I am currently trying to install wine and previously have failed to install VLC on Ubuntu 17.10. I have tried almost all the solutions available on other forums.  $ sudo apt-get install vlc     Reading package lists... Done     Building dependency tree            Reading state information... Done     You might want to run 'apt --fix-broken install' to correct these.     The following packages have unmet dependencies:      libvlc5 : Depends: libvlccore9 (>= 4.0.0~rc1~~git20180102+r73456+113~ubuntu17.10.1~) but it is not going to be installed      vlc : Depends: vlc-bin (= 4.0.0~rc1~~git20180123+r73755+120~ubuntu17.10.1) but it is not going to be installed            Depends: vlc-plugin-base (= 4.0.0~rc1~~git20180123+r73755+120~ubuntu17.10.1) but 4.0.0~rc1~~git20180122+r73743+120~ubuntu17.10.1 is to be installed            Depends: vlc-plugin-qt (= 4.0.0~rc1~~git20180123+r73755+120~ubuntu17.10.1) but 4.0.0~rc1~~git20180122+r73743+120~ubuntu17.10.1 is to be installed            Depends: vlc-plugin-video-output (= 4.0.0~rc1~~git20180123+r73755+120~ubuntu17.10.1) but 4.0.0~rc1~~git20180122+r73743+120~ubuntu17.10.1 is to be installed            Recommends: vlc-l10n (= 4.0.0~rc1~~git20180123+r73755+120~ubuntu17.10.1) but 4.0.0~rc1~~git20180102+r73456+113~ubuntu17.10.1 is to be installed            Recommends: vlc-plugin-notify (= 4.0.0~rc1~~git20180123+r73755+120~ubuntu17.10.1) but 4.0.0~rc1~~git20180122+r73743+120~ubuntu17.10.1 is to be installed            Recommends: vlc-plugin-samba (= 4.0.0~rc1~~git20180123+r73755+120~ubuntu17.10.1) but 4.0.0~rc1~~git20180122+r73743+120~ubuntu17.10.1 is to be installed            Recommends: vlc-plugin-skins2 (= 4.0.0~rc1~~git20180123+r73755+120~ubuntu17.10.1) but 4.0.0~rc1~~git20180122+r73743+120~ubuntu17.10.1 is to be installed            Recommends: vlc-plugin-video-splitter (= 4.0.0~rc1~~git20180123+r73755+120~ubuntu17.10.1) but 4.0.0~rc1~~git20180122+r73743+120~ubuntu17.10.1 is to be installed            Recommends: vlc-plugin-visualization (= 4.0.0~rc1~~git20180123+r73755+120~ubuntu17.10.1) but 4.0.0~rc1~~git20180122+r73743+120~ubuntu17.10.1 is to be installed      vlc-plugin-base : Depends: libvlccore9 (>= 4.0.0~rc1~~git20180122+r73743+120~ubuntu17.10.1) but it is not going to be installed                        Depends: vlc-plugin-abi-4-0-0      vlc-plugin-notify : Depends: libvlccore9 (>= 4.0.0~rc1~~git20180122+r73743+120~ubuntu17.10.1) but it is not going to be installed                          Depends: vlc-plugin-abi-4-0-0      vlc-plugin-qt : Depends: libvlccore9 (>= 4.0.0~rc1~~git20180122+r73743+120~ubuntu17.10.1) but it is not going to be installed                      Depends: vlc-plugin-abi-4-0-0                      Recommends: vlc-bin but it is not going to be installed      vlc-plugin-samba : Depends: libvlccore9 (>= 4.0.0~rc1~~git20180122+r73743+120~ubuntu17.10.1) but it is not going to be installed                         Depends: vlc-plugin-abi-4-0-0      vlc-plugin-skins2 : Depends: libvlccore9 (>= 4.0.0~rc1~~git20180122+r73743+120~ubuntu17.10.1) but it is not going to be installed                          Depends: vlc-plugin-abi-4-0-0                          Recommends: vlc-bin but it is not going to be installed      vlc-plugin-video-output : Depends: libvlccore9 (>= 4.0.0~rc1~~git20180122+r73743+120~ubuntu17.10.1) but it is not going to be installed                                Depends: vlc-plugin-abi-4-0-0      vlc-plugin-video-splitter : Depends: libvlccore9 (>= 4.0.0~rc1~~git20180122+r73743+120~ubuntu17.10.1) but it is not going to be installed                                  Depends: vlc-plugin-abi-4-0-0      vlc-plugin-visualization : Depends: libvlccore9 (>= 4.0.0~rc1~~git20180122+r73743+120~ubuntu17.10.1) but it is not going to be installed                                 Depends: vlc-plugin-abi-4-0-0     E: Unmet dependencies. Try 'apt --fix-broken install' with no packages (or specify a solution).

Occasionally, when I'm installing stuff, I get an error like the following:  Some packages could not be installed. This may mean that you have requested an impossible situation or if you are using the unstable distribution that some required packages have not yet been created or been moved out of Incoming. The following information may help to resolve the situation:  The following packages have unmet dependencies:  package1 : Depends: package2 (>= 1.8) but 1.7.5-1ubuntu1 is to be installed E: Unable to correct problems, you have held broken packages.   How can I resolve this?


is there a way in Java to find if services like Windows Defender, IIS, Telnet are enabled? I am aware of the system class and you could always test ports with the socket class but I am looking for an easier solution. (If there is one)   Thanks for the help!

Here is the situation:  I have been called upon to work with InstallAnywhere 8, a Java-based installer IDE, of sorts, that allows starting and stopping of windows services, but has no built-in method to query their states.  Fortunately, it allows you to create custom actions in Java which can be called at any time during the installation process (by way of what I consider to be a rather convoluted API).    I just need something that will tell me if a specific service is started or stopped.  The IDE also allows calling batch scripts, so this is an option as well, although once the script is run, there is almost no way to verify that it succeeded, so I'm trying to avoid that.  Any suggestions or criticisms are welcome.


I want to get the PID of running program via the terminal. I searched here and in Google and I didn't find how I can do that. Which command will give me the PID of running process(es)?

I want to exit a process using the command line, but I can't recall the command to look up the process's ID.  Does anyone know it?


I have no photo ID issued by Government with me. Can I use an Affidavit with photo  duly sworn in before Notary can be A valid Photo ID. Is there  any  specific  language for such Affidavit.   Travel is domestic in India.

I am travelling from Delhi to Indore, a domestic flight. I forgot to take ID proof. Can I still fly?


So I've decided to choose the Arcane Trickster path for my Rogue. One interesting spell I saw was . The familiar can't attack but it can 'deliver' spells.     Finally, when you cast a spell with a range of touch, your familiar   can deliver the spell as if it had cast the spell. Your familiar must   be within 100 feet of you, and it must use its reaction to deliver the   spell when you cast it. If the spell requires an attack roll, you use   your attack modifier for the roll.   If I understand this correctly the spell is cast in the turn of the rogue and immediately delivered through the familiar as a reaction.   This means that the familiar has to be standing next to the enemy before its the rogue's turn and can only move away on its own turn. Leaving the enemy time for an attack. Since all familiars have a very low AC (13 max) and no HP to speak of, I do not understand how I can keep my familiar alive in combat.

The last paragraph of the Find Familiar spell contains the following:     ...when you cast a spell with a range of touch, your familiar can   deliver the spell as if it had cast the spell. Your familiar must be   within 100 feet of you, and it must use its reaction to deliver the   spell when you cast it.   Since the attack functions as a reaction for the familiar, it must already be within touch range of the target to deliver the spell, correct?  If a target is 30ft away, could a wizard ready a Shocking Grasp spell for "when my familiar is within touch range of that bugbear", allowing his owl to fly over, deliver the spell attack, and then fly away on its turn?   I assume his owl could not ready an action to fly to a goblin and back triggered upon "the wizard casts shocking grasp" since both would require a reaction, correct?


I started using Java with MySQL for the first time, so I don't know it well yet. I need help with this class. For some reason does the "if" make my programm crash. The class should scan the name and check if it's already used or not. When it's not used it should enter the name in the database.  I get the following error:  java.lang.NullPointerException     at Registration.register(Registration.java:38)  import java.sql.*; import java.util.Scanner;  public class Registration {     public static String name = null;     public static String name_db = null;     public static Connection connection = null;     public static Statement selectStmt = null;     public static Statement selectStmt2 = null;     private static Scanner in ;      public static void register() {          in = new Scanner(System. in );          System.out.println("Name:");         name = in .nextLine();          Connection connection = null;         Statement selectStmt = null;          try {             Class.forName("com.mysql.jdbc.Driver");             connection = DriverManager.getConnection(                 "jdbc:mysql://localhost:3306/java", "root", "");              selectStmt = connection.createStatement();              ResultSet rs = selectStmt.executeQuery("SELECT name FROM staffs where name = '" + name + "';");             if (rs.next()) {                  name_db = rs.getString("name");              }              if (name_db.equals(name)) {                 System.out.println("Name already exists.");             } else {                 System.out.println("Name is available.");                 selectStmt2 = connection.createStatement();                 selectStmt2.execute("INSERT INTO `java`.`staffs` (`id`, `name`) VALUES (NULL, '" + name + "');");             }            } catch (Exception e) {             e.printStackTrace();         } finally {             try {                 selectStmt.close();                 connection.close();             } catch (Exception e) {                 e.printStackTrace();             }         }      }  }

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?


So I have looked around some website, there is something interesting. The model is using 2 normals.  This normal is used to define the wrinkle of the cloth. Then there is this normal:  This normal is used to define the bump of the texture in tiny part of the texture. So this normal is used multiple times for each small parts of the texture. How can I achieve this is blender with PBR model?

I made a high poly model and then baked its textures onto a low poly model. Now I want to give another normal map's details to the model. How can this be done?


I am trying to prove that $$ \int\frac{1}{\sin^2(x)}dx = -\cot(x) + C $$ but I have difficulties, I don't know where to start, I can't substitute anything with $sin(x)$ because I don't have a $cos(x)$ to make it up for, I also know that: $$ \sin^2x = \frac{1 - \cos(2x)}{2} $$ so I basically have: $$ \int\frac{2}{1 - \cos(2x)}dx $$ and there I am stuck, how do I proceed?

According to my sheet of standard integrals,  $\int \csc^2x \, dx = -\cot x + C$.  I am interested in a proof for the integral of $\operatorname{cosec}^2x$ that does not require differentiating $\cot x$. (I already know how to prove it using differentiation, but am interested in how one would calculate it without differentiation.)


I am trying to figure out a way to do the following:  Given a $3 \times n$ grid, ($n \geq 2$) choose coloring by using $3$ colors (say, RGB), such that    any given column cannot have all grids of same color (i.e., no RRR in any single given column), a given row (which is of length $n$) cannot have all the same color.   Using the inclusion-exclusion principle and basic combinatorial principles seems like the right approach, but I am not sure of the pattern.

