I keep getting this error:   java.lang.OutOfMemoryError: Java heap space   Is there a way to fix this, I never had this problem running the same thing on Ubuntu but once I got Lubuntu this keeps occurring. Appreciate any help!

I need to increase the default java heap size to get OpenNMS Linkd service running smoothly, and fortunately I have 4/5 of my total installed memory free at any given time even when their is maximum load on the server. still java is not performing to it's bast. hence I need to increase the default java heap size.  Can anyone tell me how to do it?  I'm using Ubuntu 12.04 lts & total memory installed is 16 GB out of which generally 2GB to 4GB is used.  I have already checked below questions and they did not help me resolve my issue.        Please feel free to edit or comment for any additional details required.


I want a overflow-safe function that round a double like std::round in addition it can handle the number of significant decimal digts.  f.e.  round(-17.747, 2) -> -17.75 round(-9.97729, 2) -> -9.98 round(-5.62448, 2) -> -5.62 round(std::numeric_limits<double>::max(), 10) ...   My first attempt was  double round(double value, int precision) {     double factor=pow(10.0, precision);     return floor(value*factor+0.5)/factor; }   but this can easily overflow.  Assuming IEEE, it is possible to decrease the possibility of overflows, like this.  double round(double value, int precision) {     // assuming IEEE 754 with 64 bit representation     // the number of significant digits varies between 15 and 17      precision=std::min(17, precision);     double factor=pow(10.0, precision);     return floor(value*factor+0.5)/factor; }   But this still can overflow.  Even this performance disaster does not work.  double round(double value, int precision) {     std::stringstream ss;     ss << std::setprecision(precision) << value;     std::string::size_type sz;     return std::stod(ss.str(), &sz); } round(std::numeric_limits<double>::max(), 2.0) // throws std::out_of_range   Note:    I'm aware of setprecision, but i need rounding not only for displaying purpose. So that is not a solution. Unlike this post here  , my question is especially on overflow safety and in C++ (the anwser in the topic above are Java-specific or do not handle overflows)

What I would like is a method to convert a double to a string which rounds using the half-up method - i.e. if the decimal to be rounded is 5, it always rounds up to the next number. This is the standard method of rounding most people expect in most situations.  I also would like only significant digits to be displayed - i.e. there should not be any trailing zeroes.  I know one method of doing this is to use the String.format method:  String.format("%.5g%n", 0.912385);   returns:  0.91239   which is great, however it always displays numbers with 5 decimal places even if they are not significant:   String.format("%.5g%n", 0.912300);   returns:  0.91230   Another method is to use the DecimalFormatter:  DecimalFormat df = new DecimalFormat("#.#####"); df.format(0.912385);   returns:  0.91238   However as you can see this uses half-even rounding. That is it will round down if the previous digit is even. What I'd like is this:  0.912385 -> 0.91239 0.912300 -> 0.9123   What is the best way to achieve this in Java?


I need to prove that $$ 2^n > n^3\quad \forall n\in \mathbb N, \;n>9.$$  Now that is actually very easy if we prove it for real numbers using calculus. But I need a proof that uses mathematical induction.   I tried the problem for a long time, but got stuck at one step - I have to prove that:     $$ k^3 > 3k^2 + 3k + 1 $$   Hints???

Problem  For what natural numbers is $n^3 < 2^n$?  Attempt @ Solution   For $n=1$, $1 < 2$ Suppose $n^3 < 2^n$ for some $n = k \ge 1$ It looks like the inequality is true for $n = 0$, $n = 1$ and $n\ge10$ But, how can I prove this through induction?


When I entered following command in my terminal  ls -la /etc | grep "\->"   I got following list & need to know what type of link is this type    and kindly guide me how can I create this type of links.  the type of link is different  and i followed following instruction   created a folder called folder-a entered following command ln -sv folder-a folder-b and output is displayed as ‘folder-b’ -> ‘folder-a’  when i type ls - l the color is cyan blue folder-b -> folder-a   but i am expecting above image result

I'm confused with how symbolic links work. I hope someone can guide me in the right direction.  I want to put a demo online from our software, which normally only runs locally on a Mac Mini. So I put all the files in the var/www from my Ubuntu 12.04 server installation.  There are a lot of hardcoded links in the software which point to /Applications/XAMPP/xamppfiles/htdocs/narrowcasting  Of course, I could change all these code on my html/php files in /var/www, but that would be quite annoying. I hope I can fix this by creating a symbolic link. For example, I have a directory called thumb in /var/www/thumb. The PHP code is trying to put an image in /Applications/XAMPP/xamppfiles/htdocs/narrowcasting/thumb.   Can anyone give me a tip how to achieve this with a symbolic link?


I came across this result randomly and am quite sure it's right. Is there any way to prove it rigorously? The numerator always seems to be one less than the denominator. Thanks!

Can someone give an explanation using the definition of convergence in partial sum to show how the above infinite sum converges to 1?  Thanks


let $G$ a finite group, not abelian. I don't know if a short proof of this fact exists :   $$\mathbb{P}(xy = yx) \leq 5/8$$ $x,y$ are randomly picked.  Edit : If possible, i want to know if there is a shorter proof than this one :   (in french sorry)

Suppose that $G$ is a finite group. If $P( ab=ba ) >5/8$, prove $G$ is abelian.


I'm having problems with graphics that get "stuck" in Windows 7, usually when selecting an item in a menu. See screenshot.  It's removed if I change the resoultion of the screen.   How can I fix this?

Periodically when I select a menu command, the label or selected option gets "stuck" on screen and won't go away. I can close all open applications, including whichever one I was using when it got stuck, but it still won't go away.   In the screenshot below, I opened an new instance of IE just to show how the label stays on top. The label was not created by this instance of IE.    (I added the circle in MS Paint. That part isn't stuck.)  The label that gets stuck is the first menu command I select in IE. If a label is already stuck, a new one does not get stuck (regardless of which instance(s) of IE are involved). Based on this knowledge, I now just open IE on my secondary monitor, carefully open the context menu so the Properties command is in the bottom corner, and click it. This is not a solution.  The floating label never moves and is transparent to mouse input (if I click it, it's as if I clicked the item behind it).  The label does not go away if I close all running applications. I haven't tried stopping services or closing system tray items like Live Mesh.  The label does go away if I change the screen resolution and then change it back.  Any ideas how I can stop this from happening? It's happened a half dozen times and it's becoming quite disrupting to my work.


When downloading Ubuntu(Desktop version), for example Ubuntu 16.10 (Yakkety Yak) Netboot. After choosing arhitecture for example (i386) download directory opens and there is list of files:  Index of /ubuntu/dists/yakkety-updates/main/installer-i386/current/images/netboot  boot.img.gz ldlinux.c32 mini.iso netboot.tar.gz pxelinux.0 pxelinux.cfg/ ubuntu-installer/ xen/  Where can I find explanation what is the meaning of those files ad which one is correct for me ?

I want to burn Ubuntu Minimal CD ISO to an old, 1 GB USB thumbdrive. Regular ISO doesn't fit. I already tried Startup Disk Creator and Unetbootin but both failed. I tried installing GRUB and pointing it to boot like this:  insmod part_msdos linux /linux initrd /initrd.gz   but it doesn't work. I also tried dd but I ended up with not bootable drive.  Rufus worked on Windows with the same thumbdrive but I no longer use Windows.  What else can I do?


let $a,b,c>0$ and such $ab+bc+ca=3$,show that $$\dfrac{a}{a^3+b^2+1}+\dfrac{b}{b^3+c^2+1}+\dfrac{c}{c^3+a^2+1}\le 1$$  I want use Cauchy-Schwarz inequality $$(a^3+b^2+1)(\frac{1}{a}+1+c^2)\ge (a+b+c)^2$$ so $$\sum_{cyc}\dfrac{a}{a^3+b^2+1}\le\sum_{cyc}\dfrac{1+a+ac^2}{(a+b+c)^2}$$ it must to prove $$(a+b+c)^2\ge \sum_{cyc}(1+a+ac^2)=3+(a+b+c)+ac^2+ba^2+cb^2$$ then I can't do it.

let $x,y,z>0$ and such $xy+yz+zx=3$,show that $$\dfrac{x}{x^3+y^2+1}+\dfrac{y}{y^3+z^2+1}+\dfrac{z}{z^3+x^2+1}\le 1$$  To prove this inequality,I want use following Cauchy-Schwarz inequality $$(x^3+y^2+1)(\frac{1}{x}+1+z^2)\ge (x+y+z)^2$$ $$\dfrac{x}{x^3+y^2+1}\le \dfrac{1+x+xz^2}{(x+y+z)^2}$$ we have $$\sum\dfrac{x}{x^3+y^2+1}\le\dfrac{3+x+y+z+xz^2+yx^2+zy^2}{(x+y+z)^2}$$ it suffices to prove that  $$x+y+z+xz^2+yx^2+zy^2\le x^2+y^2+z^2+3$$


I'm using Ubuntu 14.04.01 Since Aug,14 in my laptop; everything has been running fine but this month Jan,15 there is update available called "Ubuntu Base" - after updating that I got this Error Message, Please let me know how to fix this.  The message error is below:  E:Encountered a section with no Package: header,  E:Problem with MergeList /var/lib/apt/lists/in.archive.ubuntu.com_ubuntu_dists_trusty_multiverse_i18n_Translation-en%%5fUS, E:The package lists or status file could not be parsed or opened.   After this error there is no way I can update the system - please help me how I can get rid of this message.

The computer gave me this output in a window:  E: Encountered a section with no Package: header E: Problem with MergeList /var/lib/apt/lists/archive.ubuntu.com_ubuntu_dists_natty_main_binary-i386_Packages E: The package lists or status file could not be parsed or opened.   How can I fix this?


If $E$ is a field, $F/E$ is a field extension, let $A$ and $B$ be two matrices with entries in $E$ then $A$ is similar to $B$ in $E$ if only if $A$ is similar to $B$ in $F$. I think it's true, but I don't know how to prove it. Any suggestion? Thanks.

Given a field $F$ and a subfield $K$ of $F$. Let $A$, $B$ be $n\times n$ matrices such that all the entries of $A$ and $B$ are in $K$. Is it true that if $A$ is similar to $B$ in $F^{n\times n}$ then they are similar in $K^{n\times n}$?   Any help ... thanks!


I have a logo_png class,  and if I use a text, it will works fine.  but if I use a image of the class, it will goes wrong:    you see the logo img is on top of the background image.  I want the image is like first snapshot, overlap the background image.    this is the code, the annotation is the logo.

口耳教育

   the class code:  .logo_png {     position: absolute;     z-index: 9999; }   the background image code is bellow:

       .....   its code is like this:  nav.navbar.navbar-default {     background: transparent;     border: none;     top: 48px;     position: absolute;     z-index: 9999;     right: 98px; }

I want to overlay one image with another using CSS. An example of this is the first image (the background if you like) will be a thumbnail link of a product, with the link opening a lightbox / popup showing a larger version of the image.   On top of this linked image I would like an image of a magnifying glass, to show people that the image can be clicked to enlarge it (apparently this isn't obvious without the magnifying glass).


