage}     %Some stuff here \end{titlepage}  \thispagestyle{headings} \tableofcontents \newpage %more stuff here blablabla \section{test} \subsection{test2} \end{document}


I get this message each time I submit an improvement.    This has been happening since yesterday. Also, the next Suggested edit always fails to load afterwards.  I'm on a 3G network, so maybe a flaky connection? I also use Firefox 25 (haven't checked with anything else).

On approving an edit, I just get this pop up since morning. At first I thought there might be some internet connection issue, but this is now the 3rd to 4th time I got the same error; also, the review is accepted because on refresh I can see my name with approved text beside, but it still throws this error.    I am on a Windows 7 machine, running Firefox 24 (Icognito/Private Mode)    Also, this happens only when edit(1) is written on an question/answer, I don't go to review queue and approve, these reviews were directly loaded from the notification beneath the question/answer.  Martijn Pieters reproduced the problem from the review queue three times; each time the improve option was picked, accepting the suggested edit but editing the post some more. The network console shows that posting to https://stackoverflow.com/review/task-reviewed fails, the server responds with a 404 error:  Request headers: POST /review/task-reviewed HTTP/1.1 Host: stackoverflow.com Connection: keep-alive Content-Length: 137 Accept: application/json, text/javascript, */*; q=0.01 Origin: http://stackoverflow.com X-Requested-With: XMLHttpRequest User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_7_5) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/31.0.1650.63 Safari/537.36 Content-Type: application/x-www-form-urlencoded DNT: 1 Referer: https://stackoverflow.com/review/suggested-edits/3575396 Accept-Encoding: gzip,deflate,sdch Accept-Language: en,en-US;q=0.8,nl;q=0.6,nb;q=0.4,no;q=0.2,de;q=0.2,fr;q=0.2 Cookie: <redacted>  POST data: taskTypeId=1&reviewTaskId=3575396&taskResultTypeId=5&fkey=f8791a329b445b658876f4d3afe7961e&postCommentId=null&taskResultSubtypeFlags=null  Response headers: HTTP/1.1 404 Not Found Cache-Control: private Pragma: no-cache Content-Type: application/json X-Frame-Options: SAMEORIGIN Date: Fri, 13 Dec 2013 12:04:53 GMT Content-Length: 0   On the  itself, no record is made of the accept; instead the suggested edit is recorded as approved by 3 people not including Martijn Pieters. In this case the improve review arrived too late.  In , improve again resulted in the error, but the Community account is shown rejecting the edit.


I deleted "quiet splash" from GRUB_CMDLINE_LINUX_DEFAULT in the GRUB config file.  And when I reboot with the command line, I can see the commands until it reaches target reached restarting now  And then.... nothing, it freezes there. So it is not possible to shut down.  It is a dual boot of Win10 with Ubuntu 16.04  I had a similar problem on launch but I fixed it on adding acpi=off after pushing the E key in the GRUB menu.  EDIT  I changed acpi=off to acpi=noirq and this gave me a freeze on restart and when I did force shutdown and restart it gave me a purple screen with nothing. I had to edit again from the GRUB menu to put it back to acpi=off    What else can I try?

I've installed Xubuntu 15.04 on a Lenovo IdeaCentre A740 QHD with a Haswell CPU (BIOS revision 00KT19AUS) and NVIDIA GeForce GTX 850A 2GB. It's mostly working, except when I do a shutdown or reboot, it doesn't actually turn off the power after quitting everything:    So I have to click the power button to actually turn it off.    I've kept the Windows 8.1 installation in case there's any future firmware. Before installing Xubuntu, I turned off Fastboot from Windows, then installed Xubuntu. Unfortunately, the UEFI BIOS didn't let me change boot order so that Ubuntu actually started as default. I tried bcdedit /set {bootmgr} path \EFI\ubuntu\shimx64.efi, tried turning off "quickboot" (whatever that is) in BIOS, tried the Boot-Repair program from a Live Session, and tried turning off SecureBoot, but still it would just boot Windows. I ended up, with the help of EricC^^ of #ubuntu on freenode, just switching around the .efi files to trick the boot manager into thinking Ubuntu was Windows:  cp /boot/efi/efi/boot/bootx64.efi{,.backup} cp /boot/efi/efi/microsoft/boot/bootmgfw.efi{,.backup} cp /boot/efi/efi/ubuntu/grubx64.efi /boot/efi/efi/boot/bootx64.efi cp /boot/efi/efi/ubuntu/grubx64.efi /boot/efi/efi/microsoft/boot/bootmgfw.efi cp /boot/efi/efi/ubuntu/grubx64.efi /boot/efi/efi/microsoft/boot/grubx64.efi sudo vim /usr/lib/os-probes/mounted/efi/20microsoft # and changed bootmgfw.efi to bootmgfw.efi.backup update-grub   I don't know if any of this has a bearing on the shutdown trouble.  EDIT: Come to think of it, the reboot from the Xubuntu installation (when I was booted through a USB drive) didn't work either.    What I've tried so far to get it to shut down:   acpi=off → no difference acpi=force → no difference install proprietary Nvidia drivers → that just made X not start with the message "bbswitch: No discrete VGA device found" various variations on sudo poweroff, sudo shutdown now, sudo shutdown -h now etc.     Also, if I reboot instead of shutdown, I get this psychedelic lightshow on my monitor and have to long-click the power button to turn it off:    If it's helpful, here's a  and perhaps even better: .    Also, perhaps related, I notice now that pressing the power button while logged in to XFCE turns the computer right off, even though I have XFCE power settings to "Ask when power button pressed" and "Do nothing" on any other buttons.  My /etc/systemd/logind.conf has no uncommented lines apart from the [Login] header.   There is a /usr/sbin/acpid process running as root.    EDIT: More revelations: Ctrl+Alt+Delete actually reboot fine from GRUB.  EDIT2: I've filed a  since this doesn't seem fixable with the regular tricks.  EDIT3: Solved with acpi=noirq and kernel 4.4 and newer.