I have been reading about Combinatorial Material for a while now.  I also solved a few examples. However am stuck at this one.     Find the total number of ways a $3 \times n$ board can be painted using $3$ colors while making sure no cells of the same row or the same column have entirely the same color.  The answer must be computed modulo $10^9 + 7$.   I saw the solutions to $3 \times n$ using  colors but all these had the constraint that no adjacent cells were to have the same color. There's no such constraint here.  So am just not sure how to do this given the center row can have a bunch of options as well.  Thanks for any help.


Prove that if $\gcd(a,b)=1$ then $\gcd(a,bc) = \gcd(a,c)$.   Found many similar questions to this, but none the same. I've been trying to use Bezout's Lemma, but haven't figured it out.

For the integers $a,b,c$ show that $\gcd(a,bc)=\gcd(a,\gcd(a,b)\cdot c)$  Proof:  Let $u$ and $v$ be integers. Then $\gcd(a,b)=au+bv$. Then $c\cdot \gcd(a,b)=c\cdot(au+bv)=acu+bcv$ Let $x$ and $y$ be integers. Then $\gcd(a,\gcd(a,b)\cdot c)=ax+(acu+bcv)y=ax+acuy+bcvy=a(x+cuy)+(bc)(vy)$.  Let $d$ and $e$ be integers. Then $\gcd(a,bc)=ad+bce$.   Since $d$ and $e$ are integers let $d=x+cuy$ and $e=vy$. Hence $\gcd(a,bc)=\gcd(a,\gcd(a,b)\cdot c)$


I need to install ubuntu on my dell 3521 core i5  Ram 8 gb  Hd 1 terabyte  Vga amd 2 gb  Windows 7 ultimate Can it working fine or should i get an older version

I have a device on which I would like to install Ubuntu. How do I find out if Ubuntu will work on it?


I am doing a web app to filter recipes based on user's health information.  So if an admin adds a recipe of Friend egg(sunny side up).  Normally, based on how i cook my egg.  I would only need,  Chicken Egg (whole, commonly Large) Seasonings (mostly salt, say 1g)  How would i be able to make my own nutritional facts based on those 2 ingredients on my Sunny side up recipes?  I have a current Table named ingredient i use as a reference whenever inserting a recipe every ingredient of that recipes goes through this to reference its information.  The Columns are as follows:     Name - Description - Calories - Carbs - Fat   - Protein -      - Sodium -   Sugar - Group   Group refers to the food group, as for the above ingredient of egg, it should fall under poultry. Since chicken is poultry. Then salt, should be seasoning.  I'm not professional nor knowledgeable in terms of nutritional values.   I will greatly appreciate it if someone whose knowledgeable in the field could offer/show me  a simple way of making a nutritional facts.  My due is next week. I'm so confused and desperate.

I love to cook and experiment with recipes. While I'm aware that calories are not a perfect measure of what makes you gain weight and what doesn't, I would still love to have a rough idea of the energy values of the dishes I'm preparing, and ideally be able to fiddle with the ingredients just to see what happens to the calorie count.  How would I best approach this?   My vision is that of a tool that   lets you enter a recipe's ingredients and amounts, and can calculate an approximate calorie count for the most common ingredients ideally, lets you add other ingredients and their energy values?   I know for a fact there is software like this, but all the good products I've seen are for professional diet advisors, nutritional consultants and the like, and tend to be very expensive.   I guess the basic functionality could be achieved with an Excel sheet, but where to get high-quality nutritional data from? Are there industry-standard databases for this?   matches mine in the title, but seems to be more about the calorie differences between cooked and raw food, which is not my concern.


In several different OOP languages I can make a class that inherits from another class. Can I do a similar things with models in databases or is that strictly not allowed? Is it possible to make model inherit from another model? I ask this thinking about a products class.  Generally speaking each product will have  a name (nails, bolts, nuts), type (steel), some sort of size parameter and price. But could I maybe make an abstract model because different products may have different parameters that I care about, and then could I leave some columns as null?  Or do I need to declare all the different types of products and each product will have its own table?

I do not have much experience in table design. My goal is to create one or more product tables that meet the requirements below:   Support many kinds of products (TV, Phone, PC, ...). Each kind of product has a different set of parameters, like:   Phone will have Color, Size, Weight, OS... PC will have CPU, HDD, RAM...  The set of parameters must be dynamic. You can add or edit any parameter you like.   How can I meet these requirements without a separate table for each kind of product?


As I was studying this function, $f(x)=\sqrt[3]{1-x^3}$, I checked that the function is one-to-one, and so is invertible.  Then: $$y=\sqrt[3]{1-x^3}$$  $$y^3=1-x^3$$  $$y^3-1=-x^3$$  $$1-y^3=x^3$$  $$x=\sqrt[3]{1-y^3}$$ $$f^{-1}(y)=\sqrt[3]{1-y^3}$$  What kind of functions are inverse of itselfs? Thanks.

Just recently I read up something about involutions (functions $f: A \rightarrow A$ such that $f(f(x))=x$, for all $x$ in the domain of $f$), and was wondering how many (if there is a small set of general functions) such involutions exist for $A = \mathbb{R}$, or maybe $A = \mathbb{R} - S$, where S is some set of points that would make the involution work if they were left out of $A$. In general I'm interested in real functions that are involutions, continuous or otherwise.  There were some examples I found , but any more would be certainly very interesting!


The question: Let $f(x) = e^{-x}\sin(x)$. Calculate $f^{(2001)}(0)$. Note that in the question, $f^{(n)}(x)$. means the $n$-th derivative of $f$. I calculated the first six derivatives on zero and got: $f^{(0)}(0) = 0$. $f^{(1)}(0) = 1$. $f^{(2)}(0) = -2$. $f^{(3)}(0) = 2$. $f^{(4)}(0) = 0$. $f^{(5)}(0) = -4$. $f^{(6)}(0) = 8$. So, the pattern isn't pretty clear. Also, I thought that if $n$ is even, then: $f^{(n)}(x) = -e^{-x}\cos(x) - f(x) + f^{(1)}(x) - f^{(2)}(x) + ... + f^{(n-3)}(x) - f^{(n-2)}(x) - f^{(n-1)}(x)$. and $f^{(n - 1)}(x) = e^{-x}\cos(x) + f(x) - f^{(1)}(x) + f^{(2)}(x) + ... + f^{(n-4)}(x) - f^{(n-3)}(x) - f^{(n-2)}(x)$. So by substituting $f^{(n - 1)}(x)$ in the first equation, we get: $f^{(n)}(x) = -2(e^{-x}\cos(x) + f(x) - f^{(1)}(x) + f^{(2)}(x) + ... + f^{(n-4)}(x) - f^{(n-3)}(x))$ I tried to the same thing with $n$ being odd and tried to perform an induction to get a formula for the value of $f^{(n)}(x)$ but couldn't find a way to do so. Any ideas?

I've got this task I'm not able to solve. So i need to find the 100-th derivative of $$f(x)=e^{x}\cos(x)$$ where $x=\pi$.  I've tried using Leibniz's formula but it got me nowhere, induction doesn't seem to help either, so if you could just give me a hint, I'd be very grateful.  Many thanks!


My girlfriend will be starting college in the US in January. Is it possible for her to get a tourist visa so that she can be here more than 30 days before the start of her classes?

The F student visa allows me to enter the US up to 30 days before the program starts. For starting to set up things it is of my interest to arrive sooner than that. How hard is it to travel there beforehand with a tourist visa (waiver) and leave to, say Mexico, to then re enter on a proper date within the 30 days with the student visa? This seems easier than requesting for a status change inside the US from tourist to student..


I mistakenly create ~ in ~/source  sx@ubuntu:~/source$ pwd /home/sx/source sx@ubuntu:~/source$ ll total 440 drwxr-xr-x  3 sx sx   4096 2012-12-06 02:25 ~ drwxr-xr-x  4 sx sx   4096 2012-12-06 02:25 ./ drwxr-xr-x 47 sx sx   4096 2012-12-06 02:26 ../   I don't dare to delete it using command rm ~, because it may lead to deleting all my file in home dir.

I just noticed that I have a file called ~ in my ~-directory.  $ ls -la ~ ... -rw-r-----  1 x1 x1  733962240 Mar  1 17:55 ~ ...   Any idea how I can mv or rm it?


On Ubuntu 18.04 with GNOME triple shortcut combinations (like Ctrl+Alt+Shift+key) are always treated like Ctrl+Shift+key, so Alt is skipped. However, all double combinations (with Ctrl+Shift+, Ctrl+Alt+, Alt+Shift+) are processed properly in all windows.  This happens if the Alt+Shift combination is bound to switch keyboard layout (using gnome-tweaks, as described here )  Examples from Intellij IDEA:   Ctrl+Alt+Shift+S: expected Project Structure, but nothing happens (not sure what Ctrl+Shift+S makes by default) Ctrl+Alt+Shift+R: expected Resolve conflicts, actually: Replace in Path is called   Note:    opposite to the issue described in  and  this trouble appears as wrong shortcut is used (Alt key is ignored) rather than unexpected layout switching The problem happens in any window, not only Intellij IDEA The problem happens with any key, which includes Ctrl+Alt+Shift+   So, is it a bug that should be reported to Ubuntu / GNOME / Tweaks developers? Or am I misusing something?

Can I use Ctrl+Shift for changing languages? I can't set this hotkey for changing keyboard languages.  At this moment Alt+Shift switch languages, but I can't see this hotkey in keyboard hotkeys list or in   gsettings list-recursively  org.gnome.desktop.wm.keybindings | sort | more   output.


I guess the issue is already explained in the title.I want to remove GNOME 3.10 SHELL and all installed extensions in order to get clean ubuntu 14.04 but with all my software and private files saved. I've tried some commands found on the internet but i keep getting errors. What is the easiest way? For example to uninstall it in one or to terminal commands?

I'm having a bit of trouble getting gnome-shell to work ever since I installed an extension (I don't know which) on 11.10. So what I would like to know is: How can I completely uninstall EVERYTHING gnome-shell related (all the extensions, gnome-tweak-tool, etc.), everything - so I can start fresh and re-install 'em all one by one?  Thanks in advance.  EDIT: After a long and hard search (for me anyway) I found it:  sudo apt-get remove gnome-shell-extensions-*


Is there any bijection between closed unit interval and $R$?

Is there a bijection from a finite (closed) segment of the real line to $\mathbb{R}$? For example, is there a bijection from $[0,1]$ to $\Bbb{R}$?  If so, is there a straightforward example? If not, why?


