I am looking for a correct proof of this statement: If $G$ is a group such that $G/Z(G)$ is cyclic, then $G$ is commutative.  Proof: $G/Z(G)$ is isomorphic to $\operatorname{Inn}(G)$ and is cyclic, and then for every $a$ and $b$ in $G$ the inner isomorphisms $\gamma_a$ and $\gamma_b$ satisfy $\gamma_a \gamma_b = \gamma_{ab} = \gamma_{ba} = \gamma_b \gamma_a$, and therefore for every $a,b \in G$, $ab = ba$.  Is that proof complete, or am I missing something? Thanks a lot for the help.

Continuing my work through Dummit & Foote's "Abstract Algebra", 3.1.36 asks the following (which is exactly the same as exercise 5 in ):     Prove that if $G/Z(G)$ is cyclic, then $G$ is abelian. [If $G/Z(G)$ is cyclic with generator $xZ(G)$, show that every element of $G$ can be written in the form $x^az$ for some $a \in \mathbb{Z}$ and some element $z \in Z(G)$]      The hint is actually the hardest part for me, as the quotient groups are somewhat abstract. But once I have the hint, I can write:  $g, h \in G$ implies that $g = x^{a_1}z_1$ and $h = x^{a_2}z_2$, so \begin{align*}gh &= (x^{a_1}z_1)(x^{a_2}z_2)\\\  &= x^{a_1}x^{a_2}z_1z_2\\\ & = x^{a_1 + a_2}z_2z_1\\\ &= \ldots = (x^{a_2}z_2)(x^{a_1}z_1) = hg. \end{align*} Therefore, $G$ is abelian.  1) Is this right so far?  2) How can I prove the "hint"?


I have an iOS drawing app with buttons that let a user choose colors to draw with. Since my brush uses RGB values but my color constants are UIColors, I need to convert. I tried  private var currentButton: UIButton? {     willSet{         currentButton?.layer.borderWidth = 0     }     didSet{         currentButton?.layer.borderWidth = 2         let index = (currentButton?.tag)! - 1         drawView.brush.blue = colors[index].ciColor.blue //Here is where I get the error         drawView.brush.green = colors[index].ciColor.green         drawView.brush.red = colors[index].ciColor.red     } }   Which I found in another StackOverflow question. However, when I try to get an RGB value in line 8 I get this error:  Terminating app due to uncaught exception  'NSInvalidArgumentException', reason: '*** -CIColor not defined for the UIColor UIExtendedSRGBColorSpace 1 1 1 1; need to first convert colorspace.'   It clearly says that I need to convert color space. But CIColor.colorSpace is get-only. What am I doing wrong?

I'm creating a color object using the following code.  curView.backgroundColor = [[UIColor alloc] initWithHue:229 saturation:40 brightness:75 alpha:1];   How can I retrieve RGB values from the created color object?


I have a  file (example), which was generated from TeX. Is it possible to convert into a tex file, or obtain the .tex source?  Thanks

I know that hardly any information is passed to the PDF when a .tex file is compiled.  But is there a tool that can convert a PDF document back to (La)TeX?


Deleted a folder (just regular old empty trash) on my MacBook Pro internal SSD that I thought I was backed up, turns out it wasn't. I stopped using the computer as to preserve the blocks where the data is written and booted up an old computer to do recovery. I Don't have any experience with data recovery software, wondering if anyone knows any good applications? Preferably that allow me to preview deleted data before I pay for the application (or if there's a free one that I'm overlooking? But I'm not hopeful about that). Lots of things come up on google but it's hard to differentiate one from another in terms of quality.

I am a longtime Windows user, recently switched to Mac. I replaced folder with another folder (they had the same name) thinking that OS X will merge the contents of both folders. But OS X deleted the original folder and replaced it with the new one. Windows merges both the folders (I do this often in Windows). I have now lost hundreds of files. I haven't enabled Time Machine. I've tried using Finder's Undo, but that doesn't work.  Currently, I am trying to recover my data using . It shows estimated time as 7 hours, 31 minutes. Does anyone know any free data recovery software that's faster and more powerful?