Miracles are rare beneficial events that appear to have a supernatural intervention.  So might not the antonym in one word be tragedy? Of the dozens of other words suggested, tragedy for me expresses the most cataclysmic nature of the event:  NOT apocalypse, catastrophe, cataclysm, disaster, debacle or freak incident, though the last probably best describes tragedy as an antonym to miracle.

Are there any English words that mean "an unlikely calamity" in that same way that "miracle" can mean "an unlikely beneficial event"?  My thesaurus only provides antonyms of "miracle" that mean "a mundane event" rather than "a horrible event".  I'm thinking specifically of multiple unlikely failures occurring simultaneously: I suffer an unlikely injury that leaves me unable to leave the house and my usually-reliable telephone service suddenly cuts out for the day, so I can't phone for help.  Words like "catastrophe" and "calamity" seem too general, since I'd like to express the exceptional unlikelihood of the event (or events). The best I have is a descriptive phrase like "disastrous coincidence," but I'd prefer a single word.  Overtones of the divine or demonic are not required, but preferred.


I like to display php array in javascript, but in specific  element with id. below is my code which shows what I want to do.  <?php function ogolne_informacje(){      global $mypod;?>         <?php echo 'Pokój: '?><?php echo $mypod->display('room')."
";?>         <?php echo 'Email: '?><a href="mailto:<?php echo $mypod->display('user_email') ?>"><?php echo $mypod->display('user_email')."
";?>         <?php echo 'Telefon: '?><?php echo $mypod->display('phone')."
"; }?>    <?php $i =0; while ( $mypod->fetch() ) :{     ob_start();      ogolne_informacje();     $output[$i] = ob_get_clean();     $i++; } endwhile;?>

    How can I do that? Thanks!

What is the easiest way to encode a PHP string for output to a JavaScript variable?  I have a PHP string which includes quotes and newlines.  I need the contents of this string to be put into a JavaScript variable.  Normally, I would just construct my JavaScript in a PHP file, à la:  <script>   var myvar = "<?php echo $myVarValue;?>"; </script>   However, this doesn't work when $myVarValue contains quotes or newlines.


I am IT Graduate with good knowledge on SQL and C. I have done most of the SQL programming on Microsoft SQL Server in my academics. But i want to become Oracle DBA. Could you please suggest me a structural way to to start learning.  And also please suggest me what background work is needed before digging into it. Thanks

This question only needs one answer: a list of great resources for getting started with Oracle, including Database Administration, PL/SQL and SQL.   You may find your question has been closed as a duplicate of this one, if so, please don't be offended: we are trying to be as helpful as we can without . Closing a question as a duplicate of this one is us saying "What you really need is to spend some time reading some of the best resources available rather than have your specific question answered right now. If you do get through these resources, you'll soon be back with more !


I am a novice, so need simple instructions. I downloaded Ubuntu online to see if it could replace my current Windows XP, but when restarted, Windows XP starts, not Ubuntu.    How do I use Ubuntu, and how do I get this to use and English keyboard?

I currently have Windows 7 on my computer and I want to install Ubuntu alongside Windows safely.  Could someone please provide clear instructions?


I'm trying to make something very similar to this example:      I basically am trying to create various versions of fabric in Illustrator to show the layering process of fabrics in clothing. Any idea on how to achieve this? I'm looking into 3D Extrude and Bevel but I can't quite seem to get the natural curve.

I am working on an illustration for a client who needs it to be very photorealistic. I used illustrator to get as close to his expectation as possible but its not quite there yet.  Can anyone help me with any notes or recommendations on software and/or tools to use to achieve this?  Any help would be greatly appreciated.  This is what I came up with:   This is what the client needs it to be like:


I have a lookup on Veeva events object for delivery engagement with API name BH_US_Delivery_Engagement__c. When I am trying to access it on my code getting the above error. Can anyone help ? Also, PFA the screenshot.

I have an apex trigger that involves querying multiple objects. But I encounter this kind of error :      Error: Compile Error: A non foreign key field cannot be referenced in   a path expression: ObjectBs__r   Here's a portion of the trigger where I encounter such error message:   Set<Id> objAid = new Set<Id>();  Set<Id> objDid = new Set<Id>();  for(ObjectC__c c : Trigger.new) {         objAid.add(c.ObjectA__c);    }  List<ObjectA__c> objAList = [SELECT Id, Name, (SELECT Id, Name, ObjectD__c FROM ObjectBs__r) FROM ObjectA__c WHERE Id IN: objAid];  for(ObjectA__c a : objAList[0].ObjectBs__r) {         objDid.add(a.ObjectBs__r.ObjectD__c); }


I'm having an issue with this simple counter program:  import time counter = 0  def countup():   while counter < 10:       counter += 1       print counter       time.sleep (1);   countdown();  def countdown():   while counter > 0:       counter -= 1       print counter       time.sleep (1);   countup();  countup();   And the error I am getting is:      UnboundLocalError: local variable 'counter' referenced before   assignment   Does this mean that I need to define a counter variable inside each function? I have tried this, but it didn't work. I also tried a global variable at the start using: global counter = 0 but that didn't work either.  Apologies foor the noob question, I'm just a guy prodding a bit of python code.

How can I create or use a global variable in a function?  If I create a global variable in one function, how can I use that global variable in another function? Do I need to store the global variable in a local variable of the function which needs its access?


Currently i have a formula field on case object, which will return the no. of days the case is not touched. Here, i wanted to exclude the weekend days and the public holiday (which are already created in the company information).  Here is my current logic. Any suggestion is appreciated.  IF( IsClosed , null,  IF(ISNULL(PostDate__c),FLOOR(NOW() -  CreatedDate), DATETIMEVALUE(TODAY()) - DATETIMEVALUE(PostDate__c))).   Thanks

Our business has a requirement to calculate a due date on a case by using the created date and adding business hours, or business days. When we calculate business days it converts the days to 24 hours and divides the result by the business hours(10 hours) which is giving us wrong due dates.   Example:  If our created date is today(8/5/16) and we add 5 business days it converts it to 120 hours. It then divides the hours by the business hours which is 12 business days and adds that to the created date which is incorrect.  Is there anyway to make the days convert to amount of time in a business day(which could be dynamic based on BusinessHours) instead of 5 business days being 5 24 hours days?  Heres the code we have currently:  Long interval = c.CreatedDate.addDays(Integer.valueOf(amountOfTimeString)).getTime() - c.CreatedDate.getTime(); c.SLA_Due_Date__c = BusinessHours.add(bh.Id, c.CreatedDate, interval);   I would wish to avoid dividing the interval by a magic number and have it instead be dynamic by the BusinessHours.  Any help would be great  BusinessHours API:    Edit: adding complete method of snippet  private static Boolean setDate(Object amountOfTime, Object timeType, Case c, BusinessHours bh, SObject referenceObject) {     Decimal amountOfTimeString = (Decimal) amountOfTime;     String timeTypeString = (String) timeType;     if(!String.isEmpty(String.valueOf(amountOfTimeString))) {         if(timeTypeString == 'Business Hours') {             Long interval = c.CreatedDate.addHours(Integer.valueOf(amountOfTimeString)).getTime() - c.CreatedDate.getTime();              c.SLA_Due_Date__c = BusinessHours.add(bh.Id, c.CreatedDate, interval);         } else if(timeTypeString == 'Calendar Hours') {             c.SLA_Due_Date__c = c.CreatedDate.addHours(Integer.valueOf(amountOfTimeString));         } else if(timeTypeString == 'Business Days') {             System.debug('Amount of time string: ' + amountOfTimeString);             Long interval = c.CreatedDate.addDays(Integer.valueOf(amountOfTimeString)).getTime() - c.CreatedDate.getTime();             System.debug('Created Date: ' + c.CreatedDate);             c.SLA_Due_Date__c = BusinessHours.add(bh.Id, c.CreatedDate, interval);         } else if(timeTypeString == 'Calendar Days') {              c.SLA_Due_Date__c = c.CreatedDate.addDays(Integer.valueOf(amountOfTimeString));         }          return true;     }     return false; }


I have debugged and try to figure out the cause from stacktrace but unable to find the reason of NullPointerException for this particular input. If I change the last input(marked in code) greater than 20, code executes successfully, but if its less than 20 then it throws exception.  package geeksforgeek.examples.sorting;  public class SinglyLinkedList {   Node head; Node current; public void add(int data){     if(head == null){         head = new Node(data);         current = head;         return;     }      while(current.next != null)         current = current.next;     current.next = new Node(data); }  public void print(Node node){     current = node;     while(this.current != null) {         System.out.print(" "+current.data);         current = current.next;     }     System.out.println(); }  static  class Node {     int data;     Node next;     Node(int data){         this.data = data;         this.next = null;     }  }  public static void main(String[] args) {      SinglyLinkedList quick = new SinglyLinkedList();     quick.add(30);     quick.add(3);     quick.add(4);     quick.add(20);     quick.add(15);     quick.add(55);     quick.add(35);     quick.add(65);     quick.add(25);     quick.add(95);     quick.add(85);     quick.add(75);     quick.add(2); /*issue with 2, less than 20 throw exception*/      Node node = quick.head;     while (node.next != null)         node = node.next;     quick.print(quick.head);     sort(quick.head, node);     quick.print(quick.head); }  public static void sort(Node low, Node high){     if(low==high)         return;          Node prePivot = partition(low,high);         sort(low,prePivot);         if(low != null && prePivot==low){             sort(prePivot.next,high);         }else if(prePivot != null && prePivot.next != null){             sort(prePivot.next.next, high);         } }  public static Node partition(Node low, Node high){      if(low == high || low == null || high == null)         return low;      Node prePivot = low;     Node current = low;     Node pivot = high;      while(low != high) {         if (low.data < pivot.data) {             prePivot = current;             int temp = current.data;             current.data = low.data;             low.data = temp;             current = current.next;         }         low = low.next;     }      int temp = current.data;     current.data = pivot.data;     pivot.data = temp;     return prePivot; }   }  Exception in thread "main" java.lang.NullPointerException     at geeksforgeek.examples.sorting.SinglyLinkedList.partition(SinglyLinkedList.java:86)     at geeksforgeek.examples.sorting.SinglyLinkedList.sort(SinglyLinkedList.java:67)     at geeksforgeek.examples.sorting.SinglyLinkedList.sort(SinglyLinkedList.java:72)     at geeksforgeek.examples.sorting.SinglyLinkedList.sort(SinglyLinkedList.java:68)     at geeksforgeek.examples.sorting.SinglyLinkedList.sort(SinglyLinkedList.java:70)     at geeksforgeek.examples.sorting.SinglyLinkedList.main(SinglyLinkedList.java:59)

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


The title explains most of it for you. I basically want a cursed crafting recipe   However, I want the resulting wooden pickaxe to be enchanted with sharpness (for absolutely no reason). I tried modifiying the .json file of the crafting recipe:  {     "type": "minecraft:crafting_shaped",     "pattern": [         "///",         " O ",         " O "     ],     "key": {         "/": {             "item": "minecraft:stick"         },         "O": {             "item": "minecraft:oak_planks"         }     },     "result": {         "item": "minecraft:wooden_pickaxe",         "count": 1,         "tag": {             "enchantments": [                 {                     "id":"minecraft:sharpness",                     "lvl": 32767                 }             ]         }     } }   However, it still did not work.  Any ideas?