I'm not very strong with RegEx but I am using a small regex expression and need assistance. The expression works, but I have been asked to turn the regex expression into a constant variable.  What's the best way for me to do this? Here is the code in question.    const storeNameDetails = (store) => {     const truncStoreNo = store.storeNo?.padStart(4, '0');     return STORE_LIST[truncStoreNo]?.replace(/ *\([^)]*\) */g, '');   };

Is there a way to use constants in JavaScript?  If not, what's the common practice for specifying variables that are used as constants?


We are noticing performance issues with one of our applications.  When the application issues begin the procedure cache size goes from 4.5GB to 0. The plans are then rebuilt and still the application is slow. If I update stats on a key table the issue goes away.  I'm just trying to understand how procedure cache may drop other than DBCC FREEPROCCACHE?  EDIT: Sorry this is SQL 2005 9.00.4226


Hello I've made a quick code to insert name into a database.  This is the class for database connection:  (I hide the passwords etc, basically i define them in the top)  class Database {     private $pdo;     private $query;     public function __construct()     {         try         {             $this->pdo = new PDO('mysql:host='.MYSQL_HOST.';dbname=oop', MYSQL_USER, MYSQL_PASSWORD);             $this->pdo->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);             echo 'Sucessfully connected to MySQL server!';         }         catch(PDOException $e)         {             echo $e->getMessage();         }     }      public function query($name)     {         $this->query = $this->pdo->prepare("INSERT INTO user (name) VALUES (:name)");         $this->query->bindValue(":name", $name);         $this->query->execute();         echo 'Sucessfully send!';     } }   This is the class that I basically use the queries and process them from :  class System {     private $Database;      public function __construct(Database $Database = null)     {         $this->Database = $Database;     }      public function insertName($name)     {         if ($this->db != null)         {             $this->db->query($name);         }     } }   This is config.php  include("system.class.php"); include("db.class.php");  $system = new System($Database); $db = new Database();   And this is index.php  <?php  include("config.php");  ?>  <html> <form action="" method="post"> <input type="text" name="name"> <input type="submit"> </form>  <?php      if (isset($_POST) && !empty($_POST['name']))     {         $Database->insertName($_POST['name']);         echo 'Scessfuly inserted!';     } ?> </html>   Problem:  When sending the data (after submiting the form) I get the following error:  Fatal error: Call to a member function insertName() on a non-object in C:\xampp\htdocs\oop\index.php on line 17  What did I do wrong? This is line 17:      $Database->insertName($_POST['name']);   How can I fix this and what is the problem?  Thnaks.  After changing it from $db to the actual name of the class I get this:  Call to undefined method Database::insertName() in C:\xampp\htdocs\oop\index.php on line 17  EDIT:  if (isset($_POST) && !empty($_POST['name'])) {     $system->insertName($_POST['name']);     echo 'Scessfuly inserted!'; }   class System {     private $Database;      public function __construct(Database $Database = null)     {         $this->Database = $Database;     }      public function insertName($name)     {         if ($this->Database != null)         {             $this->Database->query($name);         }     } }

So I'm refactoring my code to implement more OOP.  I set up a class to hold page attributes.  class PageAtrributes  {   private $db_connection;   private $page_title;      public function __construct($db_connection)      {         $this->db_connection = $db_connection;         $this->page_title = '';     }      public function get_page_title()     {         return $this->page_title;     }      public function set_page_title($page_title)     {         $this->page_title = $page_title;     } }   Later on I call the set_page_title() function like so  function page_properties($objPortal) {         $objPage->set_page_title($myrow['title']); }   When I do I receive the error message:     Call to a member function set_page_title() on a non-object   So what am I missing?


I want to know is there any theme available make it 'Ubuntu 10.04 desktop'  look like Windows 7 or Windows8 ?

I want to know is there any theme available make it Ubuntu look like Windows 7 ?


Does the rotating charged capacitor (both plates) produce magnetic field? and what about rotating both plates in opposite directions?

To what extent can a charged capacitor mounted on a moving platform (e.g. a rotating wheel) be considered an electric current generator? Electric current, after all, is nothing more than the transport of charge. Some extra detail:  Because a capacitor is a charge separation device, do the charges on the two plates effectively cancel to produce no net current?  If we ground one side of the capacitor, does the situation change?  If we rotate one plate and counter-rotate the other, do we succeed in producing net current?


I have some code like this    var minAmountPay =  <?php echo $this->chat['Current']['admin'] >= 1 ? 1 : $this->minAmountPay; ?>;   var userId = <?php echo $this->currentUserId?>;   I use ZF and I have a lot of javascript code in my action files. I want to create js-files for each action and do minifications of this files. But I can't create js-file because I have assigning php variable to javascript variable.  Maybe I need to use some javascript framework for this purposes?

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.


Is there an  software that can convert a graphical image (in PNG, GIF, TIFF, PDF... format) of a mathematical formula into the corresponding TeX markup?

Is there a tool for exporting equation images to TeX? Probably something related to OCR. I have a lot of image-equations in a word document that I'd like to convert to TeX.  Note that the equations are actually images, so no word2tex-like apps would help.


most of the apps have their executables in /usr/bin and other files also in the generally defines folders..  But i found some apps keep their executeables elsewhere...Now as in linux any file can be executeable the file can actually be placed anywhere..  But for achieving proper segrigation and stuff which locations  have been defined as the ones that should be preferably be used for various files of an app?  Is there any specification for it as such?

In Windows there’re perhaps only a couple of important folders (by important I mean important in my logical picture of the Windows file system) in the installation drive (in my case C:\). Namely Program Files and Windows. I simply stay away from Windows folder and the “add remove program files” is good enough to handle the program files folder of Windows. Of course there’s a folder named Users where the users (who are not admins) can access only their folders.  Thus there’s a clear picture at some level in my mind of the Windows file system. In Ubuntu, when I reach the location /, there’s a huge list of folders, most of which I have no clue as to what they contain. The /bin folder seems to be the equivalent of the Windows folder in windows. The /usr folder seems like it’s the equivalent of the Users folder in Windows. But even the /home folder looks like it can fit the bill.  Please understand that I do understand, that Ubuntu (Linux) has a different character than that of Windows, i.e., there need not be exact equivalent of Windows functions, in Ubuntu. All I am looking for is a bit more clearer picture of the Ubuntu file system.   This question is a part of a bigger question which I am splitting up to make it more answerable. The original question can be found here:


How to replace this statement with try/finally block?  using(MemoryStream ms = new MemoryStream()){}   Is this the correct approach?  MemoryStream ms = new MemoryStream(); try {    //code } finally {    ms.Dispose();                 }

I've got a bunch of properties which I am going to use read/write locks on. I can implement them either with a try finally or a using clause.  In the try finally I would acquire the lock before the try, and release in the finally. In the using clause, I would create a class which acquires the lock in its constructor, and releases in its Dispose method.  I'm using read/write locks in a lot of places, so I've been looking for ways that might be more concise than try finally. I'm interested in hearing some ideas on why one way may not be recommended, or why one might be better than another.  Method 1 (try finally):  static ReaderWriterLock rwlMyLock_m  = new ReaderWriterLock(); private DateTime dtMyDateTime_m public DateTime MyDateTime {     get     {         rwlMyLock_m .AcquireReaderLock(0);         try         {             return dtMyDateTime_m         }         finally         {             rwlMyLock_m .ReleaseReaderLock();         }     }     set     {         rwlMyLock_m .AcquireWriterLock(0);         try         {             dtMyDateTime_m = value;         }         finally         {             rwlMyLock_m .ReleaseWriterLock();         }     } }   Method 2:  static ReaderWriterLock rwlMyLock_m  = new ReaderWriterLock(); private DateTime dtMyDateTime_m public DateTime MyDateTime {     get     {         using (new ReadLock(rwlMyLock_m))         {             return dtMyDateTime_m;         }     }     set     {         using (new WriteLock(rwlMyLock_m))         {             dtMyDateTime_m = value;         }     } }  public class ReadLock : IDisposable {     private ReaderWriterLock rwl;     public ReadLock(ReaderWriterLock rwl)     {         this.rwl = rwl;         rwl.AcquireReaderLock(0);     }      public void Dispose()     {         rwl.ReleaseReaderLock();     } }  public class WriteLock : IDisposable {     private ReaderWriterLock rwl;     public WriteLock(ReaderWriterLock rwl)     {         this.rwl = rwl;         rwl.AcquireWriterLock(0);     }      public void Dispose()     {         rwl.ReleaseWriterLock();     } }


I just learned about Random Variables and Expected values and i tried solving the following question from my textbook  In an urn are N white balls. The balls are arbitrarily taken and at the same time a similar red ball is placed in the urn. So the number of balls in the urn has not changed. The same process is repeated until all N balls in the urn are red. Let X be the number of withdrawals made. Calculate the expected value of X  I'm having real struggles to Modell this problem correctly,  i tried via diffrent distribution concepts but non of them worked. Could someone give me some details on how to structure this problem

I recently came across this recurrence for the coupon collector problem:  $$\text{draws}(n) = \text{draws}(n-1) \cdot\dfrac{n}{n-1} + 1$$  where $\text{draws}(n)$ is the expected number of coupons to be drawn to get all $n$ unique coupons.  Why is this recurrence true? I would prefer an intuitive approach.


I received UK Visa refusal due to deposits I made in my account just before taking bank statement. Actually first 17 months from April 2018 until September 2019 I received salary in cash, 70125 SAR from which I saved liquid cash 12000 SAR which i deposited in bank. Since September 2019 my salary account was opened by the company, and this is the main refusal point mentioned by ECO. so all my savings which is hardly 10-12% of my net salary I deposited in bank. But I dint mention anything about it.   All my other documents stating my salary slip / traveling itinerary etc were accepted.   For new application : I got the letter from my employer that since when I was receiving my salary in cash.  I also obtained the exit and reentry visa (as its mandatory in KSA for expat) which clearly sates my traveling period and reentry in KSA.  This evidence is enough to prove my case? What should be my cover letter?  Secondly fro example I have submitted 10 documents in my previous application and they raised red flag for two. In new application I will provide same 10 documents with more evidence to prove my case. So is their any chance they raise red flag about some other document from the 10 which I submitted before and now as well.

I have applied recently for a general visitor visa to the UK to spend 10 days during Christmas with my British unmarried partner and it has been turned down.   The Entry Clearance Officer stated on his refusal notice the following:     I note that you have never previously travelled to the UK or any country with similar immigration requirements and you therefore do not have a history of travel and compliance to consider.      You have submitted an employment letter to confirm your occupation in KSA but I am required to also assess your personal, domestic and economic circumstances in determining whether you are genuine visitor travelling to the UK for the period and purpose you state.      You claim an income of SAR ........ per month which equal ........ GBP and from the evidence submitted this appears to be your sole source of income.   I note that this monthly income is reflected on your bank statements. However, the bank statement you have presented show a recent large deposit that are in excess of your stated income and inconsistent with the account history. You haven't provided evidence toward the origin of this recent deposit and in the absence of reasonable evidence I am not satisfied that these bank statements accurately reflect your personal circumstances.      In view of the above, I am not satisfied you have demonstrated that your circumstances are as you claim and therefore I am not satisfied that you're travelling to the UK for the period and purpose you stated. 41(i)and(ii).   Its true that I have deposited that sum of money right before I apply and it was a commission I received from work earlier this month.   So, could you please give me your advice on the above as I am planning to apply again soon. and how to avoid my application being refused again?