(a) Suppose that $X$ and $Y$ are i.i.d. $N(0,1)$. Show $\frac{X+Y}{\sqrt{2}}\stackrel{d}{=}X\stackrel{d}{=}Y$.   (b) Conversely: Suppose $X$ and $Y$ are i.i.d. with mean $0$ and variance $1$, and suppose further that \begin{equation*} \frac{X+Y}{\sqrt{2}}\stackrel{d}{=}X\stackrel{d}{=}Y \end{equation*} Show that both $X$ and $Y$ have a $N(0,1)$ distribution. (Use the Central Limit Theorem)  I have solved part (a) as follows: (a) Since $X,Y\in N(0,1)$, we have that: $\phi_X=\phi_Y=\exp\big(\frac{-t^2}{2}\big)$, thus: \begin{align*} \phi_{\frac{X+Y}{\sqrt{2}}}&=\phi_{\frac{X}{\sqrt{2}}+\frac{Y}{\sqrt{2}}}\\ &=\phi_{\frac{X}{\sqrt{2}}}\phi_{\frac{Y}{\sqrt{2}}} \quad\text{by independence}\\ &=\phi_X\big(\frac{t}{\sqrt{2}}\big)\phi_Y\big(\frac{t}{\sqrt{2}}\big)\\ &=\exp\big(\frac{-(t/\sqrt{2})^2}{2}\big)\exp\big(\frac{-(t/\sqrt{2})^2}{2}\big)\\ &=\exp\big(\frac{-t^2}{4}+\frac{-t^2}{4}\big)\\ &=\exp\big(\frac{-t^2}{2}\big)\\ &=\phi_X=\phi_Y\\ &\iff \frac{X+Y}{\sqrt{2}}\stackrel{d}{=}X\stackrel{d}{=}Y \end{align*} but I am stuck on part (b). In particular, I am not sure how to bring the CLT into it, any help would be greatly appreciated.

Suppose $X$ and $Y$ are independent with mean zero and variance 1, and $\frac{X+Y}{\sqrt{2}}\overset{d}=X\overset{d}=Y$. Use the CLT to show that $X\sim \mathcal N(0,1)$.  I saw in many places that set $\frac{S_{2^n}}{\sqrt{2^n}}$ to prove the problem. Is it feasible to go through the proof by using $\frac{S_{2n}}{\sqrt{2n}}$?    I see, we need to set $\frac{S_{2^n}}{\sqrt{2^n}}$. Thus $X\overset{d}=\frac{S_{2^n}}{\sqrt{2^n}}\overset{d}\to \mathcal N(0,1)$.


I am getting clause like this #ff0000,'#000'. But the problem is this I have to pass there values to a stored procedure as parameter to get the color names based on this color codes.  Here is my stored procedure   @ColorCode NVARCHAR(150) AS BEGIN     SET NOCOUNT ON;      SELECT *      FROM color      WHERE code IN (@ColorCode)   I want to pass these value for the IN clause, using a parameter. How can I do this?  Please suggest

How do I parameterize a query containing an IN clause with a variable number of arguments, like this one?  SELECT * FROM Tags  WHERE Name IN ('ruby','rails','scruffy','rubyonrails') ORDER BY Count DESC   In this query, the number of arguments could be anywhere from 1 to 5.  I would prefer not to use a dedicated stored procedure for this (or XML), but if there is some elegant way specific to , I am open to that.


I am trying to run the following query locator:   Database.getQueryLocator('select ' + TrackingNumberString + ',Carrier_Status__c from '                           + MainObjectString + ' where ECS__Shipped_Time__c = LAST_N_DAYS:'                           + DaysBackString + ' and Carrier_Status__c != ' + exclusion1);   Where:  TrackingNumberString = Tracking_Number_Field__c  MainObjectString = Main_Object__c  DaysBackString = 1  and exclusion1 = Delivered   The fields are correct, and I cannot simply insert 'Main_Object__c' into the query string because it is located from another query using a custom setting.  Also it isn't really related to my question.  I am getting the following error:     12:20:07:059 FATAL_ERROR System.QueryException: Variable does not   exist: Delivered   So my question is:  How can I write the code so that 'and Carrier_Status__c' does not equal the string: Delivered?  Should I do something where I extract the string information from Carrier_Status__c then run it through a series of if statements to see if it equals exclusion1?  Or is there some way to type it in a query so that Carrier_Status__c does not equal the string value of exclusion1?  Any help is appreciated. If you need more code to help, just ask please.

Declared a string and assigned SOQL value as shown below. While running I am getting an error.   String country = 'United States'; String accountQuery = 'SELECT Id,BillingPostalCode,County_Name__c '+      'FROM Account WHERE zipCodeLen__c =9 AND AND BillingCountry = '+ Country;   System.QueryException: unexpected token: 'AND'  System.QueryException: expecting a colon, found 'United'


I have the following in my httpd.conf file  NameVirtualHost *:80  <IfModule mod_vhost_alias.c>   <VirtualHost *:80>     ServerAlias *     UseCanonicalName Off     LogFormat "%V %h %l %u %t \"%r\" %s %b" vcommon     CustomLog /var/log/httpd/access_log vcommon     VirtualDocumentRoot /web-data/vhosts/%0/httpdocs     VirtualScriptAlias  /web-data/vhosts/%0/httpdocs   </VirtualHost> </IfModule>   This works great for dynamic hosting. However, I can't figure out how to make https requests work the same way. What do I need to add to this so that https and http for the same domain request get sent to the same folder?