I have a small question: does Minecraft 1.14.4 allow NBT tags in crafting recipes? Because I'm making a map in 1.14.3 and some part of the map need custom NBT tags crafting and I need to use custom crafting chest to make it


I am attempting to create a database connection and update using a prepared statement with JDBC to MYSQL.  I have tried changing the connection a bit and had to change the preparedStatement class to static in order to not get errors.  However, when running the app I got a NullPointerException error and I can't see where exactly I need to create a new object.  Currently, I get an error:     Exception in thread "main" java.lang.NullPointerException           at Alter.main(Alter.java:12)      import java.sql.PreparedStatement; import java.sql.SQLException;  public abstract class Alter {      public static void main(String[] args) throws SQLException {                   String query = "INSERT INTO school.students (First_Name, Last_Name, Gender, Grade_Level, IEP, Disruptive_1to5_LowtoHigh, OffTask_1to5_LowtoHigh, Not_Responsible_1to5_LowtoHigh, Not_GetAlong_1to5_LowtoHigh) VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?)";                  PreparedStatement myStmt = Connection.prepareStatement(query);                           myStmt.setString(1, "Chris");                     myStmt.setString(2, "Johnson");                     myStmt.setString(3, "Male");                     myStmt.setString(4, "K");                     myStmt.setString(5, "N");                            myStmt.setInt(6, 1);                     myStmt.setInt(7, 3);                     myStmt.setInt(8, 5);                     myStmt.setInt(9, 2);                     myStmt.addBatch();                      int[] result = myStmt.executeBatch();                      System.out.println(result + " were added to the database.");      } }   import java.sql.*;  public class Connection extends Alter {     {     try {          Class.forName("com.mysql.cj.jdbc.Driver").getDeclaredConstructor().newInstance();      }          catch (Exception ex) {          }     try {          batchInsertRecordsIntoTable();      } catch (SQLException e) {          System.out.println(e.getMessage());      } }      final static void batchInsertRecordsIntoTable() throws SQLException {         {             try {           DriverManager.getConnection(                      "jdbc:mysql://localhost:3306/school?allowPublicKeyRetrieval=true&useSSL=false&serverTimezone=UTC",                        "root", "");           System.out.println("Connection Successful"); }       catch (SQLException ex) {          ex.printStackTrace();      }         } }      public Statement createStatement() {         return null;     }      public static PreparedStatement prepareStatement(String query) {         return null;     } }


This integral I got from an MIT Bee Integral contest. The actual question is:     $$\displaystyle \int_{-\infty}^{\infty} e^{-2x^2-5x-3} \mathrm dx$$   So I look at the exponent and I see the factors so why not?  $\displaystyle \int e^{-(x+1)(2x+3)} \mathrm dx$  Then I go for the substitution:  $\begin{align}u&=x+1 \\ \mathrm du&=\mathrm dx \end{align}$  So we turn this into:  $\displaystyle \int e^{-u(2u+1)} \mathrm du$  $\displaystyle \int e^{-u} \cdot e^{-2u^2} \mathrm du$  So far so good. Yet another substitution because of some potential I saw.  $\begin{align} v&=e^{-u} \\ u&=-\ln v \\ \mathrm du&= -\dfrac{1}{v} \mathrm dv \end{align}$  The next transformation is:  $\displaystyle \int v \cdot e^{-2\ln^2 v} \cdot -\dfrac{1}{v} \mathrm dv$  $=\displaystyle \int -e^{-2\ln^2 v} \mathrm dv$  This is where I saw blanks. My question is: is this even the right way to go about this? If so please help out from here, otherwise any recommendations or ideas would be appreciated.   Lastly, if the method is easy for someone with scraps of Calc 2 knowledge just leave a hint because I want to own this thing. Thanks :)

How to prove  $$\int_{0}^{\infty} \mathrm{e}^{-x^2}\, dx = \frac{\sqrt \pi}{2}$$


If $X$ is a separable topological space, and $V$ is some dense subspace of it, is $V$ necessarily separable?

I'm trying to find an example of a non-separable subspace of a separable space.  What kind of examples are there?


How can I retrieve web search history on Google Chrome? My history data gets cleaned after 10 weeks. Is it possible to view the files? If so, how do I access them?

I'm trying to find a page I looked at months ago but it looks like it's disappeared off the face of the planet. I thought I would have better luck looking through my Google Chrome browsing history, but I can't see history past September. Can I force Google Chrome to display history further into the past? Can I retrieve the history manually from a directory? Is the history data gone?


I know it's definitely not okay to try to place unsolicited advertisements for Area 51 proposals (or anything else for that matter) in questions, answers, and comments. But what about a username, say "Area51BasketWeaving"? I'd really rather not see advertisements while trying to read real posts, but at the same time I don't want to stop people from picking their usernames.

Is it permissible to use your SE display name to advertise another SE site or Area 51 Proposal? Is this scrupulous or laudable?   I don't refer to my comment box. For example, could I change 'LePressentiment' to 'Commit to Law SE' to advertise the  proposal?


I received data saved as geodatabase from Esri (10.x) and want to open or work with it in Qgis 2.0.1. The files are like following    I read a lot in the site about this subject but I still have no idea how it could work.   Can somebody give me step by step advice?

I have spent around 2 days to find the way to open GDB (Esri geodatabase) in QGIS (or any other open source software) but still without success.  I have downloaded the newest OSGeo4W installer and tried the setup - express desktop install - all packages, as well as advanced install incl gdal-filegdb.  Can you describe a more detailed procedure, including installation and how to open .gdb in QGIS (OSGeo4W installation)?


The Statement: If a set of n balls contains a green ball then all the balls in the set are green. The proof:  The statement holds trivially for n = 1. Assume that the statement is true for n ≤ k. Take a collection $B_1$ of k + 1 balls that contains at least one green ball. From $B_{k+1}$, pick a collection $B_k$ of k balls that contains at least one green ball. Then by the induction hypothesis, each ball in $B_k$ is green. Now, remove one ball from $B_k$ and put the ball which was left out in the beginning. Call it $B_k'$. Again by the induction hypothesis, each ball in $B_k'$ is green. Thus, each ball in Bk+1 is green. Hence by PMI, our proof is complete.  What's the error?

I'm bugged by the following that's summarized on p. 109 of .     False theorem: All horses are the same color.      Proof by induction:      $\fbox{$P(n)$ is the statement: In every set of horses of size $n$, all $n$ horses are the same color.}$   $\fbox{Base Case or $P(1)$:}$ One horse is the same color as itself. This is true by inspection.   $\fbox{Induction Step:}$ Assume $P(k)$ for some $k \geq 1$.   $\fbox{Proof of $P(k + 1) :$}$   Since $\{H_1, H_2, ... , H_n\}$ is a set of $n$ horses, the induction hypothesis applies to this set. Thus, all the horses in this set are the same color.   Since $\{H_2, H_3, ... , H_{n+1}\}$ is also a set of $n$ horses, the induction step likewise holds for this set. Thus, all the horses in this set are the same color too.         Therefore, all $n +1$ horses in $\{H_1, H_2, H_3, ... , H_n , H_{n+1}\}$ are the same color. QED.   The issue the instructor was trying to point out is clearly valid. For the case $n = 1$, there is only ${H_1}$. So this case says nothing about possible overlapping elements of each set of $(n + 1)$, for instance $H_2$ in the above proof.    But it was proposed in the class discussion that this was the only problem. Had you been able to prove $P(2)$ true, then a proof of the above format would have been fine.    My interpretation is that yes, you could prove all horses are the same color, if you can prove that any set of two horses will be the same color. But this format would not work.  Why not? The problem I see is that the above proof is for the existence of at least one particular pair of sets of horses of sizes $n$ and $n + 1$, such that in each set, all horses are the same color.  Particularly when the set of size $n$ is a subset of the set of size $n + 1$.  In order to prove the induction step, don't you need to prove that sets of sizes $n$ and $n + 1$, do not necessarily contain the same, overlapping elements?  You could prove that any horse can be added to a set of 2 horses.  Take the last two, and they must be the same color, and so on.  Wwhatever color the first two happen to be, all other horses must thus be the same color.    Am I misinterpreting the example, or am I making a logical error? Thanks in advance.


I'm trying to get a command block to open up Netflix when i activate it. If the link is "", then what should the command be? P.S. I want the text to be red and not underlined.

I have seen links in servers that can send you to a page in a browser, is there any way to replicate this with command blocks?  I don't mean command links, I mean web pages.


I did a clean install of Windows 10 and logged in with my Microsoft account which clearly has my full name. Somehow the personal folder where My Documents etc. are stored is named after the first 5 characters of my email account and not my first name.  Some apps which rely on profile information from the system also directly identify me using the first 5 characters of my email address, instead of my real name, which is really annoying.  I Googled a bit and  facing the same issue.  Here are some sample images (not mine) to illustrate the issue from the aforementioned person, who has his folder named "dhubb" instead of "Dick":      How did this happen? Is there any way I can change it back to my name without having to reinstall my system again (which is not guaranteed to work)?

After installing Windows 10 on my  it took my user name 'Jeremy' and created a user folder named C:\Users\jerem.  I want to rename the folder C:\Users\Jeremy.  does not work. There are a couple of reasons.   OneDrive is now a fully integrated part of the OS, and it completely breaks.  A find/replace in the registry seems to work, but it's hard to be confident in that approach. When the computer is rebooted, the TabletInputService writes a TextHarvester.dat file to the old user profile location (creating it if needed). This makes it impossible to keep the folder deleted. An old  doesn't work. This issue also causes an error message to pop up every time the computer boots.


Is it meaningful in the sense of falsificable to ask whether the whole universe (including everything known/observable: cosmic background radiation etc ..., excluding everything not directly observable like dark energy) is rotating? Naively you would say, sure you can measure centrifugal forces. But centrifugal fictitious forces are defined with respect to a background in Newton's mechanics or indirectly as geometry in Relativity. Somehow I did get from Newton's bucket to headlines like "the universe is spinning". I am confused. E.g. in "Shape Dynamics" (Although the question has nothing to do with Shape Dynamics!) as far as I understood the rotation of the universe as a whole is dismissed as unobservable. Please correct me if I am wrong! Note again: Shape Dynamics has nothing to do with this question.

Suppose in the milliseconds after the big bang the cosmic egg had aquired some large angular momentum. As it expanded, keeping the momentum constant (not external forces) the rate of rotation would have slowed down, but it would never reach zero.  What implications would that have to measurments to distant supernova and CMB radiation? Do we have any experimental data that definitely rules out such as scenario? And to what confidence level?  Edit A  suggests that the universe might indeed be spinning as a whole. Anyone care to poke holes at it?  Edit 2 Even more  places limits on possible rotation.