Whenever I ask'why does a proton attract electron?' People say that 'because they are oppositely charged'  But I want to know why do opposite Charges attract each other and tend to become neutralised?  The same is for all forces like gravity, intermolecular forces e.t.c. Is it because nature defined it to be so and just another question that no one can answer.

I know plus pushes another plus away, but why, really, do they do that? On the other hand, molecules of the same type are attracted to each other. I find that weird.  I do know some stuff about four universal forces. But why in general the general "rule" is that opposite charges pull each other?   Yes, I do realize this could be connected to very basic stuff that science is still trying to figure out, and can be traced to the Higgs,  but still, there must be something to tell.


What is the shape of a rain water drop and how it forms?  When tried to figure that out using surface tension, water drop becomes unnatural. Lower part has a smaller radius and upper part has a larger one.   For upper part, P1 - Patm = 2T/R1  For lower part, P2 - Patm = 2T/R2  But, P2 = P1 + hdg  So R1>R2  T = surface tension of water Patm = pressure of atmosphere  h = length of the water drop d = density of water R1 = radius of the upper part R2 = radius of the lower part g is gravitational acceleration   But we see inverse type of water drops in natural. What is the real physics behind this?

Raindrops are always pictured like this, people imagine they have this shape when they fall, but is this true? Doesn't this shape create too much drag? What shape do they really have? It would also be nice to know how is the actual shape formed regarding the flow of air.


I apologize if this question is already asked but i am not able to find the answer.  I have a list of elements. I wanted to group elements for every 4 elements in the array. Example:  my_list = ["A","B","C","D","E","F","G","H",....]  result = [{"A","B","C","D"},{"E","F","G","H"},....]

I have a list of arbitrary length, and I need to split it up into equal size chunks and operate on it. There are some obvious ways to do this, like keeping a counter and two lists, and when the second list fills up, add it to the first list and empty the second list for the next round of data, but this is potentially extremely expensive.  I was wondering if anyone had a good solution to this for lists of any length, e.g. using generators.  I was looking for something useful in itertools but I couldn't find anything obviously useful. Might've missed it, though.  Related question:


I am trying to get a standardised method to import plots from matplotlib into my LaTeX document, borrowing text formatting from the main document (so I want to avoid pure PDF). I am currently exporting the figure as  PGF. When I save the figure as a PGF the settings (linewidths, markersizes, annotation text sizes, etc.) do carry over properly, but the font is not inherited from the document. MWE: Create the figure in python: import matplotlib.pyplot as plt import numpy as np  plt.rcParams.update({'text.usetex': True})  x = np.random.random(10) y = np.random.random(10)  plt.figure() plt.plot(x, y, 'o') plt.xlabel('my xlabel') plt.ylabel('my ylabel')  plt.savefig('D:/_Current Work/fig.pgf')  LaTeX: \documentclass{article} \usepackage{pgf} \usepackage{pgfplots}  \renewcommand\familydefault{\sfdefault}  \begin{document}  \input{"D:/_Current Work/fig.pgf"}  \end{document}  The figure created will not change the font used in the tick labels and axes labels regardless of whether I include or omit the \renewcommand\familydefault{\sfdefault} to change the font to sans-serif. I've read many other posts on the forum about these two tools but it seems like this should work without any problems so I assume I am missing something basic. EDIT A few users suggested this question is a duplicate of . My problem seems to be the exact opposite of the question in the link: my math is being renderred according to the global math font correctly, but the normal text is not.

For creating the graphics for my thesis (function graphs, flow charts, line art sketches) I've chosen to use the sans serif font by  \renewcommand\familydefault{\sfdefault}    However when I use mathematical symbols like $p_{s}$, they are still typeset in roman font and that looks weird:    So I wonder:   how could I force mathematical expressions also be typeset in \sfdefault if I do, are there any negative sideeffects to expect (with greek signs or other special symbols?) OR should I typeset all "mathematical" graphs (axis labels etc.) in roman font, and only make the other graphics like flow charts and sketches with sans serif font?


I sent my files(pdf, docs...) from macbook to iphone but i did not open my files when received. And now i can not find my files anywhere. Is there anywhere or removed?

Where do AirDrop files go when I transfer them between an iPad, iPhone and iPod? I AirDropped some Google Docs from my iPad to my iPhone but nothing happened; where did my files go? The file was a list of tools.


I have an existing project, now i want to create a menu window (using WPF). I cannot seem to figure out how to add this to my existing project. How can i implement a "WPF-window" to a console app project?

I recently started a C# project (VS 2008) as a 'Console' project where I wrote a few libraries, test programs, etc.  Now I'd like to add a couple of WPF windows, but it looks like console project won't let me do that.  I'm coming from Java so this is a little strange.  How can I add a WPF form (which I will instantiate my self from my "main" class?


I need to numerate my document like:   1. Something   1.1. Something2     1.1.1. Something3    With the nested code:  \documentclass{article} \renewcommand{\labelenumii}{\theenumii} \renewcommand{\theenumii}{\theenumi.\arabic{enumii}.}  \begin{document} \begin{enumerate}   \item Something   \begin{enumerate}     \item Something2       \begin{enumerate}         \item Something3       \end{enumerate}   \end{enumerate} \end{enumerate} \end{document}   I achieve:   1. Something   1.1. Something2        i. Something3    Is there any way to do it the way I want it, the way above? How many times can I nest arabic numbers in that sense?   Thanks to all!  Some small edit: I managed to do it like this:  \begin{document} \begin{enumerate}   \item Something   \begin{enumerate}     \item Something2       \begin{enumerate}         \item[1.1.1] Something3       \end{enumerate}   \end{enumerate} \end{enumerate} \end{document}   But I consider it as a quite lame way.

I write homework assignments in LaTex and the assignments are always divided into subparts (i.e. Problem 1 is divided into 1.1, 1.2, 1.3, ...). Currently what I do is I have nested enumerations, but the numbering isn't exactly what I'd like. To number the subparts, I am currently using:  \renewcommand{\labelenumii}{\arabic{enumii}.}   However, this produces  1. 2. ...    and what I'd like it to be is   1.1 1.2 ...    Is there anyway to do this?


GameDev!  I would like to create a 2D overlay over a 3D world, using LWJGL (Java version of OpenGL), to show information to the player, for example, a chat box, health bar, selected cannonball type, etc.  Currently the code I have is this (Taken from several sources on the internet):  glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);         glEnable(GL_BLEND);         GL11.glMatrixMode(GL11.GL_PROJECTION);         GL11.glLoadIdentity();         glOrtho(0.0f, Display.getWidth(), Display.getHeight(), 0.0f, 0.0f, 1.0f);         GL11.glMatrixMode(GL11.GL_MODELVIEW);         GL11.glLoadIdentity();         glDisable(GL_DEPTH_TEST);         glDisable(GL_CULL_FACE);         glDisable(GL_TEXTURE_2D);         glDisable(GL_LIGHTING);         glDisable(GL_DEPTH_TEST);         glDisable(GL_CULL_FACE);         glDisable(GL_BLEND);         glDisable(GL_TEXTURE_2D);         glDisable(GL_LIGHTING);             glBegin(GL_QUADS);             glColor3f(1, 1, 1);             glVertex2f(0, 0);             glVertex2f(1, 1);             glVertex2f(1, 0);             glVertex2f(0, 1);             glEnd();         GL11.glMatrixMode(GL11.GL_MODELVIEW);         GL11.glLoadIdentity();             glPopMatrix();         glEnable(GL_DEPTH_TEST);         glEnable(GL_CULL_FACE);         glEnable(GL_BLEND);         glEnable(GL_TEXTURE_2D);         glEnable(GL_LIGHTING);              glEnable(GL_DEPTH_TEST);                 glEnable(GL_CULL_FACE);                 glEnable(GL_TEXTURE_2D);                 glEnable(GL_LIGHTING);              glDisable(GL_BLEND);                 GL11.glMatrixMode(GL11.GL_PROJECTION);                 GL11.glLoadIdentity(); // Reset The Projection Matrix                 GLU.gluPerspective(45.0f, ((float) Display.getWidth() / (float) Display.getHeight()), 0.1f, 5000.0f); // Calculate The Aspect Ratio Of The Window                  GL11.glMatrixMode(GL11.GL_MODELVIEW);                 glLoadIdentity();   However this does not show a 2D scene at all!  I would appreciate it if anybody could help me.  Thanks!

I'm at the stage in my game development where I need to make a HUD or GUI. I've never gotten to this part, so I don't know how its done. I tried rendering a simple quad at a fixed position on the screen, but there's a problem. To make my camera work with orthographic, I use this:  public void lookThrough() {     GL11.glMatrixMode(GL11.GL_PROJECTION);     GL11.glLoadIdentity();     GL11.glOrtho(position.x, position.x + Display.getDisplayMode().getWidth()/zoom, position.y + Display.getDisplayMode().getHeight()/zoom, position.y, -1, 1);     GL11.glMatrixMode(GL11.GL_MODELVIEW); }   I don't see how I would be able to make something fixed on the screen using this method? Any way around this? Thanks :)


I know it is not on the list of supported devices, but I would like to know if it is at all possible to install Ubuntu Touch on the Samsung Galaxy S3 MINI. I am tired of the bogged down interface of the Android installed by Samsung and would love to try out a new OS on my phone. I love the lay out of Ubuntu Touch and badly want to try it. Any help is much appreciated! (the phone is a AT&T phone)  Note: I am clearly stating that I know it is not on the list of supported devices. I want to know it the listed S3 process will work, or if there is any way to install even though it is not supported.  "I know it is not on the list of supported devices, but..." - The very first line in the question. Any help is appreciated!  This is not a duplicate because I know that this phone is not on the list that the page question will lead me too. I'm asking that if since the full version of this phone is on the list if it can be installed the same way on this phone. If not, is there any way I can try to manually install it?

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


According to the LSI 9207-8e  then it supports up to 1024 disks of 6Gb/s, which I don't quite understand, when it is only an 8 lane JBOD card.  In my case, I have an HP D6000 with 70 disks as JBOD, and have excellent read/write performance.   It would be temping to think that only 8 disks of the 1024 gets full bandwidth, but just can't be the case, or is it for some reason not an issue? If I bought the 12Gb/s LSI JBOD version, would I then get better performance when the disks are still 6Gb/s?