Goals:   If the user support SNI and hit myurl1.server.com (https) or myurl2.server.com (https) it will match the right vhost. (the last 2 vhosts) If the user does not support SNI and hit myurl1.server.com (https) or myurl2.server.com (https) it will be catch by the fallback vhost (the first on port 443). It contains the SAN certificate and it  will hit the server again to do the match. This time it will hit the last 2 vhost.  If the user enter an unknown url with either http or https it will be catch in the first vhost that show a error page.   I have tested all 3 goals and it's working fine.  Questions:   When the user is hitting the SAN vhost (https) which make a new request to it self. How does Apache know it will match the last 2 vhost (443) when the proxypass in SAN vhost is using http(80) When the user is hitting the SAN vhost I can't see any requests in the SAN access log. The requests only appears in the  last 2 vhost even if it goes through the SAN vhost. However I can see some bot requests in the SAN access log.   The code only contains the important parts.  NameVirtualHost *:80 NameVirtualHost *:443  <VirtualHost *:80>   show error page </VirtualHost>  <VirtualHost *:443>   SSLCertificateFile san.crt   CustomLog san-access.log    ProxyPass / http://my-local-url-server/   ProxyPassReverse / http://my-local-url-server/ </VirtualHost>  <VirtualHost *:443>   ServerName myurl1.server.com   SSLCertificateFile myurl1.crt   CustomLog myurl1-access.log    ProxyPass / http://mybackend1/   ProxyPassReverse / http://mybackend1/ </VirtualHost>  <VirtualHost *:443>   ServerName myurl2.server.com   SSLCertificateFile myurl2.crt   CustomLog myurl2-access.log    ProxyPass / http://mybackend2/   ProxyPassReverse / http://mybackend2/ </VirtualHost>


I'm currently running Windows 7 but I'll probably get a new PC with Windows 10 Pro this year.   I've heard horror stories about automatic updates with Windows 10 happening at unpredictible times and causing big problems so I'm trying to understand them.    implies you can "defer" them but was a little unclear about defer them to exactly when, or how long?   Likewise the suggestion about Active Hours was a little unclear about how rigorously Microsoft follows it, i.e., if I say my "active" hours are 8AM to 6AM, does that guarantee that updates will only happen between 6-8AM?  I do professional video production so I'm often in the middle of big projects with tight schedules, and my PC is often running long multi-hour exports or conversions.   Overnight I'm often running batch-jobs, complete backups, malware scans or de-frags.  So an unscheduled reboot or interruption could be disastrous.     How do I exercise precise control over this risk?   I'd be perfectly happy to run an Update every single day as long as I could start it manually to make sure that no backups, exports, de-frags are running at the time.

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


I'm having a tricky time understanding the statement:      we lose $n−1$ [degrees of freedom] by computing the product   deviations [in $cov(x,y)$]   I'm not necessarily looking for an overview of degrees of freedom, just an explicit pointer to grasp this claim. It comes from  Full quote:     You may be perplexed that we average the product deviations [in $cov(x,y)$]    by dividing by $n−1$ rather than $n$. The best explanation is that in the   probability model discussed below, the sample covariance is an   unbiased estimator of the distribution covariance. However, the mode   of averaging can also be understood in terms of degrees of freedom, as   was done for sample variance. Initially, we have $2n$ degrees of freedom   in the bivariate data. We lose two by computing the sample means $m(x)$   and $m(y)$. Of the remaining $2n−2$ degrees of freedom, we lose $n−1$ by   computing the product deviations. Thus, we are left with $n−1$ degrees   of freedom total.   Thanks, if you can rephrase the claim to help with understanding?

The denominator of the (unbiased) variance estimator is $n-1$ as there are $n$ observations and only one parameter is being estimated.  $$ \mathbb{V}\left(X\right)=\frac{\sum_{i=1}^{n}\left(X_{i}-\overline{X}\right)^{2}}{n-1} $$  By the same token I wonder why shouldn't the denominator of covariance be $n-2$ when two parameters are being estimated?  $$ \mathbb{Cov}\left(X, Y\right)=\frac{\sum_{i=1}^{n}\left(X_{i}-\overline{X}\right)\left(Y_{i}-\overline{Y}\right)}{n-1} $$


I'm using a basic license of ArcGIS 10.2.2 for Desktop.  I have a point feature class layer and I uploaded it twice for representing two features. First is a type of person and second is the performances level of this person. Sometimes they are overlapped.  How can I split a bit between points of each layer so I can see all of them?  I can't use xy offset because they have not necessarily a different symbology &and I have only basic license.

I have a series of points representing animal observations. Many of them overlap, having the exact same coordinates, and this is causing me trouble when I want to run some analytical tools which requite no identical points. I was wondering if there's any tool that can add some "noise" to the coordinates, that's to say, adding some random decimal values at the end in order to obtain slightly different coordinates which are still close enough in space so as to not really modify the observation. I've heard about such a tool, but I can't find it, at least in ArcGis 10. Maybe there's another software that can do it? Thanks!