I was reviewing some of my grade 12 calc stuff today, and I thought of this question that I can't seem to answer.  Say I have a piecewise function $f(x) = \begin{cases} x=6, & x<1; \\ x=7, & x \ge 1.\end{cases}$  Therefore, $ \lim f'(x)_{x\to1^-} = 0 $ and $ \lim f'(x)_{x\to1^+} = 0 $. However, $f(x)$ is not continuous on x = 1, and I've learned in school that it is not possible for a function to be differentiable and not continuous. So Why isn't this function differentiable?

I have a question, to aid my understanding, about the proof that differentiability implies continutity.$\mathstrut$    Differentiability Definition  When we say a function is differentiable at $x_0$, we mean that the limit:  $$f^{\prime} (x) = \lim_{x\to x_0} \frac{f(x) - f(x_0)}{x-x_0}$$ exists.  Continuity Definition  When we say a function is continuous at $x_0$, we mean that: $$\lim_{x\to x_0} f(x) - f(x_0) = 0$$  Theorem: Differentiability implies Continuity: If $f$ is a differentiable function at $x_0$, then it is continuous at $x_0$.  Proof:  Let us suppose that $f$ is differentiable at $x_0$. Then $$ \lim_{x\to x_0} \frac{f(x) - f(x_0)}{x-x_0} =  f^{\prime} (x) $$  and hence  $$ \lim_{x\to x_0} f(x) - f(x_0) = \lim_{x\to x_0} \left[ \frac{f(x) - f(x_0)}{x-x_0} \right] \cdot \lim_{x\to x_0} (x-x_0) = 0$$  We have therefore shown that, using the definition of continuous, if the function is differentiable at $x_0$, it must also be continuous.  My Question  The proof seems to execute the following steps:   Assume the function is continuous at $x_0$ Show that, with little algebra, we can change this into an equivalent question about differentiability at $x_0$. With this little bit of algebra, we can show that if a function is differentiable at $x_0$ it is also continuous.   What I am slightly unsure about is the apparent circularity. In my mind it seems to say, if a function is continuous, we can show that if it is also differentiable, then it is continuous. Rather than what I was expecting, namely, if a function is differentiable, we can show it must be continuous.  Hopefully my confusion is clear. Any help will be greatly appreciated.


Is there any program that logs the CPU usage of all programs? I want to know, over a period of one month, which programs use the CPU more intensely.

Is there any easy way on Windows to log %CPU time per process over time to a file for later analysis?  As far as I can see...   Task manager shows me the %CPU per process but only visually - no way to save to a file. Perfmon will let me save to a file, and will additionally create a time-based file (taking snapshots at specified time intervals) - which is almost what I want, except that as far as I can see it can't break down the %CPU by process. Process Explorer will let me break down by process, but it will only save the file as a snapshot of a single point in time   So, none of these are quite what I need: I need to get a file that contains something like 'top 10 processes by CPU, every 15 seconds, until I stop the monitoring' The reason I need this because I have a machine on which some process is causing occasional brief spikes in CPU usage several times a day and I need to find out which process is the culprit.    Can anything do that, or have I missed some feature of perfmon or process explorer?


i want to check the type of uploaded file. If name like example.txt, i want to get the .txt part only. How can i achieve it using Jquery or javascript.  Any Suggestions or links would be appreciative!!!

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


I'm implementing a doubly linked list with a Previous() function that raises a NullPointerException, I would appreciate help if someone knows how to fix this. The error is in line 37 of the parent class (DoublyLinkedList).  I'm a beginner taking (a beating from) a course on data structures and java. A friend helped me by saying the following "It says that your null pointer exception is at your .Previous() function [line 18]. I looked at your Previous() function within your DoublyLinkedList class and it seems that you don't check if current == null before testing if current != head. YOu must have a null case so that you don't get a nullpointer like in your case. If your current == null, you should set it to the tail, otherwise keep the rest of our code." I tried fixing that but still have the same problem   class Node {     // Public references to previous and next nodes     public Node next;     public Node previous;      // Private data field     Object data;      public Node(Object data)     {         this.data = data;     }      public Object GetData()     {         return data;     } }  class DoublyLinkedList {     Node head;     Node tail;     Node current;     Node next;     Node previous;       // Go to the first element in the list      public void Head()     {         current = head;         previous = null;         }      //Go to the last element in the list     public void Tail()     {         current = tail;         next = null;     }      // Go to the next element if the current element is not past-the-end     public void Next()     {         if (current != null)         {             previous = current;             current = current.next;         }     }      public void Previous()     {         if (current == null && current != head)             next = null;             Tail();         if (current != head)         {             next = current;             current = current.previous;         }     }      // Return the data associated with the current element     // or null if the current element is past-the end     public Object Get()     {         return current == null ? null : current.GetData();     }      // Insert a new element before the current element     // or at the end if the current element is past-the-end     public void Insert(Object data)     {         // Create new node         Node node = new Node(data);          // Set 'next' reference of new node         node.next = current;          // Set 'next' reference for 'previous' node.         // Treat the special case where the current node is the head.         if (current == head)             head = node;         else             previous.next = node;          // Update current node         current = node;     }         public void Print()     {         // Traverse list         for (Head(); Get() != null; Next())             System.out.println(Get());     } }  class Test {     public static void main(String args[])     {         // Create list         DoublyLinkedList doubly_linked_list = new DoublyLinkedList();          // Insert elements at the end         doubly_linked_list.Insert("a");         doubly_linked_list.Next();         doubly_linked_list.Insert("b");         doubly_linked_list.Next();         doubly_linked_list.Insert("c");         doubly_linked_list.Next();          // Set second-to-last as current element. Insert string "d"         doubly_linked_list.Tail();         doubly_linked_list.Previous();         doubly_linked_list.Insert("d");          // Set current element as past-the-end. Insert string "e"         doubly_linked_list.Tail();         doubly_linked_list.Next();         doubly_linked_list.Insert("e");          // Print         doubly_linked_list.Print();     } }

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


I'm trying to create a list object that stores and sort either integer or string, but the input could also be a list i.e I would like to create it with a = SortedList(5) or a = SortedList([7, 5, 8])   class SortedList:      def __init__(self, element):          self.list = []          if type(element) == "int" or type(element) == "str":             self.list = self.list +[element]          if type(element) == "list":             self.list = self.list + element          self.list.sort()   When my object is instantiate all I get is my empty list, my if statement is not taken into account. Any ideas please ?

What is the best way to check whether a given object is of a given type? How about checking whether the object inherits from a given type?  Let's say I have an object o. How do I check whether it's a str?


Below is my mysql table. CREATE TABLE `mydb`.`mytable` ( `id` INT NOT NULL AUTO_INCREMENT, `comment` VARCHAR(100) NOT NULL , PRIMARY KEY (`id`)) ENGINE = MyISAM;  ALTER DATABASE mydb CHARACTER SET = utf8mb4 COLLATE = utf8mb4_unicode_ci;  ALTER TABLE mytable CONVERT TO CHARACTER SET utf8mb4 COLLATE utf8mb4_unicode_ci;  Below is my php code. <?php     if(isset($_POST["submit"])){         $con = mysqli_connect("localhost","root","","mydb");         $comment = mysqli_real_escape_string($con, $_POST['comment']);         $sql="INSERT INTO `user`(`comment`) VALUES ('".$comment."')";         if (mysqli_query($con, $sql)) {             echo "New record created successfully";           } else {             echo "Error: " . $sql . "
" . mysqli_error($con);           }     } ?>                    <form method="POST">             <input type="text" name="comment">             <input type="submit" value="submit" name="submit">         </form>        when I try to submit with emojies in localhost, unknown characters were stored (inserted) in localhost. when I try to submit with emojies in 000webhost.com, no records were inserted to the database. But I can store emojies directly in both database(localhost & 000webhost.com) by executing following sql command directly in mysql server(PHP MYADMIN). INSERT INTO `mytable`(`comment`) VALUES ('😜');  But I couldn't insert emojies using PHP. So my question is how to insert emojies using PHP to mysql server?

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


I deleted my question from Stack Overflow having some sensitive information, but I believe the question is not completely removed from Stack Overflow. It also has a revision history, so I want to remove all the data related to it - snapshot everything. Could anyone properly help me to resolve this matter?

I've observed several incidents where users inadvertently posted detailed, sensitive information. For example, a Server Fault user who posted a question with working login credentials to his actual production server, or the Stack Overflow user who posted actual medical records as example data for his question.   What should be the procedure for handling such cases?


I am new to LaTex and I need some help with equation numbering format when I use the cmd of begin{equation} it gives me equation number as (2.1) how can I change it so it gives me equation as (1) (2) ... and so on..

Some document elements (e.g., figures in the book class) are numbered per chapter (figure 1.1, 1.2, 2.1, ...). How can I achieve continuous numbering (figure 1, 2, 3, ...)?  And vice versa: Some document elements (e.g., figures in the article class) are numbered continuously. How can I achieve per-section numbering?  \documentclass{book}% for "vice versa" variant, replace `book` with `article`  \begin{document}  \chapter{foo}% for "vice versa" variant, replace `\chapter` with `\section`  \begin{figure} \centering \rule{1cm}{1cm}% placeholder for graphic \caption{A figure} \end{figure}  \end{document}   Bonus question: Is it possible to adjust the numbering of the sectioning headings themselves? Can I, e.g., switch from per-chapter to continuous numbering of sections in the book class?


I have a Yoga 2 11( model 20428) and Win8.1 takes about 2 of my 4gb of RAM to run.  How much RAM will Ubuntu use to run.  This is a secondary laptop, for movie watching, school work, websurfing and etc.   nothing too hardcore.

For a given hardware configuration, how do I find out if Ubuntu will run on it? What considerations should I take into account when choosing an Ubuntu version and  such as:    with a lighter desktop than the usual Gnome and Unity  with the even lighter LXDE desktop   Obviously Ubuntu does not run on some processor architectures. So how do I go about choosing the right version and derivate. How can I find out the minmal system requirements?


In order to be able to find an antiderivative, I have been taught to decompose fractions by first observing an identity, like $$\frac{2x+1}{(3x-2)(x+1)} \equiv \frac{A}{3x-2}+\frac{B}{x+1}$$ wherever the function is defined.  Then I would expand and substitute, like so: $$A(x+1)+B(3x-2) \equiv 2x+1$$ letting $x=-1$: $$-5B=-1 \implies B=\frac{1}{5}$$ and then letting $x=\frac{2}{3}$: $$\frac{5}{3}A=\frac{7}{3} \implies A= \frac{7}{5}$$  Why are these substitutions justified? In both cases the original function is undefined for these $x$ values as the denominator would be zero - does this mean my claim "wherever the function is defined" is unnecessary? I can't see why this gives the right answer, but it does (as I can verify by matching coefficients instead of substituting)!

This may be an incredibly stupid question, but why does partial fraction decomposition avoid division by zero?  Let me give an example:  $$\frac{3x+2}{x(x+1)}=\frac{A}{x}+\frac{B}{x+1}$$  Multiplying both sides by $x(x+1)$ we have:  $$3x+2=A(x+1)+Bx$$  when $x \neq -1$ and $x \neq 0$.  What is traditionally done here is $x$ is set to $-1$ and $0$ to reveal: $$-3+2=-B \implies 1=B$$ and  $$2=A$$  so we find that   $$\frac{3x+2}{x(x+1)}=\frac{2}{x}+\frac{1}{x+1}$$  Why can $x$ be set equal to the roots of the denominator (in this case, $0$ and $-1$) without creating a division by zero problem?