Please let me know if my question does not makes any sense as I am not sure if I am interpreting it correctly from my thoughts due to my lack of technical knowledge on this.   If I am using a motherboard which has a connection for a SFF-8087 to 4x cable such as this  connection.   I am still learning about SAS but was told to build a system from a potential employer utilizing these connections. However, I am just not sure I understand the concept on how the system will treat the SATA connections which are going into the SAS port via this cable.   Also what would be the advantage of doing it this way as opposed to just connecting the SATA drives directly into the SATA motherboard ports? I believe the built-in SAS connection may be an integrated RAID controller.   Although, yes I can just go ahead and connect all the cables that fit I would like to have a better grasp of what I am doing such as:   If a motherboard has SAS connections, should I automatically assume it has some type of RAID controller built-in or is this on a case by case basis? Do All RAID controllers have only SAS connections? Even though the SATA drives are connected via a SAS connection, are they still just treated as SATA drives or as SAS technology?


I know of an explanation that the Earth is a inertial frame of reference since it is rotating about its own axis, and since this is happening there is a centrifugal "force" or effect which counters the gravitational one. I know this is a fictitious force and I don't really find myself truly understanding anything if I have to use fictitious forces so I'm not satisfied with this explanation.  Also, I know of an explanation that observes this from a non-inertial frame of reference, saying that since gravity is the centripetal force in effect a part of it has to go on rotating a mass on a certain radius form its axis, therefore the "weight" part of the gravity slightly decreases. How is this happening?  If we assume a constant gravitational force on a constant mass on the surface of the Earth, then on the poles it is evident that the weight of the mass would be a consequence of purely the gravitational pull. However, on the equator the gravitational force itself is still the same, how is then the net acceleration decreased thus also the weight?

Many sources state that the Earth's gravity is stronger at the poles than the equator for two reasons:   The centrifugal "force" cancels out the gravitational force minimally, more so at the equator than at the poles. The poles are closer to the center due to the equatorial bulge, and thus have a stronger gravitational field.   I understood the first point, but not the second one. Shouldn't the gravitational force at the equator be greater as there is more mass pulling the body perpendicular to the tangent (since there is more mass aligned along this axis)?


One example of a manifold with boundary is said to be the $n$-dimensional disk, so $M:=\{x\in\mathbb{R}^n:||x||\le 1\}$. In order to show this, one has to show there are charts $h_i:U_i\to U_i^\prime\subseteq\mathbb{R}^n_-=\{(x_1,...,x_n)\in\mathbb{R}^n:x_1\le 0\}$ with the properties of an atlas for normal manifolds. So basically the charts have to homeomorphically map the manifold to open sets in the "half-plane". To verify the example of the disk, can't I just take the translation $h:M\to M-(1,0,...,0)\subseteq \mathbb{R}^n_-$ as an atlas consisting of just a single chart? Moreover for any bounded set in $\mathbb{R}^n$, can't I just translate it into $\mathbb{R}^n_-$ and get a manifold with boundary?

"Show that every closed ball in $\mathbb{R}^n$ is an $n$-dimensional manifold with boundary, as is the complement of every open ball. Assuming the theorem on the invariance of the boundary, show that the manifold boundary of each is equal to its topological boundary as a subset of $\mathbb{R}^n$, namely a sphere. Hint: for the unit ball in Rn, consider the map  $\pi \circ \sigma^{-1}: \mathbb{R}^n \rightarrow \mathbb{R}^n$, where $\sigma$ is the stereographic projection and $\pi$ is a projection from $\mathbb{R}^{n + 1}$ to $\mathbb{R}^n$ that omits some coordinate other than the last."  So, I've got (the first part, anyways) of the question done, but my technique was a little different than what Prof. Lee suggested: I considered the ball as infinitely many foliated spheres, mapped each one to a plane using the stereographic projection, and then put the last coordinate as a function of the distance from the north/south pole. However, my solution seemed to neatly avoid any use of $\pi$ as mentioned, and I'm curious if anyone knows how that solution runs.


MCQ Paper is mentioned below (Thanks to Erik) ;   \documentclass[addpoints,answers,10pt]{exam} \setlength\textheight{15cm} \setlength{\footskip}{8.5cm}  \providecommand{\myquestion}{% \question  Question text  \begin{choices} \choice First choice \choice Second choice \choice Third choice \choice Fourth choice \end{choices} \medskip } \begin{document} \begin{questions} \myquestion \myquestion \myquestion \myquestion \myquestion \myquestion \myquestion \myquestion \myquestion  \end{questions} \end{document}   I want to add heading "Space for rough work" and Horizontal Line as mentioned in the diagram below (Highlighted in RED color).     Kindly advise?

I've MCQ Paper created using \documentclass[addpoints,answers,10pt]{exam} ; here on very page I've to provide "Space for Rough Work". Height of "Space for Rough Work" is around 20% of page height. This height is constant on all pages . Kindly suggest, if there is any way to add constant height at the bottom of page reserved for Space for Rough work ?   I tried \setlength{\footskip}{200pt} ; but it's not working.


I understand that any natural number congruent to 2 or 4 (mod6) is even and that 3 is the only prime congruent to 3(mod6). Thus, any prime, p > 3, must be congruent to either 1 or 5 (mod 6). I just don't understand the reasoning behind why any natural number congruent to 2 or 4 (mod6) is even and that any natural number congruent to 3(mod6) is a multiple of 3. Could someone explain why this is true?

Can we prove that every prime larger than $3$ gives a remainder of $1$ or $5$ if divided by $6$ and if so, which formulas can be used while proving?


I was working on this code to take in a target String and search the linked list for the target and delete all instances of it. I feel like I have most of the logic down but I am getting a NullPointerException and was needing some help. here is the code:  public class LinkedStringLog implements StringLog {   private LLStringNode head;   private int numOfEntries;     public LinkedStringLog() {//constructor     head = null;     numOfEntries = 0;     }     public void delete(String target){//deletes all entries of target      LLStringNode current = head;     LLStringNode prev = head;      for (int i = 0; i < numOfEntries; i++) {         prev = current;         current = current.getNext();          if (target.equals(current.getValue())){             prev.setNext(current.getNext());             current.setNext(null);             numOfEntries--;          }     }   }

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 want to run vncserver on startup How I can do it in startup file directly or create a custom Command via alias if possible

How do I create a system-wide autostart file?  This would be on a cloud server running the desktop version of Maverick.  I logged in as root and created an autostart file using System/Preferences/StartupApplications but it ended up in /root/.config/autostart and did not execute (as far as I can tell) upon rebooting.  The autostart file is to invoke a bash script that invokes the VNC server.    I copied the .desktop autostart file from /root/.config/autostart to /etc/xdg/autostart and rebooted.  This did not seem to make a difference.  Edit As mentioned in a comment, the objective is to run my bash script which starts the VNC server upon boot; not upon a login.


I traverse an array of bytes in a Try...Catch block. Something like this:          Try             For Each curByte In bytes                'Do something with bytes.                 Next             Return encodedBytes         Catch e As Exception             'handle exception         End Try   Randomly, my program will crash with an unhandled exception on the Next statement in the code block above. The exception is a StackOverflow in mscorlib.dll "unable to evaluate expression".   Why is my exception handling not handling the exception? I'm not sure I know where to begin trying to address this error.

After hitting a few StackOverflowExceptions in .NET I noticed they completely bypass the unhandled exception handlers that .NET offers (Application.ThreadException / AppDomain.UnhandledException). This is very disturbing since we have critical cleanup code in those exception handlers.  Is there any way to overcome this?


I am attempting to read from a file in Java, and use the string I get as a condition in an if statement. I know the reader is correct (it works in other programs), but when I try to do something like  if(reader.getVariable() == "A") {     do x } else {     do y }   It will always do y, even though printing out the getVariable() method returns "A". Why is this?

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


How can I set the DPI of an image made with EEVEE? I want a 300DPI render for printing thanks

Is there a way to output for Print. I want to save in a higher DPI than the default 72dpi say 300dpi that's a good quality for printed pieces. I tried downloading an add-on but don't know if I am installing it correctly it isn't showing up but the bar in python is green. I'm using the 2.69 version of Blender. If no such feature exists what size have any of you found best for print quality. Thank you


If there is no oxygen in space, where the super dense singular object was suspended, then why did it explode because this reaction needs oxygen?

TV documentaries invariably show the Big Bang as an exploding ball of fire expanding outwards. Did the Big Bang really explode outwards from a point like this? If not, what did happen?


I can see the used disk quota on server is 81G for partition /dev/sda3 mounted to '/' as follows.  Filesystem      Size  Used Avail Use% Mounted on /dev/sda3       106G   81G   20G  81% / tmpfs           1.9G     0  1.9G   0% /dev/shm /dev/sda1       477M   52M  400M  12% /boot tmpfs           1.0G     0  1.0G   0% /var/lib/mysqltmp /usr/tmpDSK     4.0G  183M  3.6G   5% /tmp   But when Iam checking with the '/' directory by executing du -sh command it is taking only 17G of disk space, can any one advice where this remaining space is utilized, any advice ? Iam using CentOS release 6.7 (Final)

I have a SCSI disk in a server (hardware Raid 1), 32G, ext3 filesytem. df tells me that the disk is 100% full. If I delete 1G this is correctly shown.  However, if I run a du -h -x / then du tells me that only 12G are used (I use -x because of some Samba mounts).  So my question is not about subtle differences between the du and df commands but about how I can find out what causes this huge difference?  I rebooted the machine for a fsck that went w/out errors. Should I run badblocks? lsof shows me no open deleted files, lost+found is empty and there is no obvious warn/err/fail statement in the messages file.  Feel free to ask for further details of the setup.


I followed some instructions from  to connect to a VPN on startup, however, every few months something goes awry and I find myself not connected to the VPN. How can I kill the internet if it can't connect to the VPN?

I want to block all internet connections unless I'm connected to my OpenVPN. Now of course, I need to allow connection to the VPN server.  Can this be done, by allowing out/in traffic to/from the VPN server ip, but have a drop all rule afterwards with iptables?  I tried to solution proposed by @tachomi, but I don't have internet connection, when the iptables rules are set. iptables-save states:  # Generated by iptables-save v1.6.0 on Wed Feb  3 00:53:32 2016 *filter :INPUT DROP [247:40343] :FORWARD ACCEPT [0:0] :OUTPUT ACCEPT [153:25961] -A INPUT -s 127.0.0.1/32 -p tcp -j ACCEPT -A INPUT -s 127.0.0.1/32 -p tcp -j ACCEPT -A INPUT -s 127.0.0.1/32 -p udp -j ACCEPT -A INPUT -s 127.0.0.1/32 -p udp -j ACCEPT -A INPUT -s <VPN_SERVER_IP>/32 -p tcp -j ACCEPT -A INPUT -s <VPN_SERVER_IP>/32 -p udp -j ACCEPT -A OUTPUT -d <VPN_SERVER_IP>/32 -p tcp -j ACCEPT -A OUTPUT -d <VPN_SERVER_IP>/32 -p udp -j ACCEPT COMMIT # Completed on Wed Feb  3 00:53:32 2016


What equations so I can model a "bouncing particle"?  I've initially started with just $$f(x,y)=(x,\text{abs}(\sin(x)))$$  But I'm interested in doing gravity and speed changes and stuff. So how to proceed?  Some other equations perhaps?