I met the problem on move an off screen window back on-screen on mac. The application is Adobe Element 11 Organizer. It can't be solve by adjust desktop resolution, or maximum the app window, or connect to a extra monitor.  Since I can't add a possible answer due to reputation limit, start a new question here.

It seems that Mac OS X 10.6.1 Snow Leopard has a tendency to leave some windows off-screen at times, especially when I disconnect an external monitor from my MacBook. How can I move the window back on-screen when it's not possible to grab the title bar and drag it back onto the screen?   recommends adjusting your screen resolution downward to have off-screen windows "snap back into view" and then adjust your screen resolution back to its original setting. In OS X 10.4 Tiger, I had a script that brought all off-screen windows back on-screen, but in my upgrades to Leopard and now Snow Leopard, I don't seem to have that script.  Any better solutions out there?


We will be changing the collation of our databases in a few months. I am setting up an environment, to test the new collation with my application.  I have created a database with our new collation and want to write data into the new database.  Database1: SQL_Latin1_General_CP1_CI_AS Database2: Latin1_General_CP1_CI_AS_WS    If I run the following query:  INSERT INTO Database2.table1 SELECT * FROM Database1.table1   ...will SQL use the collation of Database2 or Database1 to write the data?  Both databases are on SQL Server 2012.  The collation for Database2 is Latin1_General_CP1_AS_WS

We're moving from SQL 2005 [Instance and DB have collation of SQL_Latin1_General_CP1_CI_AS]  to SQL 2008 [which defaults to Latin1_General_CI_AS].  I completed a SQL 2008 R2 installation, and used default Latin1_General_CI_AS collation, with the restoration of the database still on SQL_Latin1_General_CP1_CI_AS. The excepted problems occurred - the #temp tables where in  Latin1_General_CI_AS whilst the db was in  SQL_Latin1_General_CP1_CI_AS and this is where I am now - I need advice on the pitfalls now please.  On installation of SQL 2008 R2, I have the option on installation to use 'SQL Collation, used for backwards compatibility' where I have the option to select the same collation as the 2005 database : SQL_Latin1_General_CP1_CI_AS.   This will allow me to not have problems with #temp tables, but are there pitfalls? Would I lose any functionality or features of any kind by not using a "current" collation of SQL 2008? What about when we move (e.g. in 2 years ) from 2008 to SQL 2012? Will I have problems then? Would I at some point be forced to go to Latin1_General_CI_AS? I read that some DBA's script complete the rows of complete databases, and then run the insert script into the database with the new collation - I'm very scared and wary of this - would you recommend doing this?


Why is my simple Java programm runs quickly on my local computer and  too slow on Windows 2008 Server?  Programm code:  public static void main(String[] args) {     long startTime;     long endTime;     long totalTime;      startTime = System.currentTimeMillis();      for (int a=1; a < 100000; a++) {         System.out.println("Checking");      }      endTime   = System.currentTimeMillis();     totalTime = endTime - startTime;     System.out.println("TEST1 time:"+totalTime);      startTime = System.currentTimeMillis();      double sum = 0;      for (int a=1; a < 1000000; a++) {         int input = 100;          for(int counter=1;counter<input;counter++){             sum += Math.pow(-1,counter + 1)/((2*counter) - 1);         }      }      endTime   = System.currentTimeMillis();     totalTime = endTime - startTime;     System.out.println("TEST2 time:"+totalTime+" pi="+sum); }   Local computer output:  Checking Checking Checking Checking TEST1 time:427 TEST2 time:7261 pi=787922.5634628027   Windows server output:  Checking Checking Checking Checking Checking Checking TEST1 time:15688 TEST2 time:25280 pi=787922.5634628027   Local computer hardware and soft: Intel Core (TM) i7-2600 CPU @ 3.40GHz Windows 7 Professional 8G RAM  Server hardware and soft:  Intel Xeon(R) CPU E5-2603 @ 1.60GHz  8G RAM Windows Server 2008 Standart Version 6.0  Both computer and server are free from another processes.  May be I have to apply some parametrs to java vm?

How do you write (and run) a correct micro-benchmark in Java?  I'm looking for some code samples and comments illustrating various things to think about.  Example: Should the benchmark measure time/iteration or iterations/time, and why?  Related:


How can I mirror the screen to a smart TV from Ubuntu ?

I couldn't find anything about Ubuntu acting as a  receiver or sender.   Can it work at all? Are there hardware prerequisites? Is WiFi a requirement or can it work over LAN or another kind of network connection? WiFi direct seems to be a necessary requirement, is it a sufficient one? (i.e. if a system supports WiFi direct does that mean it supports Miracast?) Are there differences in support between receiving/sending? How is the latency? (compared to the competition, i.e. VNC, commercial Miracast devices, etc.) How do I actually use it, if it's difficult?   Specifically, I plan to use it together with an Android phone (4.x Jelly Bean).