I'm using a template from overleaf and the subfigure caption appear always Uppercase.  I've tried \renewcommand*{\thesubfigure}{\alph{subfigure}} and also \renewcommand*{\thesubfigure}{\roman{subfigure}} but nothing changes, still appearing uppercase.  Any idea what can be affecting this? I've looked for subfigure, caption, Alph, but I've not found anything.  Thank you.

I seem to be having a unique problem. There are many questions asking about how to change subcaption to a label with capital letters but for me my program is defaulting to capital letters when I would prefer lowercase.  My preamble  \documentclass[12pt,reqno]{amsart} \setlength\parindent{0pt} %no auto indentation for new paragraphs \usepackage{geometry}  \geometry{a4paper}  \usepackage{natbib}  \usepackage[latin1]{inputenc} \usepackage{amsmath, amsthm, amssymb, calc, dsfont}    \usepackage{enumerate} \usepackage{subcaption, caption, graphicx} %figure packages \usepackage{authblk} %author affiliations \usepackage{setspace, lineno} %double spaced etc. options, line numbering  \usepackage{tikz} \usetikzlibrary{shapes,arrows,chains,automata,positioning}   My figure  \begin{figure}[h!]   \centering   \begin{subfigure}[]{0.48\textwidth}           \includegraphics{Figure1.pdf}           \caption{}           \label{FigPractice}    \end{subfigure}    \begin{subfigure}[]{0.48\textwidth}           \includegraphics{Figure2.pdf}           \caption{}           \label{PracticeAge}   \end{subfigure}   \caption{a caption} \end{figure}   I've also tried \renewcommand{\thesubfigure}{\alph{subfigure}}


Empowered Evocation (PHB 177) reads:     Beginning at 10th level, you can add your Intelligence modifier to the damage roll of any wizard evocation spell you cast   The spell Ice Storm does 2 different types of damage:     A creature takes 2d8 bludgeoning damage and 4d6 cold damage on a failed save, or half as much damage on a successful one   I have an evoker with a 16 intelligence (+3 modifier). I cast Ice Storm as 4th level. Is my int bonus added to:   The total damage: 2d8 + 4d6 + 3 Each damage type: 2d8 + 3 and 4d6 + 3

I'm playing a Shadow sorcerer/ and I am rather confused about the Hexblade's Curse feature (Xanathar's Guide to Everything, p. 55). It says, on the first bullet point of the curse details:     You gain a bonus to damage rolls against the cursed target. The bonus   equals your proficiency bonus.   What exactly is a damage roll? Is it the cumulative rolling of all dice, is it a roll of one or more of the same die type, or is it a single roll of a damage die?


I have many times come across this word. I even know a little about it but don't know exactly what it is.

What is the difference between:   Unlocking the bootloader (prerequisite for doing many, though not all, other things below) Rooting Jailbreaking ROM NAND and Nandroid Operating System Mod (e.g. CyanogenMod) Recovery (ClockworkMod, Amon Ra) Custom Kernel (e.g. LeshaK's kernel) Firmware Driver Over The Air (OTA) update Fastboot SIM unlocking Flashing SPL (Second Program Loader)   (any other often-confused terms that I've missed?)


I want to use Context in the static class below in the do in background method. I have tried parsing context in the constructor and also creating an instance of the class but every time I get this error :  Attempt to invoke virtual method java.io.File android.content.Context.getCacheDir() on a null object reference       public static class PopulateDbAsyncTask extends AsyncTask<Void, Void,        Void> {         private PicDao picDao;         Context context;          public PopulateDbAsyncTask(PictureDataBase db, Contex context) {             picDao = db.picDao();             this.context = context;          }          @Override         protected Void doInBackground(Void... voids) {             RequestQueue mRequestQueue = Volley.newRequestQueue(context);             return null;          } }

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


My grammar book says that both present perfect and present perfect continuous, when used with "for, since, etc", express a situation that began in the past and continues to the present. When used without 'since' or 'for', present perfect expresses the action that has happened before now and the progressive without any specific mention of time expresses a general activity in progress recently.     So neither of them implies that an action is still in progress when time is not mentioned, but I noticed that sometimes even when specific time is mentioned both can refer to an activity that is not in progress anymore and that has finished. Eg., I have been wearing this dress/I have worn this dress the whole summer. (The summer is over, the action is over too) What do you think about it? I can give another example; I have been living in France (Maybe the person has just relocated and says that he has been living in France recently) and I have been living in France my whole life/for five years/for ages(Again the person has relocated to another location and says where he/she used to live recently. I have lived in France my whole life/for five years/for ages. Similar statements as the two above: he/she doesn't live there anymore, but was recently living there. Sometimes native speakers tell me that nothing is impossible :).   What do you think about these statements?  I have been driving my car. The specific time is not mentioned, however the progressive form  implies that the action is still in progress. I have been confused by this sentence too as well as by the sentences below.  I have been driving my car for ages/for five years. I know that this normally means I am still driving it, but I have been told (not by experts) that it can also imply that the action has finished recently or even if not recently it is not in progress anymore. The following  sentence has the same meaning as the previous one;  I have driven my car for ages/for five years. And They have been married for twenty years/for ages, maybe they are still married, maybe have recently divorced.  Are these comments right? Thanks

I have studied "present perfect" and "present perfect continuous" for a week. I know forms, verb and helping verb I should use when I write them.  For me, they have nearly same definition because I can use them interchangeably in Thai language. (My native language)  For example, the sentences        I have learned English language in the past few weeks.    I have been learning English language in the past few weeks.       have no difference in meaning to me. They both mean "I began learning the English language in the past and I am still learning it"  Can I use them interchangeably in English? Or is there any difference between them? For example, when should I use present perfect but not present perfect continuous?


How can i install suggested programs, twice? I just did an apt get install and a list of packages were suggested. Thats fine. I went ahead and added --install-suggests, however during installing the suggested programs, even more suggestions came up, how do i install those? Ill have a go and run it again see if that works Working in ubuntu 20.04 server whilst installing the first suggested packages, even more packages were suggested for the first set of suggested packages

I know the question has been asked before, but please hear me out. So I wanted to install screenlets. I ran sudo apt-get install screenlets, and this is what I got:  The following extra packages will be installed:   libart-2.0-2 libbonobo2-0 libbonobo2-common libbonoboui2-0 libbonoboui2-common libgnome2-0 libgnomecanvas2-0   libgnomecanvas2-common libgnomeui-0 libgnomeui-common libtidy-0.99-0 python-beautifulsoup python-evolution   python-feedparser python-gmenu python-gnome2 python-numpy python-pyorbit python-rsvg python-tz python-utidylib   screenlets-pack-basic Suggested packages:   libbonobo2-bin python-gnome2-doc python-numpy-doc python-numpy-dbg python-nose python-dev gfortran   python-pyorbit-dbg screenlets-pack-all python-dcop Recommended packages:   python-numeric python-gnome2-extras The following NEW packages will be installed:   libart-2.0-2 libbonobo2-0 libbonobo2-common libbonoboui2-0 libbonoboui2-common libgnome2-0 libgnomecanvas2-0   libgnomecanvas2-common libgnomeui-0 libgnomeui-common libtidy-0.99-0 python-beautifulsoup python-evolution   python-feedparser python-gmenu python-gnome2 python-numpy python-pyorbit python-rsvg python-tz python-utidylib   screenlets screenlets-pack-basic 0 upgraded, 23 newly installed, 0 to remove and 2 not upgraded.   People say that Recommended packages are installed by default, but they are clearly not included in the NEW packages that will be installed above. I also decided to include the Suggested packages in the installation, so I ran sudo apt-get --install-suggests install screenlets instead, but I got a HUGE list of NEW packages that will be installed; that number is precisely 0 upgraded, 944 newly installed, 0 to remove and 2 not upgraded. Should'nt I be getting only around 10 extra packages?


I've made a game in 1920x1080 res in XNA, and I can't seem to find a way for the graphics device to squash the screen images to other resolutions like 1600x900 when played on different computers.  How can I get my game to be in proportion, and fit on smaller screens with the same aspect ratio?

I'm working on a simple 2D game. I've finished the mobile phone version.  However, my boss wants the game to works on his RT. I'm doing the "conversion" but my buttons are in the wrong places, because I hard-coded the screen size, like this:   texture = game.Content.Load<Texture2D>("StartScreen");  mainFrame = new Rectangle(0, 0, game.GraphicsDevice.Viewport.Width, game.GraphicsDevice.Viewport.Height);   // button definitions  startbrect = new Rectangle(300, 258, 88, 88);  startbtext = game.Content.Load<Texture2D>("bplay");   In this example, mainframe is fine, but startbrect isn't, because I defined the size to match a Windows phone's screen. How can I handle responsive design when all Windows 8 phones' screens are different? Is there a formula or macro to calculate each time the good size?


If I have a class with constants for example AppConstants and use  public static final variable from there like AppConstants.MY_STRING it would recreate this class all the time or it creates it during runtime because the fields in the class is static? So is it better to define file in constants or "at the place"?

To be specific, I was trying this code:  package hello;  public class Hello {      Clock clock = new Clock();      public static void main(String args[]) {         clock.sayTime();     } }   But it gave the error      Cannot access non-static field in static method main   So I changed the declaration of clock to this:  static Clock clock = new Clock();   And it worked. What does it mean to put that keyword before the declaration? What exactly will it do and/or restrict in terms of what can be done to that object?


I'm trying to write a unit test that detects an invalid use of the lock() feature of my class. In order to do so, I want to use the destructor and throw an exception from there. Unfortunately, instead of catching the exception, g++ decides to call std::terminate().  There is a very simplified version of the class:  class A { public:     A() : f_lock(0) {}     ~A() { if(f_lock) throw my_exception("still locked"); }     lock() { ++f_lock; }     unlock() { --f_lock; } private:     int f_lock; };   There is a valid test:  A *a = new A; a->lock(); ... a->unlock(); delete a;   There is the invalid test I'm trying to write:  A *a = new A; a->lock(); ... bool success = false; try {     delete a; } catch(my_exception const&) {     success = true; } catch(...) {     // anything else is a failure } if(!success) {     // test failed...     CPPUNIT_ASSERT(!"test failed"); }   Right now, the delete calls std::terminate() even though the throw is not being called when another exception is active. (i.e. std::uncaught_exception() is false.) And also I clearly am catch all exceptions!  Am I doing something wrong, or is g++ programmed to do that always in destructors?    Update:  The answer by dyp in the comments below works! The following does not directly call std::terminate():      ~A() noexcept(false) { throw ...; }   Also for reference about why you do not want a throw in a destructor, this page is excellent;      For clarification, there is the full version of the destructor. As we can see I first post a message (it generally goes in your console, may go to a log too). Second I make sure we're not already managing an exception. Finally, I throw an exception named exception_exit which is expected to force a terminate() although in a GUI application you may want to show a MessageBox of some sort to let the user know something happened (since you can capture the Message, you can display that to the user) and then force an application shut down.  Node::~Node() noexcept(false) {     if(f_lock > 0)     {         // Argh! A throw in a destructor... Yet this is a fatal         // error and it should never ever happen except in our         // unit tests to verify that it does catch such a bug         Message msg(message_level_t::MESSAGE_LEVEL_FATAL, err_code_t::AS_ERR_NOT_ALLOWED);         msg << "a node got deleted while still locked.";          // for security reasons, we do not try to throw another         // exception if the system is already trying to process         // an existing exception         if(std::uncaught_exception())         {             // still we cannot continue...             std::abort();         }          throw exception_exit(1, "a node got deleted while still locked.");     } }   Also, another detail, you are expected to use the NodeLock object to manage the f_lock flag. That is exception safe since it uses RAII (i.e. a scoped lock). However, at this point I did not want to force the user to make use of the NodeLock to lock/unlock a node, hence this test in the destructor.