I'm programming an animation of a bouncing ball, and I want it to be as realistic as possible.  I fully understand the physics while the ball is rising and falling: It accelerates downward at 9.8 meters/second/second.  But once it hits the ground, I'm lost. I know that it experiences some compression which translates it's velocity upward again, at which point gravity is again the only force acting on it. But I don't know how to model the compression and deflection of the ball hitting the ground.  (Also, I'm only dealing with strictly vertical linear velocity and acceleration. The ball isn't traveling horizontally or rotating at all. And I'm assuming negligible loss to air resistance.)  I know there are constants to deal with: how much the ball resists compression and how much energy is lost during the bounce, but I don't know how they are related.  Can anybody give me a one- or two-paragraph explanation and/or (a) formula(e) and/or point me to a resource where I can read more? (yes, I've already spent an hour or so googling it)  I'm happy to continue reading about it until I understand, I just don't know where to turn at this point.  Thanks in advance!


There is this lopsided power button symbol in the AppCode (XCode replacement) keymap.  Any long time Mac users know which button it refers to?

This tip just popped up in my phpStorm IDE (OS X):     The ⎋ key in any tool window moves the focus to the editor. ⇧⎋ moves   the focus to the editor and also hides the current (or last active)   tool window. The F12 key moves the focus from the editor to the last   focused tool window.   I've never seen that key symbol before and Google returned nothing.  Anybody know the meaning of this mysterious key?


I am a kid. I have a loose tooth where the part is off but the other part isn't. I can see my new tooth underneath. Should i just suck it up and push with my tongue?  It's a bottom left molar

My 5 year old is starting to have some teeth become loose. Specifically her lower two front teeth. I just noticed today that one of them is really loose. However, I don't know how loose it should be before pulling it out.  I'm also curious about how to pull them (or should I just let them fall out, which seems bad). My father pulled mine with pliers but I think my wife would freak out if I tried to do that.  So, how loose is lose enough and how to pull them out (technique, tools, etc.).


I wanted to adjust the size of my desktop background image, but could not see any options in Settings -> background for doing so. I came here and found these two questions:   and  . Both feature an image of Settings -> appearance with a number of options, and I have a vague memory that I had something like that once, but it is nowhere to be found now. These questions are 7 and 4 years old as of this writing. I did find something called 'Appearance' in the Ubuntu Store. Did this functionality get moved into that app?   I am no master of gimp, but I also tried using it to reduce the size of my image, and frankly, I can't even tell if Ubuntu accepted my 'set as background' command, because it still looks the same size. Are there any other options here?

Recently updated to 18.04.1 and now I cannot resize my background image from fill screen to center image.  How can I resize the image now that 18 doesnt have the quick resize feature?


I performed a PCA on some data related to habitat (different types of vegetation cover, soil water etc.), but there were some variables that I did not include in the PCA because they were not strongly correlated with any of the other variables. I selected the first three principal components from the PCA whose eigenvalues were above 1.  Now I want to run a multiple regression to analyse what variables will predict bird density. Is it valid to include my three principal components as well as the variables that I did not include in the PCA into this regression?

I did a principal component analysis, which resulted in 7 components that I am now using for a principal component regression on my independent variable.  However, I want to add 2 control variables, but these are not component scores, but "normal" variables (on a Likert scale, the same sort of variables my independent variables were).  Is that okay to do or do I have to make these into components as well? I have done the regression both with those two as variables and combined in a component and the results are practically the same.


Every TvP replay of mine that I check I always see that my enemy has perfect information on when my troops are leaving my base. I don't want to give my opponents this information and vs Zerg, I always make an effort to snipe all the Overlords that are on the map, but vs Protoss, I can't find any solution.  I tried to build Sensor Towers in the hope that it would detect them, but they don't. I tried zooming in and out but sometimes those things are hard to spot even with zooming. How to deal with them?

Usually (or very often), good Protoss players, after building a Robotics bay, build observer and put it to opponent base.   From my perspective if you know Protoss build Robo you should care about that observer.  How do I most effectively deny this observer?   The most often I play Terran and there are few ways for that:   Scan your choke and kill observer with marines. This can fail if observer is not in the scanned screen. That also cost you 50 energy (270 minerals). Observer costs 25/75... if we take gas/mineral exchange rate as 2.5 - it is pretty good price for killing observer... Build Engineering Bay and build few turrets. that costs 150+x*75... also not too bad. This will take time, but could be also useful in a long run (detect DT or other observers, some defense against phenixes and VoidRays). Build Raven (if you have StarPort with tech lab). That costs 100/200 - a little bit expensive for observer hunting, but you could later use Raven for PDD, etc... Anything else?   Questions:   What is the best way to hunt observers? How to deal with opponent observers if you play Zerg? How to deal with opponent observers if you play Protoss?   Thanks a lot!


Given an array nums, we call (i, j) an important reverse pair if i < j   and nums[i] > 2*nums[j].      You need to return the number of important reverse pairs in the given   array.   I am just using the merge sort to do this and while doing merging process, I am piggyback checking the condition nums[i] > 2*nums[j]. However, it is timing out for last test case. Help? .  class Solution(object):     def reversePairs(self, nums):         """         :type nums: List[int]         :rtype: int         """         def merge(left, right):             #print(left, right)             if not left or not right:                 return (0, left + right)             #if everything in left is less than right             left_idx, right_idx, count = 0, 0, 0             merged_output = []             while left_idx < len(left) and right_idx < len(right):                 #print(left[left_idx], right[right_idx])                 if left[left_idx] > 2*right[right_idx]:                     count += len(left) - left_idx                     right_idx += 1                 else:                     left_idx += 1             left_idx, right_idx = 0, 0             while left_idx < len(left) and right_idx < len(right):                 if left[left_idx] > right[right_idx]:                     merged_output += [right[right_idx]]                     right_idx += 1                 else:                     merged_output += [left[left_idx]]                     left_idx += 1             if left_idx == len(left):                 merged_output += right[right_idx:]             else:                 merged_output += left[left_idx:]             return (count, merged_output)          def partition(nums):             count = 0             if len(nums) == 1 or not nums:                 return (0, nums)             pivot = len(nums)//2             left_count, l = partition(nums[:pivot])             right_count, r = partition(nums[pivot:])                       temp_count, temp_list = merge(l, r)             #print(temp_count)             return (count + left_count + right_count + temp_count, temp_list)         return partition(nums)[0]

I'm designing an algorithm to do the following: Given array A[1... n], for every i < j, find all inversion pairs such that A[i] > A[j]. I'm using merge sort and copying array A to array B and then comparing the two arrays, but I'm having a difficult time seeing how I can use this to find the number of inversions. Any hints or help would be greatly appreciated.


Is the preposition "of" necessary in the phrase "outside their comfort zone"?

The word rarely turns up  outside that context.   and     The word rarely turns up outside of that context.   Which one is correct and why?


Is it just a coincidence that 10! = 3! · 5! · 7! and 6! = 3! · 5! or are factorials somehow related to primes in terms of prime factorial factors?

I was playing around with hypergeometric probabilities when I wound myself calculating the binomial coefficient $\binom{10}{3}$. I used the definition, and calculating in my head, I simplified to this expression before actually calculating anything $$ \frac {8\cdot9\cdot10}{2\cdot3} = 120 $$ And then it hit me that $8\cdot9\cdot10 = 6!$ and I started thinking about something I feel like calling generalized factorials, which is just the product of a number of successive naturals, like this $$ a!b = \prod_{n=b}^an = \frac{a!}{(b-1)!},\quad a, b \in \mathbb{Z}^+, \quad a\ge b $$ so that $a! = a!1$ (the notation was invented just now, and inspired by the $nCr$-notation for binomial coefficients). Now, apart from the trivial examples $(n!)!(n!) = n!$ and $a!1 = a!2 = a!$, when is the generalized factorial a factorial number? When is it the product of two (non-trivial) factorial numbers? As seen above, $10!8$ is both.


Consider the following latex code:  \documentclass{article}  \usepackage{amssymb} \usepackage{amsthm}  \newtheorem{thm}{Theorem}  \newcommand{\Zn}[1][n]{\mathbb{Z}_{#1}}  \begin{document}  $\Zn[p]$  \begin{thm}[$\Zn$] \end{thm}  \end{document}   This compiles without errors obtaining:    Now, if I change the \Zn to \Zn[p] inside the theorem title:  \begin{thm}[$\Zn[p]$] \end{thm}   I get the following error when compiling:  ! Argument of \\Zn has an extra }. <inserted text>                  \par  l.14 \begin{thm}[$\Zn[p]                         $] Runaway argument? p) ! Paragraph ended before \\Zn was complete.   Yet the \Zn[p] outside the title works fine. Moreover if I put the command in a group, as in {\Zn[p]}, it compiles successfully with the expected output:  \begin{thm}[${\Zn[p]}$] \end{thm}   Is there something wrong with my definition of \Zn? Or is there a bug in how the theorem environment handles its title? Why does this happen?

I accidentally discovered () that a closing square bracket within an optional argument delimited by [ ] can cause problems.  Here is example code illustrating the issue:  \documentclass{article}   \begin{document}  \tableofcontents  \section[Square brackets ([ and ])]{Square brackets: [ and ]} % bad: the TOC now has "Square brackets ([ and", and the actual title is a mere ")".  Some text.  \section[{Square brackets ([ and ])}]{Square brackets: [ and ]} % good (works as originally intended)  Some text.  \end{document}   The text to be used as the optional (as well as the non-optional) argument contains a ], and this character is not supposed to function as the optional argument terminator but as a matching square bracket/parenthesis. Perhaps this is as it should be, but the question is how to best circumvent any potential problems. Enclosing this in a group works, but I don't know whether doing this has other side effects (perhaps not here in the case of \section but hopefully someone else has a better example of where grouping could lead to a problem). There is no (obvious) way other than writing [{ }] because [ and ] are not normally escaped. That [ and ] are normal characters and bear syntactic function (as optional argument delimiters) creates this potentially problematic situation.  Is simply enclosing the entire optional argument in a group ({ }) a good solution? Are there other/better ways?


everyone! I started learning 3D with Blender about a week ago and now I have a problem. I don't know how to describe it, you can see it on the screenshot that I've attached. Everything started look so sharp and something like artifacts. How can I fix it? Also, suddenly the rotating of the view started rotate relatively to the 3D cursor (I think that it started suddenly). And another one problem - suddenly (who could guess it's suddenly) I wasn't able to scale the view as I wanted and I was attached to the focal view basically.  I do not know really why all of that happens and I kindly ask you to help me, please.