I was stacking loot boxes to open them all when I reach 100. Some days ago I logged on the PTR. I saw that I had 40 boxes (on normal server I got 47, so the copy of the data on PTR was 2-3 days old) and knowing that it won't affect my boxes on the normal server, I opened them and I was quite disappointed. Now I read this question:     I started wondering if it possible that the content of the loot boxes is generated at the time when the copy to PTR was made or the content is carried over from the normal server?

Are the contents of a loot box determined at the time it is awarded or when it is opened?  For example, if you collect multiple loot boxes before a special event but opened them during the special event, would they have the potential of spawning rewards from that event?


BIG EDIT: I have solved this. I just disabled the texture from Cycles and I am manually adding the correct ones.  I have a Blender project I am working on for Christmas, and I had to rig many characters. I rigged them in Cycles Render, but I figured out that if I want a smooth output, I need Blender Render. How do I switch from Cycles Render to Blender Render without deleting the textures? Please respond before the 24th, as I am trying to make this as a Christmas project.  EDIT: This question is different than the thought-to-be duplicate because I am only moving the textures, not nodes. I also tried the accepted answer and it did not solve my problem.

Is it possible to have a mesh coloured and textured in cycles and then have it displayed in internal?  The only reason I ask is because I am building a log cabin and want to put some windows in. When I have done glass in cycles (Nodes) it looks much better (realistic) but when I try to do this and go back into blender internal to finish the rest of the log cabin off the window and the mesh surrounding the window becomes undefined and discoloured.  Is this because I am trying to put cycles into internal or because I am doing something wrong?


I am fairly new to C++ and I was experimenting with headers, this may be a simple problem but I couldn't figure it out.  I want to define a function that takes type T argument in header file then call it from main but the code does not compile.  I am using Visual Studio, Microsoft Visual C++ 2019.  //Header1.h #pragma once  namespace sout {     template <typename T>     void Print(T); }   //Header1.cpp #include <iostream> #include "Header1.h"  template <typename T> void sout::Print(T t) {     std::cout << t << std::endl; }   //Main.cpp #include <iostream> #include "Header1.h"  int main() {     sout::Print("dsa");      return 0; }   Main.obj : error LNK2019: unresolved external symbol "void __cdecl sout::Print<char const *>(char const *)" (??$Print@PBD@sout@@YAXPBD@Z) referenced in function _main   I solved like this below;  //Header1.h #pragma once #include <iostream>  namespace sout {     template <typename T>     void Print(T t) {         std::cout << t << std::endl;     } }   //Header1.cpp #include <iostream> #include "Header1.h"  template typename void sout::Print<const char*>(const char* t); template typename void sout::Print<int>(int t); template typename void sout::Print<double>(double t); template typename void sout::Print<float>(float t);   //Main.cpp #include <iostream> #include "Header1.h"  int main() {     sout::Print("dsa");     sout::Print(5);     sout::Print(5.5);     sout::Print(5.3f);      return 0; }

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


How does one insert some vertical spacing between two cases for the output of the following script? \begin{cases} a+b \\ c+d  \end{cases}

I have this case formula which I need to make a little more readable by adding a little more space, vertically, between the two cases.  \begin{cases} f = -\frac {w_1*m + w_2*\frac{-d}{d_M} + w_3*\frac{r}{N} + w_4*s}{w_1+w_2+w_3+w_4} &\hbox{when }m \geq t \\ f = -\frac {w_1*m + 5*w_2*\frac{-d}{d_M} + w_3*\frac{r}{N} + w_4*s}{w_1+w_2+w_3+w_4} & \hbox{when } m< t \end{cases}     How to add an extra space in the latex case above?


Is it possible to look up a Stack Exchange user by their email address?   If so, how can I disable this feature for my account?

I might be ignorant if there exists such functionality. Can I search for a friend on Stack Exchange with their email address?.


I know that both MD5 and SHA1 are considered cryptographically broken now that collisions can reasonably be computed. The question I have is: What is the likelihood that a collision could be found for data hat is hashed by each independently?  For instance, would it be reasonably be possible to do something such as …  [Hashed Doc] => [MD5] [Hashed Doc] => [SHA1]  [Fake Doc] + [Padding] => [MD5] [Fake Doc] + [Padding] => [SHA1]   where the adjusted padding for the fake document caused both signatures to remain the same?

I was recently reading that MD5 is "broken" because it's pretty easy to generate collisions (like 2^(L/2)). And the SHA1 (theoretically) fares no better. The solution seems to be hash algorithms that are very slow in comparison.   I am wondering why can't people combine these fast algorithms to get the best of both security and speed? What would be the time complexity to generate a simultaneous MD5 and SHA1 collision? And if it's hard enough, would these make a viable candidate for collision resistant hash applications?  (By simultaneous collision I mean generating a string with same MD5 and SHA1)


I'm planning an installation of Lubuntu in a Nokia Booklet 4G, but I don't know much about partition tables and formats.  Which format would be good for the hardware?