Most people say never throw an exception out of a destructor - doing so results in undefined behavior. Stroustrup makes the point that "the vector destructor explicitly invokes the destructor for every element. This implies that if an element destructor throws, the vector destruction fails... There is really no good way to protect against exceptions thrown from destructors, so the library makes no guarantees if an element destructor throws" (from Appendix E3.2).   seems to say otherwise - that throwing destructors are more or less okay.  So my question is this - if throwing from a destructor results in undefined behavior, how do you handle errors that occur during a destructor?  If an error occurs during a cleanup operation, do you just ignore it? If it is an error that can potentially be handled up the stack but not right in the destructor, doesn't it make sense to throw an exception out of the destructor?  Obviously these kinds of errors are rare, but possible.


As the title already indicates, I have a problem with the page numbering.  At first I am in roman numbering mode and then I switch to arabic. But even though my \pagenumbering{arabic} statement is after my \listoftables command, the list of tables has the pagenumber 1.  \documentclass[10pt,a4paper,headsepline,footsepline,DIV13,BCOR12mm]{scrbook} \usepackage[english,ngerman]{babel} \usepackage[T1]{fontenc} \usepackage[latin1]{inputenc} \usepackage{scrpage2} \pagestyle{scrheadings} \usepackage{graphicx} \usepackage{hyperref} \usepackage[toc,numberedsection]{glossaries} \makeglossaries \newacronym{fap}{FAP}{Fundamental Architectural Principles}  \begin{document}  \selectlanguage{ngerman} \thispagestyle{empty}  \begin{table}[h] \centering \begin{tabular}{ccc} \hspace{0.7cm} & \end{tabular} \end{table}  \vspace{8mm} \begin{center} {\Large {\bfseries \scshape Institut Software \&  Engineering}\\  6a \hspace{0.25cm} D- \\ } \end{center}  \vspace{1cm} %title \begin{center} {\Huge \bfseries asd  \\[2mm] in   \\[5mm] asdasd } \end{center}  \vspace{1.5cm} %author \begin{center} {\Large Christian Vaas} \end{center}  \vspace{1cm} \begin{center} {\Large \bfseries Masterarbeit  Software Engineering} \end{center}  \vspace{1cm} \begin{center} \includegraphics[width=.4\linewidth]{img/logos/LogoSEengl} \end{center}  \newpage \thispagestyle{empty} \mbox{} \newpage \thispagestyle{empty}  \begin{table}[h] \centering \begin{tabular}{ccc} \hspace{0.7cm} & \end{tabular} \end{table}  \vspace{1cm} \begin{center} {\Large {\bfseries \scshape Institut Software \& Systems Engineering}\\  6a \hspace{0.25cm} D- \\ } \end{center}  \vspace{2.5cm} %title \begin{center} {\Huge \bfseries  Patterns \\[2mm] in   \\[5mm]  Architectures} \end{center}  \vspace{1cm} %author \begin{center} \begin{table}[h] \centering \begin{tabular}{ll} Matrikelnummer: &  \\ Beginn der Arbeit: & XX.\ X. XXX 20XX \\  Abgabe der Arbeit: & XX.\ X.XXX 20XX \\ Erstgutachter: & Prof.\ Dr.\ \\ Zweitgutachter: & Prof.\ Dr.\ YYY YYYYYY \\ Betreuer: &  S.  \\ \end{tabular} \end{table} \end{center}  \vspace{1.25cm}  %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% %%% Statement-Page \newpage \thispagestyle{empty} \mbox{} \newpage \thispagestyle{empty}  \centerline{\bfseries ERKLAERUNG}  \vspace{5cm} Hiermit versichere ich, dass ich diese Masterarbeit selbstaendig verfasst habe. Ich habe dazu keine anderen als die angegebenen Quellen und Hilfsmittel verwendet.  \vspace{1cm} \begin{flushleft} %select german for formatting the date \selectlanguage{ngerman} Augsburg, den \today \hfill ZZZ ZZZZZZ \end{flushleft}  \newpage \thispagestyle{empty} \mbox{}   \newpage  %select english as language! \selectlanguage{english}  \vspace*{1cm} \section*{\centering Abstract} \vspace{1cm}  \paragraph*{CONTEXT}  \pagenumbering{roman}  \tableofcontents \newpage \listoffigures \newpage \listoftables  \pagenumbering{arabic}  \chapter{Introduction} \section{Motivation/Challenges} \section{Approach} Blubber \gls{fap}  \printglossaries  \end{document}

In my Master thesis, I would like to have the title page without any page number and an acknowledgments section and the table of contents with roman numbers. The rest of the document should be numbered arabic.  I have tried this, to have roman numbers for the Table of contents and normal numbers for the rest.  \documentclass[12pt,ngerman,openany]{report} \usepackage{titlesec} \usepackage{titletoc} \usepackage{cite} \usepackage[a4paper]{geometry} %\usepackage[T1]{fontenc} \usepackage[utf8]{inputenc} \usepackage[ngerman]{babel} %\usepackage{ngerman}{babel} \usepackage[T1]{fontenc} \usepackage{graphicx} \usepackage{float} \selectlanguage{ngerman} \usepackage{amssymb} \usepackage{amsmath} \usepackage{url} \usepackage{epstopdf} \usepackage{scrhack} \usepackage{listings} \usepackage{caption} \titleformat{\chapter}{\rmfamily\huge}{\textbf\thechapter.}{25pt}{\huge\textbf} \defcaptionname{ngerman}{\lstlistingname}{Code} \defcaptionname{ngerman}{\lstlistlistingname }{Codeverzeichnis}  \lstloadlanguages{R}  \lstset{% general command to set parameter(s)    basicstyle=\sffamily\footnotesize, % print whole listing small    keywordstyle=\sffamily\footnotesize\bfseries, % ubold black keywords    identifierstyle=, % nothing happens    commentstyle=\sffamily\footnotesize\slshape, % green comments    stringstyle=\sffamily\footnotesize, % typewriter type for strings    showstringspaces=false, % no special string spaces    numbers=left,    numberstyle=\sffamily\footnotesize,    stepnumber=1,    numbersep=10pt,    showspaces=false,    showtabs=false,    frame=lines,    morecomment=[l]{\%},    float=htbp,    numberbychapter=true  }   \begin{document} \let\cleardoublepage\clearpage   \pagenumbering{roman}  \tableofcontents  \clearpage  \vspace*{75mm} \chapter{Einleitung} \section{Motivation} bla bla bla \section{Ziel}  bla bla \chapter{Stand der Technik zur Mustererkennung} \section{Die Zeitreihen} bla bla \subsection{Beschreibung} bla bla \subsection{Erklärung}  bla bla  \subsection{Vorhersage} bla bla \subsection{Kontrolle} bla bla \section{Feature Extraktion} bla bla \subsection{Autokorrelation} \subsection{Was ist Autokorrelation?} bla bla   \subsection{Autokorrelation und Zeitreihen} bla bla  \subsubsection{Zeitreihe-Diagramm}  bla bla \subsubsection{Lagged Streudiagramm} bla bla  \subsubsection{Autocorrelation-Function (Korrelogramm)} bla bla \subsection{Spektralanalyse} \subsection{Was ist Spektral-Analyse} bla bla \end{document}


Suppose I have this Student class:  public class Student {     public int StudentID { set; get; }     public string StudentName { set; get; }     public int Age { set; get; } }   I like to create collections of Students using List:  List<Student> studentList2 = new List<Student>() {     new Student() { StudentID = 1, StudentName = "John", Age = 18 } ,    new Student() { StudentID = 2, StudentName = "Steve",  Age = 15 }  };   But I've heard that it's usually better to use IList:  IList<Student> studentList1 = new List<Student>() {      new Student() { StudentID = 1, StudentName = "John", Age = 18 } ,     new Student() { StudentID = 2, StudentName = "Steve",  Age = 15 } };   I don't understand why people recommend using IList<Student> instead of List<Student>!  Is it some kind of performance concern? Is it optional and down to personal preference? Or is there another reason?

Can anyone explain to me why I would want to use IList over List in C#?  Related question:


Noob here, I've been researching on how to fix these problems for days now and I can't find exactly what I need to know, I need a walkthrough.  I'm trying to install Steam and here's what I get:  E: unable to locate package libgl1-mesa-dri:i386 E: Unable to locate package libgl1-mesa-glx:i386 E: Unable to locate package libc6:i386   Press return to continue:  After that, this pops up:`  You are missing the following 32-bit libraries, and Steam may not run: libc.so.6   So after doing lots of research I found I needed to download these packages or something, so i tried to, sudo apt-get , I got back that sudo apt-get command not found. So I've been researching and researching and I jut can't figure out what exactly I should do. Some people have gone into some details about different things to do but I'm completely lost.  If there's any information I should provide, let me know, I'm on chromebook running crouton, xfce4.

I have recently moved over from SteamOS which is Debian Wheazy. None of the other fixes have not worked, I tried getting steam both through Steam itself and the Ubuntu Center.


Because in a typical digital camera, each pixel records only one color though use of a Bayer filter or similar mechanism to achieve color vision, the true resolution of a ## megapixel sensor is actually lower, even after interpolation is applied.  Does anyone have any data on what the true effective resolution is and how this is determined?  I saw multiple posts online which said it's reduced by 1 / sqrt(2), but they offered no explanation of why this is the case.  Assume optimal interpolation method (or a typical "good" method which is commonly used).  Edit Jan 23, 2020 to include some clarification: What is of in view is the true color resolution and also how 1 / sqrt(2) is obtained as the number.

Color digital cameras are typically implemented by putting a color filter array (CFA) like a Bayer filter, plus an infrared cut filter, in front of a sensor that is sensitive to light frequencies spanning the full visible spectrum plus some range to either side of it.  The filters have two degradative effects:   They exclude light from reaching the sensor.  (E.g., a "green" sensor pixel may only receive photons that are within the range 500-570nm.  Most others are rejected.) Resolution is lost to "mosaic" effects.  (E.g., a green image component is only seen by half of the pixels in a Bayer filter.)   How are these losses quantified, and what is their typical magnitude in practice?