I want to build a simple transceiver (half duplex) for 433.92 MHz ASK modulation. I have found a transmitter chip and a receiver chip that I want to use. I want to use the same antenna for RX and TX but I am unsure of how to approach this (The receiver can handle the full output power of the transmitter). I do not want to buy a ready-made circuit for this, I'm doing this mostly to learn.   The antenna is 50 ohms but the receiver and transmitter both have their own impedances and need some matching network. If I used separate antennas this would be simple (say a PI attenuator).   But I’m unsure of how this would work with having both RX and TX on the same antenna. My very naïve approach to this would be to use a splitter/combiner after the matching networks and accept the -3 dB loss from this. This way every side sees 50 ohms.  But this feels very wrong and any input here would be much appreciated!

Considering that the SDR board has one TX/RX output/input and one RX input, I am wondering how could I use one antenna for a half duplex communications on the same frequency.  The idea is to use the TX/RX output for transmitting and the RX input for receiving. The problem is that the required output power is around 47dBm (which is achieved after a HPA) and if I use a fairly good circulator (for joining Rx with TX) as  one, it gives a 20dB isolation and that is not enough as it would burn the whole thing with the reflected power (max. input power of the SDR is -15dBm after the LNA!). Scheme:     As an alternative, I have thought of using a electronically controllable switch that could open one path while closing the other. The problem with this option is that so far I have only found very expensive solutions and my budget is limited.  Can anyone give me some guides on building a PC controllable switch for this purpose (should withstand around 50W of power while offering the typical 50\Ohms of impedance)?  Otherwise, any different ideas/approaches on how could I solve the problem?


Suddenly, the design of the /users page changed like this:    Other pages, such as /questions or /tags, haven't changed at all, which makes me think this might have been a premature or accidental change.  Was this change purposeful or not? Is it part of a network-wide design changing process?  Please note that this is most probably unrelated to , as the screenshot is from . Also,  looks like a dupe at first, but this question focuses on reasoning, not a specific issue.

I don't remember seeing these buttons before... I'm pretty sure the "Users" page used to look like the other tabs with the options being in a row with red underlines to highlight which tab is active on the page.  Now there are buttons but for some reason, the "reputation", "new users", and "moderators" all hover highlight in dark blue, making the text difficult to read while "voters" and "editors" don't.    I'm guessing this is a fragment of the responsive design, as it does resemble the user pages on Stack Overflow. It's worth noting that this seems to have been rolled out to every site that I've checked, not only Meta Stack Exchange but the odd hover color only appears here (as far as I can tell).    So, I did some more poking around this morning and I realized that the reason that "reputation", "new users" and "moderators" have a different hover highlighting is because they're visited. Not quite sure how I missed this but it might help in determining how to fix it.  This is global across all sites with the buttons. Here's the page on M&TV:    As you can see, I've tested this by clicking on the "editors" and "moderators" tabs, which have dark circles around them after being "visited" but the other three do not because I haven't clicked on them. "Editors" is darker grey because it's the tab that's currently active.


So, I got a discussion tag badge some time ago. When I visited my activity page to check it, I saw something which I think as a bug.     The options in the activity page i.e Summary, questions, answers etc., are covering "Track the next one" button. When we hover on the options, these options take the color of the background.   .   This disappears when we click on "Track the next one". It changes to normal.

When I visit  I see this:     The "Congratulations! You've earned (badge)" section has dropped down completely beneath the tabs under it. The "You've earned a new privilege!" section has a gap at the bottom:     Shog9 says in comments how to reproduce this:     Gotta have earned a badge, not dismissed the notification, and be looking at your own profile.


Question: Prior to a meeting of 20 people, a file was prepared for each person with their names written. The person who comes first to the meeting picks a random file without looking at the names. Those who came later look for their own file. If their files were not taken by someone else, then they pick their own file. Else, they pick a random file. What is the probability of the last person in the meeting getting his or her own file?  It seems a bit tricky. I tried to solve directly by using conditional probability but failed since the cases are confusing.

This is a neat little problem that I was discussing today with my lab group out at lunch. Not particularly difficult but interesting implications nonetheless  Imagine there are a 100 people in line to board a plane that seats 100. The first person in line realizes he lost his boarding pass so when he boards he decides to take a random seat instead. Every person that boards the plane after him will either take their "proper" seat, or if that seat is taken, a random seat instead.  Question: What is the probability that the last person that boards will end up in his/her proper seat.  Moreover, and this is the part I'm still pondering about. Can you think of a physical system that would follow this combinatorial statistics? Maybe a spin wave function in a crystal etc...