What partitioning scheme do you recommend for a desktop? I've always created three or four primary partitions -- root, swap, home, and sometimes a separate boot partition. Ubuntu's default install offers LVMs. I've never had to add additional drives or space, so it never seemed like a big deal. Whenever I do a fresh install, though, I always think there might be a better way.


My attempt :  Let $f : \mathbb R^{n} \longrightarrow \mathbb R^{m}$ be differentiable at $x = c \in \mathbb R^{n}$.Then there exists a linear operator $T_{c} : \mathbb R^{n} \longrightarrow \mathbb R^{m}$ such that  $f(c + h) - f(c) = T_{c} (h) + ||h|| E_{c} (h)$ , where $E_{c} (h) \rightarrow 0$ as $h \rightarrow 0$.So taking limit as $h \rightarrow 0$ on both sides of the above equation we obtain  $$\lim _{h \rightarrow 0} [f(c + h) - f(c)] = \lim_{h \rightarrow 0} T_{c} (h)$$.  If we can show that $T_{c}$ is continuous at $0$ then our purpose will be served.  But I find difficulty to show this.Please help me.  Thank you in advance.

From      Every linear function on a finite-dimensional space is continuous.   I was wondering what the domain and codomain of such linear function are?   Are they any two topological vector spaces (not necessarily the same), as along as the domain is finite-dimensional? Can the codomain be a different normed space (and may not be finite-dimensional)?  I asked this because I saw elsewhere the same statement except the domain is a finite-dimensional normed space, and am also not sure if the codomain can be a different normed space (and may not be finite-dimensional).  Thanks and regards!


I have installed executable files for  compiler and interpreter in my Ubuntu system.  But now every time I have to compile my .cm file I have to go to the program folder and run ./bacc and ./bainterp.  Can anyone tell me how to set environment variables for these programs, so that I can use them like by simple typing bacc / bainterp from any directory (just like we use gcc)?

I'm wondering where a new path has to be added to the PATH environment variable. I know this can be accomplished by editing .bashrc (for example), but it's not clear how to do this.  This way:  export PATH=~/opt/bin:$PATH   or this?    export PATH=$PATH:~/opt/bin


I'm quite a newbie to designing.  Do you think this image has a good enough resolution for printing a 50 x 50 mm sticker?

(This question is meant to be a resource to direct others to given that this is a common question.)  Given the task of creating an image that will be printed at a certain size, what pixel dimensions and resolution should I be setting my file at?


We have a managed App to integrate with a third platform, so our app do a lot of API calls in Apex code. I reviewed the  and found the following item:     Maximum simultaneous requests to URLs with the same host for a callout request.      The host is defined by the unique subdomain for the URL—for example, www.mysite.com and extra.mysite.com are two different hosts. This limit is calculated across all orgs that access the same host. If this limit is exceeded, a CalloutException is thrown.   I am confused that the This limit is calculated across all orgs that access the same host, how to define across all orgs? If I have two customers A and B, will A's org simultaneous requests effect B?

Salesforce says      Maximum simultaneous requests to URLs with the same host for a callout   request is 20   Statement is very simple to read but it is not very clear as to what it means. Can anyone explain what this statement means and how can i reproduce this exception in my Sandbox?     Once more thing what is the difference between simultaneous and   concurrent? Are both same or different?


I have a multiple entry C-type Visa issued by Switzerland, valid until 2020, and period of stay 90 days. I've already been to Switzerland with that visa before, and stayed for around 20 days. Now I need to go for a short visit to Germany for 3 days. Can I use the same visa or I need to apply a new one?

My wife was just issued a multiple entry visa by France, which is good for one year.  Our first trip will be to France, the issuing country.  My question is: after we leave the EU and return, must future trips also start in France? Or may we go directly to (say) Greece from the US on a later visit?


, mentioned , in  - but I need instructions on how to use it!  Edit in Re: to comment/duplicate marks.. Unfortunately that script is the only one I know of, and it isn't for 13.10 (Assuming that version works on ARM procs).  THIS IS NOT A DUPLICATE, PLEASE GO BUY YOURSELVES SOME READING COMPREHENSION, KTHXBAI

I have installed Ubuntu 13.04 on my desktop (runs like a charm). Then I used Crouton to install Ubuntu 12. 04 on my chromebook samsung (ARM). It also works quite well.  Here comes my question. Can we have a true Ubuntu (preferably 13.04) on my ARM chromebook?  It seems that the Crouton/Ubuntu is not 100% the real thing.  The best option would be to have the full Ubuntu 13.04 and remove the Chrome OS.