Disclaimer: I have no formal electronics training.   I am reading this book:   Here's the paragraph from that book that's got me confused:     The Raspberry Pi documentation allows up to 2.5 A for the Pi's   power supply, in case you don't want to use a powered USB hub. For   this cookbook, we will start with a powered USB hub but work toward   low-power and low-profile solutions.   I was under the impression that, from an abundant supply of amps, a device will draw only the amps it needs.  But the first sentence above implies that you should not connect a power source to the Zero board that is more than 2.5 amps.  Can you please set me straight?

Power supplies are available in a wide range of voltage and current ratings.  If I have a device that has specific voltage and current ratings, how do those relate to the power ratings I need to specify?  What if I don't know the device's specs, but am replacing a previous power supply with particular ratings?  Is it OK to go lower voltage, or should it always be higher?  What about current?  I don't want a 10 A supply to damage my 1 A device.


Java Edition:   During my entire time playing Minecraft from a TelePad (tablet which is connected with a telephone) from my history of phones, I always had one complaint that I got irritated of. I was never able to listen to the music in discs. Unlike Java, there is only 1 control for volume. I was able to hear almost everything. Block breaks, damage taking, movements, and even mob sounds, except background music or disc music. However, things were a bit different when I got the PewDiePie Texture Pack (Mod?) in where a certain bit of it is changing the songs from the discs to songs from PewDiePie. I eventually was actually able to listen to these discs, but not original songs, which really saddens me. I was trying to find ways why this is so. It also looks weird seeing parrots dancing with no music. Are there ways I can fix this?

I have some music discs, but every time I put it in a jukebox I can't hear it. It says it's playing, my friend (on PS4) says he can hear it, but I don't. All other audio is fine, I can hear the game audio fine, even if I have a world that's only me: it still doesn't produce jukebox sounds. It visually shows that it's playing (the notes come out of the jukebox) but there is no music. I play on Pocket Edition. Can someone help me resolve this issue?


Is there any fast way to get the remainders of the division of large numbers? Like$-$ $$\frac{77^{200}}{54}$$

How do I efficiently compute $a^b\bmod c$:  When $b$ is huge, for instance $5^{844325}\bmod 21$? When $b$ is less than $c$ but it would still be a lot of work to multiply $a$ by itself $b$ times, for instance $5^{69}\bmod 101$? When $(a,c)\ne1$, for instance $6^{103}\bmod 14$?  Are there any other tricks for evaluating exponents in modular arithmetic?  This is being asked in an effort to cut down on duplicates, see  and .


Given a Kähler manifold $(M,g)$ and the differential $\omega=\sqrt{-1} g_{\alpha\bar{\beta}}dz^{\alpha}\wedge dz^{\bar{\beta}}$, how to arrive the following results:  $\omega$ is closed, i.e. $d\omega=0$ iff in terms of components of $g$, $$\frac{\partial g_{\alpha\bar{\beta}}}{\partial z^{\gamma}}=\frac{\partial g_{\gamma\bar{\beta}}}{\partial z^{\alpha}}.$$  I also wonder if the following property is true in complex manifold: $dz^{i}\wedge dz^{j}=-dz^{j}\wedge dz^{i}$, $dz^{i}\wedge d\bar{z}^{j}=-d\bar{z}^{j}\wedge dz^{i}$ and $d\bar{z}^{i}\wedge d\bar{z}^{j}=-d\bar{z}^{j}\wedge d\bar{z}^{i}$. The above questions seem to be easy but it take me a lot of time without correct derivations and answers. Could someone give detailed derivations and answer to the above problems?

Let $(M,\omega)$ be a Kähler manifold. Why is the Kähler condition $$d \omega = 0$$ equivalent to $$\partial_kg_{i\bar j} = \partial_ ig_{k\bar j}$$ for all $i, j, k$?  I am looking for a reference.


I enclose more info, although I'm a bit of a newbie. Have seen several workarounds for 18.04 but when I installed it I had no wifi or touchpad. This is done with sudo lshw -c network  *-network UNCLAIMED        description: Network controller        product: RTL8821CE 802.11ac PCIe Wireless Network Adapter        vendor: Realtek Semiconductor Co., Ltd.        physical id: 0        bus info: pci@0000:01:00.0        version: 00        width: 64 bits        clock: 33MHz        capabilities: pm msi pciexpress cap_list        configuration: latency=0        resources: ioport:2000(size=256) memory:f0c00000-f0c0ffff   *-network        description: Ethernet interface        product: RTL810xE PCI Express Fast Ethernet controller        vendor: Realtek Semiconductor Co., Ltd.        physical id: 0        bus info: pci@0000:02:00.0        logical name: enp2s0        version: 07        serial: e8:6a:64:54:fb:a8        size: 100Mbit/s        capacity: 100Mbit/s        width: 64 bits        clock: 33MHz        capabilities: pm msi pciexpress msix vpd bus_master cap_list ethernet physical tp mii 10bt 10bt-fd 100bt 100bt-fd autonegotiation        configuration: autonegotiation=on broadcast=yes driver=r8169 duplex=full firmware=rtl8106e-1_0.0.1 06/29/12 ip=192.168.0.170 latency=0 link=yes multicast=yes port=MII speed=100Mbit/s        resources: irq:33 ioport:1000(size=256) memory:f0b00000-f0b00fff memory:f0800000-f0803fff

I'm trying to install drivers for my Wifi on my HP All-in-one desktop. I've been told to show the output of the command "sudo lshw -C network" so here it is:  *-network description: Ethernet interface product: RTL8111/8168/8411 PCI Express Gigabit Ethernet Controller vendor: Realtek Semiconductor Co., Ltd physical id: 0 bus info: pci@0000:01:00.0 logical name: enp1s0 version: 15 serial: 48:ba:4e:5c:06:5f size: 100Mbit/s capacity: 1Gbit/s width: 64 bits clock: 33MHz capabilities: pm msi pciexpress msix bus_master cap_list ethernet physical tp mii 10bt 10bt-fd 100bt 100bt-fd 1000bt 1000bt-fd autonegotiation configuration: autonegotiation=on broadcast=yes driver=r8169 driverversion=2.3LK-NAPI duplex=full firmware=rtl8168h-2_0.0.2 02/26/15 ip=192.168.1.21 latency=0 link=yes multicast=yes port=MII speed=100Mbit/s resources: ire:31 import:e000(size=256) memory: fea04000-fea04fff memory:fea00000-fea03fff  *-network UNCLAIMED description: Network controller product: Realtek Semiconductor Co., Ltd. vendor: Realtek Semiconductor Co., Ltd. physical id: 0 bus info: pci@0000:02:00.0 version: 00 width: 64 bits clock: 33MHz capabilities: pm msi pciexpress cap_list configuration: latency=0 resources: import:d000(size=256) memory:fe900000-fe90ffff   Output from "lspci -nnk | grep -A2 0280":  02:00.0 Network controller [0280]: Realtek Semiconductor Co., Ltd. RTL8821CE 802.11ac PCIe Wireless Network Adapter [10ec:c821] Subsystem: Hewlett-Packard Company RTL8821CE 802.11ac PCIe Wireless Network Adapter [103c:831a] 03:00.0 Unassigned class [ff00]: Realtek Semiconductor Co., Ltd. RTS5229 PCI Express Card Reader [10ec:5229] (rev 01)


I know this question has been asked a million times, but none of the things I've tried from other answers have worked. I've got a Caicos HDMI Audio [Radeon HD 6400 Series] audio device and I've installed "PulseAudio Volume Control" after reading this thread  and I can see "Radeon HD 6400" listed in the output devices and see the volume meter moving when I try to playback audio, but nothing comes through the speakers. aplay -l outputs:    **** List of PLAYBACK Hardware Devices **** card 0: SB [HDA ATI SB], device 0: VT1708S Analog [VT1708S Analog]   Subdevices: 1/1   Subdevice #0: subdevice #0 card 0: SB [HDA ATI SB], device 3: VT1708S Digital [VT1708S Digital]   Subdevices: 1/1   Subdevice #0: subdevice #0 card 1: Generic [HD-Audio Generic], device 3: HDMI 0 [HDMI 0]   Subdevices: 1/1   Subdevice #0: subdevice #0       I can also see the "output bar" moving as if it were playing audio, but still no sound from the speakers...  Any ideas?    Thanks in advance, Dan

My PC has a build-in VT1828S chip. The connection between PC and monitor (which has built-in speakers) is through an HDMI cable.  Audio preferences shows 2 devices for audio output: analog stereo and RS880 Audio Device [Radeon HD 4200] digital stereo (HDMI).  When I plug a headphone in the rear jack and I choose the former device, everything works. When I choose the latter device, instead, no sound is heard, and video playback is too fast. It is as if video frames want to synchronise with the audio timing, but the audio timing information is wrong.  HDMI audio worked perfectly with Ubuntu 11.04, but stopped after 11.10 upgrade.


Prove: There exists $a \in \mathbb{Q}$ and $b \in \mathbb{R}\smallsetminus \mathbb{Q}$ such that $a^b \in \mathbb{R} \smallsetminus \mathbb{Q}$.  I've tried using $\log_23$, $\sqrt 2$, and $\frac{1}{\sqrt 2}$ for the irrational number, but couldn't find a way to prove $a^b$ was irrational.  Is there a way to prove this without using Gelfond–Schneider theorem?

Is $2^\sqrt{2}$ irrational? Is it transcendental?


Does it make sense to follow an adjective phrase such as "however difficult" with the modal auxiliaries "may/might"? Isn't it a bit pleonastic, since "however" already contains the idea of either uncertainty, or irrelevance?  "However wealthy he was / However wealthy he might have been, she would not have married him if she had not been in love with him."  Does "he was" imply that his wealth was certain but irrelevant, and "he might have been", that it is/was a matter for conjecture and irrelevant, anyway?

Non-native speakers often get confused about what the various tenses  and aspects mean in English. With input from some of the folk here I've put together a diagram that I hope will provide some clarity on the matter.  I offer it as the first answer to this question. Consider it a living document. Input is welcome, and good suggestions will be  incorporated into the diagram.    Nota bene: What this is not is a discussion of whether there are  more than two tenses in English. , to which this question is not intended to supply arguments one way or the other.  Here, the aim is to provide an overview of what constructions English-speaking people use for conveying information about actions referring to past, present, and future, and to provide it first and foremost to precisely the people who are likely to use "tense" as a catch-all term in their search, rather than to linguists who know better.  Breaking News There is now an excellent ELU blog article titled  . It is highly recommended reading.


I have installed dropbox on ubuntu 16.04.  I have had it run before.  Now I have restarted and it is not running.   How do I start it manually, as I don't want it to automatically start on startup?

Since a while, 2 weeks, Dropbox does not startup anymore on my laptop running Ubuntu 12.04 LTS with GNOME shell.  When I run dropbox start -i in the console I get the following output.    Starting Dropbox...Traceback (most recent call last):   File "/usr/bin/dropbox", line 1387, in <module>     ret = main(sys.argv)   File "/usr/bin/dropbox", line 1376, in main     result = commands[argv[i]](argv[i+1:])   File "/usr/bin/dropbox", line 1247, in start     if not start_dropbox():   File "/usr/bin/dropbox", line 731, in start_dropbox     stderr=sys.stderr, stdout=f, close_fds=True)   File "/usr/lib/python2.7/subprocess.py", line 679, in __init__     errread, errwrite)   File "/usr/lib/python2.7/subprocess.py", line 1249, in _execute_child     raise child_exception   OSError: [Errno 8] Exec format error   I already removed Dropbox and reinstalled it. What should I do to fix this?