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


I typed something in Bashrc and I can not use commands like cp, gedit, ls, etc. etc anymore. The terminal give me a message like:  Command 'ls' is available in '/bin/ls' The command could not be located because '/bin' is not included in the PATH environment variable. ls: command not found   I tried to restore bashrc, but I need to use cp and I can not use this command either:  Command 'cp' is available in '/bin/cp' The command could not be located because '/bin' is not included in the PATH environment variable. cp: command not found   What could I do? Thank you.

I have been using Ubuntu 12.04 for quite a while and have never had a problem come at me out of the blue like this. I'm trying to install python 3.2 on my Ubuntu system and every time I run the code to compile the python source, I get this error:  'Command 'sudo' is available in '/usr/bin/sudo' The command could not be located because '/usr/bin' is not included in the PATH environment variable. sudo: command not found'   I've also tried running gksudo command to view what my environment shows but I pretty much get the same error.


Sometimes, when I'm trying to close a tab, I'll accidentally close an entire window of tabs in Google Chrome. Is there a plugin or something that I could install to make it so it pops up with a confirmation dialog before closing an entire window?  Thanks!

Chrome always quit when I click on the X button on a tab, without asking me anything!  Even when I close Chrome he do not alert me if I am willing to relay close it?   Many times it happened that accidentally I clicked on X button.


John has got a problem: There is a company with registered trademark: Example. The company sells shoes. It owns the domain example.com. So whenever someone wants to buy this company's shoes they go to example.com. John is a programmer who one day while searching through the web found that the domain example.io was not reserved. He bought the domain with mixed mind. Now, John doesn't want to sell or return the domain. Instead he wants to use it as blog for writing reviews on Example's products. To avoid confusion for visitors, he has placed a disclaimer page and also placed a line in header and footer of the blog saying: We are not associated with "Example.com" in any way. But he is still worried and wants to know Each one of the good reasons why John is not infringing trademark of Example.com and thus is not accountable to any lawsuits???

A search on google for "iphone developer" turns up loads of websites which have "iphone" in them, a trademarked name by Apple.  So I'm led to believe that having a domain such as iphonedeveloper.com is ok? Well, you're still using Apple's trademark, but it would be hard to brand yourself otherwise. You're an IPHONE DEVELOPER... right?  Well, what if I want to provide a website where users pay to get a list of the best offers from Ebay? I might have a domain like ebaydeals.com (I don't... i'm just speculating!).  Now I've heard that places like Ebay are really hot on the trigger and fire out emails to people who register domains like that straight away. But whats the difference?  In both cases I'm making money from the trademark, effectively, so is it just down to how lenient the company who owns the trademark is? Or are there rules? Is there a specific "line" you don't cross?  Thanks


I have been an Android user for the past few years, and recently switched to an iPhone. I was given a used iPhone 6 by someone. But when I try to create an Apple ID, I get an error message stating, This iPhone cannot be used to create an Apple ID and prompts me to the website even after I reset the iPhone completely and removed all the previous accounts and settings.  Why does Apple not allow creating multiple IDs from an iPhone?

On the settings under iCloud, if I try and log in on the ID I created this morning, it says that the maximum number of ID's have been activated on this device. When I try and create a new account underneath, it says that this device is not eligible for one.  How can I resolve this?


Is this defined by the language? Is there a defined maximum? Is it different in different browsers?


how to check mac address of our system through terminal in ubuntu 10.04LTS     ipconfig/all

While looking to find the MAC Address of my computer as it appears to a wireless network, it was recommended that I run ifconfig.  Having executed that command in the Terminal, I noticed that, unlike my other machine, the connected network seemed to be listed as an Ethernet, even though the built in wireless card is the thing I am currently using to post this.  ifconfig output:  lewisgoddard@t42:~$ ifconfig eth0      Link encap:Ethernet  HWaddr 00:0d:60:7b:d2:18             UP BROADCAST MULTICAST  MTU:1500  Metric:1           RX packets:0 errors:0 dropped:0 overruns:0 frame:0           TX packets:0 errors:0 dropped:0 overruns:0 carrier:0           collisions:0 txqueuelen:1000            RX bytes:0 (0.0 B)  TX bytes:0 (0.0 B)  eth1      Link encap:Ethernet  HWaddr 00:0c:f1:53:55:c5             inet addr:192.168.1.10  Bcast:192.168.1.255  Mask:255.255.255.0           inet6 addr: fe80::20c:f1ff:fe53:55c5/64 Scope:Link           UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1           RX packets:716 errors:1 dropped:1 overruns:0 frame:0           TX packets:710 errors:0 dropped:0 overruns:0 carrier:0           collisions:0 txqueuelen:1000            RX bytes:620786 (620.7 KB)  TX bytes:80480 (80.4 KB)           Interrupt:11 Base address:0xe000 Memory:c0210000-c0210fff   lo        Link encap:Local Loopback             inet addr:127.0.0.1  Mask:255.0.0.0           inet6 addr: ::1/128 Scope:Host           UP LOOPBACK RUNNING  MTU:16436  Metric:1           RX packets:182 errors:0 dropped:0 overruns:0 frame:0           TX packets:182 errors:0 dropped:0 overruns:0 carrier:0           collisions:0 txqueuelen:0            RX bytes:19665 (19.6 KB)  TX bytes:19665 (19.6 KB)   Is it possible that Ubuntu is confused somehow?  If not, am I misinterpreting my results, and my MAC Address may not be 00:0c:f1:53:55:c5 ?


when I click various times on "edit" next to my comment, the editor appears multiple times (the second time there are two editors in the first box and another one at the bottom and the third time there are three editors in the first box etc.)  See this screenshot:

Help!!!  I don't know quite what happened, I was getting frustrated, trying to somehow escape the backticks inside the code formatting. I clicked the edit button too many times, and then the above happened. Perhaps I clicked it to fast, I don't know, but I then got lots of boxes.    Edit:  Based on a test case below, the problem is simply caused by pressing edit while you still have an edit box open. They all go away when you press cancel anywhere once. This makes it much easier to reproduce, and, while not very important, perhaps still something to be fixed.  Note on the pattern:  When you click the first time, you get one box, as normal. When you click again, you get one extra empty box at the top, and another normal box above that. At each click, one empty box is added per existing normal boxes, plus one normal box. What is going on?


I have to show that $\mathbb{Z}[i]/\langle 1+4i\rangle\simeq \mathbb{Z}_{17}$.  Attempt:I know that I have to use the isomorphism $\phi (a+bi)=[a]_{17}+4[b]_{17}$ but I don't know how to show that $\ker(\phi)\subseteq\langle 1+4i\rangle$.  Any ideas?

A very basic ring theory question, which I am not able to solve. How does one show that    $\mathbb{Z}[i]/(3-i) \cong \mathbb{Z}/10\mathbb{Z}$. Extending the result: $\mathbb{Z}[i]/(a-ib) \cong \mathbb{Z}/(a^{2}+b^{2})\mathbb{Z}$, if $a,b$ are relatively prime.   My attempt was to define a map, $\varphi:\mathbb{Z}[i] \to \mathbb{Z}/10\mathbb{Z}$ and show that the kernel is the ideal generated by $\langle{3-i\rangle}$. But I couldn't think of such a map. Anyhow, any ideas would be helpful.


When I create a new AP hot-spot, the devices that try to connect cannot login due authentication error.I'm connected via ethernet with static IP configuration.  I followed   These steps creates me a WPA network.  The Ubuntu installation is new and fully updated.

How do I manage my hotspot connected devices or change the hotspot password? I can only see the Network Name, Security type and the Password but I can't seem to manage users or the network properties.


Is there a difference in performance (in mysql) between  Select * from Table1 T1  Inner Join Table2 T2 On T1.ID = T2.ID   And  Select * from Table1 T1, Table2 T2  Where T1.ID = T2.ID   ?

Is there any efficiency difference in an explicit vs implicit inner join? For example:  SELECT * FROM table a INNER JOIN table b ON a.id = b.id;   vs.  SELECT a.*, b.* FROM table a, table b WHERE a.id = b.id;


I’m running Windows 10 on a laptop with a 485gb SSD and a 2.0gb HD. All software is on a 452gb OS (C:) partition on the SSD.     (The SSD also has an EFI partion, 3 OEM partitions,      and 19mb of unallocated space.)   All data is on the lone 1863gb (D:) partiion on the HD.    I want to add Ubuntu as a native dual boot.  With tons of free space, I plan to shrink the OS (C:) partition by 200gb for Ubuntu and additional Linux software (I have already been using LibreOffice for the past year.), and do not see any problem accessing data on the (D) partition from either Ubuntu or Windows.    Am I missing anything?

I'm absolutely new to Linux. I would like to know how to install Ubuntu alongside the pre-installed Windows 8+ OS.  Should I do it with Wubi, or through the Live USB/DVD?  What steps do I need to take to correctly install Ubuntu?


I´m running a binary logistic regression to predict the purchase probability for a product. My model contains mostly dichotomous and categorical variables.  One variable, let´s say "decision maker",  has three categories "x1 = CEO, x2= purchasing manager, x3= others".   So, what to do when the variable "decision maker" is significant but the dummy variable "x2= purchasing manager" is not significant?

After seeking clarification about linear model coefficients  I have a follow up question concerning non-signficant (high p value) for coefficients of factor levels.  Example: If my linear model includes a factor with 10 levels, and only 3 of those levels have significant p values associated with them, when using the model to predict Y can I choose to not include the coefficient term if the subject falls in one of the non-signficant level?  More drastically, would it be wrong to lump the 7 non-significant levels into one level and re-analyze?


In traditional secret sharing schemes, like , first a secret S is generated. Then it is divided into n parts, such that a subset k of the n parts are sufficient to reconstruct S.  My problem is that I already have n individual and independent secrets. Is there a way to come up with a shared secret S from these pre-existing n secrets, such that a subset k of the n parts are sufficient to reconstruct S?

In usual $(t, n)$ secret sharing schemes, a secret $S$ is split into $n$ parts so that any $t$ out of $n$ parts reconstruct the original secret. So, suppose that there is a group of $n$ participants each one has a secret $x_i$ ($x_i$ may be its private key). My question is, is it possible to create a secret $S$ using the prexisting secrets $x_i$ ($i=1...n$) so that with any $t$ out of $n$ from these secrets ($x_i$) we can find the secret $S$?