My requirement is to create number of buttons equal to the json array count. I was successful in creating buttons dynamically in jquery. But the method in .ready function of jquery is not called for the click action. I have tried searching in SO. Found few solutions but nothing worked for me. I am very new to jquery. Please help...  my code: jQuery:  $(document).ready(function() {     currentQuestionNo = 0;     var questionsArray;     $.getJSON('http://localhost/Sample/JsonCreation.php', function(data)     {            questionsArray = data;         variable = 1;             //CREATE QUESTION BUTTONS DYNAMICALLY ** NOT WORKING         for (var question in questionsArray)         {             var button = $("<input>").attr("type", "button").attr("id", "questionButton").val(variable);              $('body').append(button);                          //Tried using .next here - but it dint work...             //$('body').append('<button id="questionButton">' + variable + '</button>');             variable++;         }         displayQuestionJS(questionsArray[currentQuestionNo], document);     });         $("button").click(function()     {          if ($(this).attr('id') == "nextQuestion")         {             currentQuestionNo = ++currentQuestionNo;         }         else if ($(this).attr('id') == "previousQuestion")         {             currentQuestionNo = --currentQuestionNo;         }          displayQuestionJS(questionsArray[currentQuestionNo], document);      });    function displayQuestionJS(currentQuestion, document)  {     document.getElementById('questionNumber').innerText  = currentQuestion.questionNumber;     document.getElementById('questionDescription').innerText  = currentQuestion.quesDesc;     $('label[for=optionA]').html(currentQuestion.optionA);     $('label[for=optionB]').html(currentQuestion.optionB);     $('label[for=optionC]').html(currentQuestion.optionC); }  HTML content <form method="post" name="formRadio">  . &nbsp;
 <input type="radio" id="optionA"> </input>
 <input type="radio" id="optionB"> </input>
 <input type="radio" id="optionC"> </input>
  <button id="previousQuestion">Previous Question</button> <button id="nextQuestion">Next Question</button>

  <input type="submit" id="submitButton" name="submitTest" value="Submit"></input> </form>   EDIT -- Sample .on Method code - Separate file: WORKING - THANKS A LOT       <button id="button">Static Button</button>

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


I would expect all players to have the same make of broom. Draco's bribe to get into the Slytherin team shouldn't be possible. Harry's broom should be the same as the others'.  Why was this allowed at school?

In the first Harry Potter book, Harry got Nimbus 2000 which was the fastest at the time. In the second book, Malfoy's father gave everyone in the Slytherin team Nimbus 2001.  A sports is a test of players, not their tools. Real World sports do allow players to bring their own tools, but there are fixed specification limiting that. Nobody's special tool can help a little bit in winning the game. For example, in Cricket history, once a batsman brought a wide bat covering entire pitch, so he couldn't be bowled. Seeing this loophole, a new rule was pushed to fix dimension of bat.  This brings one possibility about Quidditch: Maybe, a faster broom doesn't give a player advantage. But, I can turn down the possibility with various quotes from the book. Wherever better brooms are mentioned, you can see the owner (or his/her friends) boasting about advantages they would get in Quidditch. It is projected by the author, too. In the first book, McGonagall gave Harry Nimbus 2000 because it could be advantage to Gryffindor. In Mudblood and Murmurs chapter of the second book, when Slytherin team displayed their Nimbus 2001, all laugh at Gryfinndor team as if they had a big advantage in Quidditch now. Also, Gryfinndor team felt envy.  (Sorry for the regular language, but I don't have book at this time to give quote)  Why does Quidditch allow faster brooms which can give players advantage?


I used the code from  to write some java code in beamer that uses the Luebeck theme.   \documentclass[11pt]{beamer} \usepackage[utf8]{inputenc} \usepackage[T1]{fontenc} \usepackage{lmodern} \usepackage{graphicx} \usepackage{tikz} \usepackage{cprotect} \usepackage{listings} \usepackage{color} \usetikzlibrary{arrows.meta} \usetheme{Luebeck}  \definecolor{dkgreen}{rgb}{0,0.6,0} \definecolor{gray}{rgb}{0.5,0.5,0.5} \definecolor{mauve}{rgb}{0.58,0,0.82}  \lstset{frame=tb,     language=Java,     aboveskip=3mm,     belowskip=3mm,     showstringspaces=false,     columns=flexible,     basicstyle={\small\ttfamily},     numbers=none,     numberstyle=\tiny\color{gray},     keywordstyle=\color{blue},     commentstyle=\color{dkgreen},     stringstyle=\color{mauve},     breaklines=true,     breakatwhitespace=true,     tabsize=4 } \begin{document} %... \begin{frame}[fragile]         \frametitle{Java} \begin{lstlisting} // Hello.java import javax.swing.JApplet; import java.awt.Graphics;  public class Hello extends JApplet {     public void paintComponent(Graphics g) {         g.drawString("Hello, world!", 65, 95);     }     } \end{lstlisting} \end{frame} \end{document}   I get the output as below.    The lstlising is inside a fragile frame. Why are all my tabs replace with ^^I and how do I stop that from happening.