I have a 24V supply and need to drop the supply voltage to 19V to power a TV set.  The plug pack that powers the TV states the output as 19V and the current at 2.1A  I could use a resistor to drop the voltage but it would need to have a high power rating. Can anyone suggest a cct using easily obtained components to solve this problem?

I have been looking around for an easy way to convert 12V to 5V. I have seen some people saying that a simple resistor is all that is needed.  $$ Volts = Ohms \cdot Amps $$ $$ Amps  = \frac{Volts}{Ohms} $$ $$Ohms  = \frac{Volts}{Amps}$$  So applying a resistor will diminish the voltage of the circuit. That should mean that an appropriately sized resistor could simply be placed in the path of a 12V circuit, converting it to 5v.   If this is the case how would one reduce amps? Would series vs parallel make a difference in this area?   I have seen designs that include a regulator IC and some capacitors, but if a simple resistor/fuse/diode setup will do the trick, I would really prefer that.


When using conjunctions in a question to connect two sentences, should I add a comma before the conjunction? For example,  Why did you leave me to be like this ,and disappear without a single trace?  Or,  Why did you leave me to be like this and disappear without a single trace?

I often see people on the Internet using a comma before and in many cases (not adversative cases). Is it ok? In my language it is stricly prohibited to use a comma before an and except for adversative cases or when an apposition is in the front of that and. Examples (which I consider not ok):  He is a great player, and he prefers to play Counter-Strike. John joined the Army, and George joined the Marines.  What I consider exceptions:  Yes, and what is the problem? I called John, my brother, and now I’m speaking with him.


Show that if $f:\mathbb{R^{2}} \Rightarrow \mathbb{R}$ is a harmonic non-constant function, then it is surjective. I know it can be proved using Liouville's theorem, but i need to prove it without using it.

Let $u:\mathbb R^2 \to \mathbb R$ be a non-surjective harmonic function.  $(i)$ Show that $u$ is bounded from below or from above.  $(ii)$ Prove that $u$ is constant (and therefore any harmonic function is constant or surjective)  I know how to prove $(i) \implies (ii)$:  Suppose $|u|\leq B$, by hypothesis, there exists an entire function $f$ such that $f(x+iy)=u(x,y)+iv(x,y)$. If I consider $e^{f(z)}$, then $e^{f(z)}$ is an entire function and $$|e^{f(z)}|=|e^{u+iv}|$$ $$=e^u|e^{iv}|$$ $$\leq e^B.1$$ $$=c \in \mathbb R_{\geq 0}$$  This proves $e^{f(z)}$ is bounded so, by Liouville's theorem, $e^{f(z)}$ is constant. In this exercise  it is proven that $e^{f(z)}$ constant $\implies$ $f(z)$ constant.  I am having problems with the first part ($(i)$) of the exercise. Suppose $u$ is not surjective, then there exists $u_0 \in \mathbb R$ such that $u(x,y) \neq u_0$ for all $(x,y) \in \mathbb R^2$. I have no idea how to deduce $u$ is not bounded from this hypothesis, I would appreciate any hints.


Recently I got some money in my Apple ID and a few years ago I made a rescue email ( which I forgot how to enter ) and put some security questions I forgot how to awnser and I cannot buy apps ,music or movies because I need to fill in the security questions ! If I don't find an awnser on here, I will call Apple customers support.

I have an old Apple ID that I've lost access to because I deleted the email address it was tied to and I can't remember the security answers to anymore. I have some purchases tied to it, but the credit card info has been long removed -- it'd be expired by now, anyway. I called Apple Security, but was unable to regain access. Still, I'm wondering if anyone has been in a similar situation and how they went about recovering their account.


I'm trying to find if there is some solutions for collect data from users via some easy form (not google forms, something more powerful)?   I heard about arcgis collector, but you have to log in (so not everyone can submit a form) and it's mostly for organisation rather than for a large public..  Is it possible to collect this data not by manual writing input from users, but by simple click on a map joined to the form?

What  software is available to do mobile data collection, with GPS positioning.  Map display not required. I'm looking across the board (platform wise).  I'm already aware of...              Any others you're aware of?


When I try to take a picture using a slow shutter speed in daylight it is overexposed. How can I change the settings so it isn't overexposed?

Can anyone offer any tips on achieving long exposures (with the intention of blurring water, clouds etc)?


For a Ubuntu Studio beginner , how do you UPDATE an already existing Bitwig Studio-8 track DAW after having recently downloaded the update files (Bitwig Studio 3.2.8 deb) from the Bitwig Studio DAW ?

How do I install a .deb file via the command line?


I'm trying to figure out how best to stop Windows 10 from helping itself to updates. Firstly, I have a metered connection to the internet, and one that is of inconsistent speed. Secondly, I have an ideological objection to Microsoft installing its software without my permission (I have been burned by this before).  I'm aware that there is a setting for metered connections that delays downloads of some updates, but that doesn't prevent the others from being downloaded.  I've also found , but it doesn't seem to block updates in general, rather just blacklists certain updates that have already come out, and that your computer may or may not have already automatically downloaded and installed already.  I understand that Microsoft has no intention of returning to the days when you could see a list of updates, screen them, then downloading them when you have data to spare. But, is there any way that I can stop Windows from updating at all, for extended periods of time, then re-enable updating once I have the data?  Is there, maybe, a nice lightweight firewall that could block Windows Update?  EDIT: I have enabled the "defer upgrades" option, as suggested by the first answerer of the question I'm supposedly duplicating, but as Windows informs me, it will still help itself to security updates. I'm looking for a way to perform a blanket block on all updates until I want to install them, even if it means whitelisting every program that I want to use the internet. Does anyone here know how I could go about this?

We've upgraded some machines to Windows 10 and realized there were some updates which updated as required. However, I realized there was no option available to stop the download similar to that on Windows 7 and 8.1. The only way I could stop the download was to stop the Windows Update service.  My question is does anyone know of a way to stop auto updates or is stopping the service is the only solution?


I need help with a problem in Axler's Linear Algebra text. Any hint would be great.     Let $V$ be a vector space over $\mathbb{C}$ of dimension $n$, and $T: V\to V.$ If $$\dim \ker(T^{n-2}) \neq \dim \ker(T^{n-1}),$$ then prove that $T$ has at most two distinct eigenvalues.

The question is from Axler's Linear Algebra text. The $\mathcal{L}(V)$ stands for the space of linear operators on the vector space $V$.          Suppose that V is a complex vector space with dim $V=n$ and $T \in \mathcal{L}(V)$ is such that     $$\text{null} \ T^{n-2} \neq \text{null} \ T^{n-1}  $$     Prove that $T$ has at most two distinct eigenvalues.      I fist thought of solving this by contradiction. That is, I thought, suppose there were three distinct eigenvalues. Then, there would be an equation like  $$(x-\lambda_1I)^{d_1}(x-\lambda_2I)^{d_2}(x-\lambda_3I)^{d_3} $$ where the $d_i$'s are positive integers that sum to dim $V$. Call this polynomial $q(x)$ the characteristic poly. Thus, by Cayley's theorem, $$q(T)=(T-\lambda_1I)^{d_1}(T-\lambda_2I)^{d_2}(T-\lambda_3I)^{d_3}=0 $$ Then multiplying out and setting dim $V = d_1+d_2+d_3 = n$, I could then get a poly with the various powers of $T$ (this is a little tricky to write down). In particular, I wanted to see the powers $n-2$ and $n-1$. I thought, ok, so now, rewrite the poly in terms of each of these and using the fact that $\text{null} \ T^{n-2} \neq \text{null} \ T^{n-1}$ you get some vector $v \in V$ such that, $$T^{n-1}v = (\text{poly}_1)v = 0 $$  but  $$T^{n-2}v = (\text{poly}_2)v = k \neq 0 $$ I can think of some interesting things about $(\text{poly})_1$ and $(\text{poly})_2$, in particular, each has the monic term $T^n$. At this point, I'm not sure any of this helped.  Well, anyways, I'm sure someone has a much better approach! Thanks in advance to anyone who read this.


I have tried double checking for updates and updating the ppa via the terminal. The terminal outputs this, at the end.  E: Could not get lock /var/lib/dpkg/lock - open (11: Resource temporarily unavailable) E: Unable to lock the administration directory (/var/lib/dpkg/), is another process using it?   Any ideas? Thank you.

I get this error when trying to use apt-get:  E: Could not get lock /var/lib/dpkg/lock - open (11 Resource temporarily unavailable) E: Unable to lock the administration directory (/var/lib/dpkg/) is another process using it?     How can I fix this?


I recently had a session where the party was on board a boat (Smugglers) with a crew size of 40 which got into a fight with a boat (Royal Marines) with a crew size of 60.   Obviously I didn't put the whole crew into combat, I limited it to 10 Smugglers and 10 Marines (plus the captain of each boat).  Including the party, this meant there were 26 people on the initiative sheet, 22 of which were NPCs under my control fighting against each other. This meant that most of the fight was spent with the party watching me playing with myself.   Obviously this is unacceptable.  What would be a better way to deal with this? My job is to make the players have fun and not sitting around bored while I figuratively jerk off, but I also want to impress upon them the scale of a large battle.  I am willing to accept any and all suggestions, no matter how crazy (including incorporating other game systems).

I'll be rather specific:  Imagine you have five lv7 characters (in DnD3.5), a bunch of their followers (skeletons raised by their priestess and whatnot), and they're facing about the same number of opponents who pose a balanced (and, let's say, quite matching) challenge to the group.  In what ways can you speed up / sum up and get the result of the confrontation? The story would benefit a great deal from omitting or at least speeding really up the IRL hours long dice-rolling. (Yes, keeping track of which friendly skeleton hit which opposing skeleton is truly tedious, yet their presence in the story is both inevitable and good.)  (Side-question: Is there maybe a free app online that can intelligently play out such a skirmish?)  Answers relying on mechanics from, and/or usable in other d20 products are welcome.


I have written this line to replace + and = with space. But it returns an error stating     Quantifier follows nothing in regex   $element= ~ s/+/ /g; $element= ~ s/=/ /g;   Is this correct? How do I combine both conditions in one?

I am tired of always trying to guess, if I should escape special characters like '()[]{}|' etc. when using many implementations of regexps.  It is different with, for example, Python, sed, grep, awk, Perl, rename, Apache, find and so on. Is there any rule set which tells when I should, and when I should not, escape special characters? Does it depend on the regexp type, like PCRE, POSIX or extended regexps?


Can I publish SharePoint Provider Hosted app to office store?  I can't publish autohosted app to office store

Auto-hosted apps are not supported by Microsoft from next month, June 2014 onwards, Microsoft is recommending auto hosted apps to be converted to provider hosted apps. Publishing a SharePoint hosted app is relatively simpler as it is web scoped and all components are included in .app package.  What are the steps involved in publishing provider hosted apps to SharePoint store/Office store/App marketplace?