Suppose that the arithmetic operation on extended complex plane are defined via arithmetic operations on the corresponding sequences, why $∞-∞，0*∞，∞/∞，0/0 $are not defined? Can anyone give me some example about that?  I know that ∞ + ∞ is undefined because if we have two sequences:  $1, 3, 3, 5, 5, 7, 7, 7, 9,....$    and   $-1,-2,-3,-4,-5,-6,-7,-8,....$  the sum of the above sequences will be:  $0,1,0,1,0,1,0,1,...$  which is not converging or diverging. so ∞+∞ is meaningless.  Can I use it in $ ∞-∞，0*∞，∞/∞，0/0$?  Can anyone give me some example about that?

Assuming arithmetic operations on $\overline{\mathbb{C}}$ (that's the extended complex plane) are defined via arithmetic operations on the corresponding sequences, I need to give examples showing why $0\cdot \infty$, $\infty/\infty$, and $0/0$ are meaningless.  I also had to show the same thing for $\infty - \infty$, but that was easy: Consider the sequences $\{1,3,3,5,5,7,7,9,\cdots \}$ and $\{1,2,3,4,5,6,7,8,\cdots \}$, both of which belong to the class $\infty$ (i.e., the equivalence class of all sequences converging to $\infty$). Then, subtracting the second sequence from the first, term-by-term, we obtain the resulting sequence $\{0,1,0,1,0,1,\cdots\}$, which does not belong to any convergence class, since it has no limit.  However, I can't approach the three cases I'm asking on here about in the same way. I must admit, I'm a little confused as to what is being asked. For reference, it is problems 2-4 on p. 79 of Markushevich's Theory of Functions of a Complex Variable, Vol I.  If someone could furnish me with an example, at least for $0 \cdot \infty$, and maybe either $0/0$ or $\infty/\infty$, perhaps I could use that to help me figure out the other case on my own.  Thank you.


I already found out that this sequence is bounded above and $a_n <2 \forall n \in \mathbb Z_+ $  I think I'm missing a point as I can't think of a way to prove that the sequence is increasing.

Problem  The sequence $(a_n)_{n=1}^\infty$ is given by recurrence relation:   $a_1=\sqrt2$, $a_{n+1}=\sqrt{2+a_n}$.   Evaluate the limit $\lim_{n\to\infty} a_n$.  Solution   Show that the sequence $(a_n)_{n=1}^\infty$ is monotonic. The statement $$V(n): a_n < a_{n+1}$$ holds for $n = 1$, that is $\sqrt2 < \sqrt{2+\sqrt2}$. Let us assume the statement holds for $n$ and show that $V(n) \implies V(n+1)$. We have that $$a_n < a_{n+1}.$$ Adding 2 to both sides and taking square roots, we have that $$\sqrt{2+a_n} < \sqrt{2+a_{n+1}},$$ that is $a_{n+1} < a_{n+2}$ by definition. Find bounds for $a_n$. The statement $$W(n): 0 < a_n < 2$$ holds for $n=1$, that is $0 < \sqrt2 < 2$. Let us assume the statement holds for $n$ and show that $W(n) \implies W(n+1)$. We have that $$0 < a_n < 2.$$ Adding two and taking square roots, we have that $$0 < \sqrt2 < \sqrt{2+a_n} < \sqrt4 = 2.$$ The limit $\lim_{n\to\infty} a_n$ exists, because $(a_n)_{n=1}^\infty$ is a bounded monotonic sequence. Let $A = \lim_{n\to\infty} a_n$. Therefore the limit $\lim_{n \to\infty} a_{n+1}$ exists as well and $\lim_{n \to\infty} a_{n+1} = A$. (For $(n_k)_{k=1}^\infty = (2,3,4, \dots)$, we have that $(a_{n_k})_{k=1}^\infty$ is a subsequence of $(a_n)_{n=1}^\infty$, from which the statement follows.) We have that $a_{n+1} = f(a_n)$. That means that $A = \lim_{n\to\infty} a_n = \lim_{n \to\infty} {f(a_n)} = f(\lim_{n \to\infty} a_n) = f(A) = \sqrt{2 + A}$. Solving the equation $A = \sqrt{2 + A}$, we get $A = -1 \lor A = 2$. Putting it all together, we get that $A = 2$, because the terms of the sequence are increasing and $a_1 > 0$.   Is my solution correct?


I was watching friends lately and on that show Ross said "I haven't had sex in a very long time". I wonder why he didn't said "I haven't had sex for a very long time" although 'in a very long time' sounds more native and correct but why not he used  'for a very long time '.   So, this is my question when do we use 'in a very long time' and when do we use 'for a very long time'.

Now the cubs are growing, fed on mom's milk, but mom herself hasn't eaten in five months, and is getting thinner by the day.   What does in mean here, and how would the meaning of that piece change if for were used?


I am making a number guessing game in Java, where the program displays a number, in a 1 to 10 range, and you have to either guess if the next number will be lower or higher than the current one. But there seems to be an issue when i get it correct i am supposed to get a point added to my score but instead it just does the method for when I get the guess wrong.  class csjava {     public static void main(String[] args)     {         Random dom = new Random();         Random dom2 = new Random();         Scanner input = new Scanner(System.in);         int score = 0;         System.out.println("Guess if next number will be higher or lower                        Score:" + score);         int rnd = dom.nextInt();         int rnd2 = dom2.nextInt();         String  lo = "lower";         String hi = "higher";         if(score ==10)         {             System.out.println("You win!");         }         while(score != 10)         {             System.out.println(dom.nextInt(10-1)+1);             String in = input.nextLine();             if(in == lo)             {                 System.out.println(dom2.nextInt(10-1)+1);                 if(rnd2 < rnd)                 {                     score = score + 1;                 }             }             else             {                 System.out.println("Nope, try again.");             }             if(in == hi)             {                 System.out.println(dom2.nextInt(10-1)+1);                 if(rnd2 > rnd)                 {                     score = score + 1 ;                 }             else             {                 System.out.println("Nope, try again.");              }         }     } }

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


I am trying to get the sandgun in Terraria, and it's impossible for me to get any mandibles after killing antlions! Is there a specific pre-hardmode weapon that increases chances of getting mandibles? Thanks.

Some items in Terraria drop only very rarely from certain enemies. It's a pain having to farm so many enemies to try to get these rare items. Is there any way to make them drop more often?


I used to 301 redirect expired domains to my site and now I think I made a mistake. If we redirect more than a single domain to a particular website, will hurt SEO?

I am developing a entertainment website and have found more than 4 entertainment domains (expired domains). Domain authority of these domains are 25 or more.   If I will redirect these domain to my site then will this help my site or will penalize website?


The sum $\sum_{k=1}^nk(k!)$ can be easily calculated by noting $k(k!)=(k+1)!-k!$. Is there a way to calculate the sum nicely using a combinatorial argument. Is it possible to notice it is $(n+1)!-1$ combinatorially?

Prove: $\displaystyle\sum_{k=1}^n k k!=(n+1)!-1$ (preferably combinatorially)   It's pretty easy to think of a story for the RHS: arrange $n+1$ people in a row and remove the the option of everyone arranged to height from shortest to highest, but it doesn't hold up for the LHS.   Alternatively, trying to visualize the LHS, I noticed that it's like a right angle tetrahedra:  1  2!+2!  3!+3!+3!  ...  But it doesn't help to see a connection to the RHS.  Note: no integrals or gamma function nor use of other identities without proving them nor generating functions.


Prove that having 100 whole numbers, one can choose 15 of them so that the difference of any two is divisible by 7.

How can we prove with the pigeonhole principle that having $100$ whole numbers, one can choose $15$ of them so that the difference of any $2$ is divisible by $7$?


I gotta show if or if not those $ 2 $ matrices are similar:   $$     \left(\begin{matrix}     3 & 2 & -2 \\     1 & 4 & 0 \\     -2 & 1 & -1 \\     \end{matrix}\right) $$    $$     \left(\begin{matrix}     1 & 3 & -1 \\     3 & 3 & 1 \\     -2 & 1 & 2 \\     \end{matrix}\right) $$  I already calculated their determinant but it's equal so nothing there. Is it possible to show it based on their polynominal?

I have two $2\times 2$ matrices, $A$ and $B$, with the same determinant. I want to know if they are similar or not.  I solved this by using a matrix called $S$: $$\left(\begin{array}{cc} a& b\\ c& d \end{array}\right)$$ and its inverse in terms of $a$, $b$, $c$, and $d$, then showing that there was no solution to $A = SBS^{-1}$. That worked fine, but what will I do if I have $3\times 3$ or $9\times 9$ matrices? I can't possibly make system that complex and solve it.  How can I know if any two matrices represent the "same" linear transformation with different bases?  That is, how can I find $S$ that change of basis matrix?  I tried making $A$ and $B$ into linear transformations... but without the bases for the linear transformations I had no way of comparing them.  (I have read that similar matrices will have the same eigenvalues... and the same "trace" --but my class has not studied these yet. Also, it may be the case that some matrices with the same trace and eigenvalues are not similar so this will not solve my problem.)  I have one idea. Maybe if I look at the reduced col. and row echelon forms that will tell me something about the basis for the linear transformation? I'm not really certain how this would work though? Please help.


Twice now I spent a ton of time in edit mode, and upon exiting I noticed it seemed as if my entire scene reverted to my last save. I checked, and there is not a shortcut to "revert" but somehow I am reverting changes when I exit edit mode. Is there some key-combo/shortcut that I must be doing that is causing this? Thanks!

From time to time I lose all edits because of undo in Object Mode. If I enter immediately after Undo in Edit Mode I can't redo, and switching again in Object results in losing all edit history.  How can I resolve this? Separating undo history by mode or linear/unified will both be acceptable.  Edit:I think the most preferable solution will be to disable/skip edit undos when in object mode through an addon.


We have two toilets that don't flush well.  You have to hold the handle down for the entire flush, and even so they don't flush enough water.  Inside the tanks are plastic baffles that seem designed to limit the amount of water per flush.  It looks like they were installed with the tanks; they're mounted between the tank floor and the inner drain flange:    I'm all for water conservation, but this is a really poor design; the water flowing in from the top (instead of from all around) keeps knocking the valves closed.  Is there any reason (except for water usage) that I shouldn't just cut these out with a Dremel, leaving an inch or two in place?  I would prefer not to take the tanks off.

I recently bought an older house, and the toilet tank is leaking.  In exploring the issue and googling around for toilet repair, I saw no mention of one of the parts that is in my toilet tank.  Within the tank, there is a smaller plastic container that surrounds the flush valve.  It seems to restrict the amount of water that ends up being used per flush, so perhaps it was added to reduce water consumption?  What is this thing, and how does its presence affect my approach toward replacing the different pieces of the toilet?


Does the Linux kernel use original Unix code or do they share the idea? Since both are written in C, is that true?

So, there are lots of different versions of Unix out there: HP-UX, AIX, BSD, etc. Linux is considered a Unix clone rather than an implementation of Unix. Are all the "real" Unices actual descendants of the original? If not, what separates Linux from Unix?