In beamer class, when i compile using LaTeX, the output pdf results perfectly the way i expect it to. But when i change it to XeLaTeX, in the lstlisting environment, every tab in the code results in a "^^I"-Placeholder (See output-pdf below). How do I fix this?   if( Bedingung ) {  ^^I//Code, der nur ausgefuehrt wird, wenn die Bedingung wahr ist   }  ^^I^^I   LaTeX-Code (Reduced to the minimum, one frame as an example):  \begin{document}     \begin{frame}[fragile]{if-Statements}         \begin{block}{Syntax}                \begin{lstlisting} if( Bedingung ) {     //Code, der nur ausgefuehrt wird, wenn die Bedingung wahr ist }                    \end{lstlisting}         \end{block}         \begin{block}{Logik}                 \begin{itemize}                  \item Alles innerhalb eines if-Blocks wird nur ausgeführt, wenn die Bedingung (in Klammern) wahr ist.             \end{itemize}         \end{block}     \end{frame} \end{document}


We have a web application on which users have profile pages that have a few details about the user, and then a list of blog posts that user has created. We're finding that in some circumstances Google will display a search result for one of these pages with the posts listed below like this:      In other circumstances, we have profile pages structured in exactly the same way but it is not displayed in the same way on Google search results. Like this:      I am trying to work out why the two pages are being displayed differently in the search results. The main difference is that they are on different domains, so my current thinking is that perhaps Google categorises domains in some way, and perhaps displays results differently because of that.  If anyone is able to tell me why this might be happening, or has any ideas, it would be much appreciated.     - the question does not answer my question about why two pages which have exactly the same markup and structure but just different content are displayed differently in search results.

My website is javatechig.com and is around 6 months old. I have used All-in-One SEO WordPress plugin for SEO tricks. Definitely after using SEO plugin, my website page view is increased, but still it is not giving one good site-link in Google Search.   I have followed the following steps:   Created sitemap.xml and submitted to Google Webmaster Tools Edited all posts with meta tags Header tags are carefully taken care   I want to make a sitelink similar to the attached image:


In the Ray Kurzweil's book How to create a mind is said that:      The mathematics of how Bernoulli's principle produces wing lift is still not yet fully settled among scientist [...]    What does this statement mean? I have always known that the Bernoulli equations were well known. There is something that I am missing?

I understand that the Bernoulli effect is a flawed explanation for the cause of lift, and does not cause much at all, but how much?   Is there any experimental data on the force caused by the Bernoulli effect? Maybe implicitly through data of the pressure difference between the top and underside of an aeroplane's wings. After that, I assume I could (crudely approximating the pressure to be acting perpendicularly to the flight direction) use $\Delta P A$ to work out the net force on the plane.    Perhaps there is another way to quantitatively analyse the extent to which the Bernoulli effect causes lift.  Edit: see  short cartoon (content similar to Mike Dunlavey's answer).


Okay, this is an animated show I watched years ago when I was a child, I have forgotten its name long ago and now I would like to see it again. I don't know whether the show was a TV series or a movie, but I watched it via DVD; I don't know the exact year when I watched the show, but I am absolutely sure it was before 2010, almost absolutely sure it was before 2008, the show was in 3D, it could be either CGI or stop motion, and I think it was more likely to be CGI. The show could either be of American origin or Japanese origin, the characters in the show were realistically proportional, the show was set in space, on a space station or a space ship or an asteroid, I am not sure which, though I am 99% sure it wasn't anywhere near planet Earth, and the characters (especially the protagonists) weren't humans, they were organic humanoid aliens, and part of some kind of military organization, and they were superhero-ish, though they used guns. The setting was either Science Fiction or Science Fantasy, and the scenes looked futuristic. Although I am not sure what the show was, I am sure what it wasn't. It wasn't Star Wars, Star Trek, Starship Troopers, Transformers, Gundam and Ultraman. Can anyone identify what was the show I had watched? I am sorry I can't provide any further details, it's been at least 12 years since, and I don't have photographic memory. If someone can help me, I would be very grateful.

I remember seeing this series back when I was in the early grades of primary school (prep to 3) so this would be between 1996 and 1999  from what I remember it was set in space and the cast was made up from people from these different worlds, one of the characters is from a fire attributed world and I get the impression he was small framed (I think).  at one point in the series this entity appears called the Beast Planet appears, the one scene I do remember is that this Beast Planet attacks the fire planet, the front of the beast planet opens up with this claw and grabs the fire planet from bellow and then the fire planet is slammed into the beast planet dooming the fire planet but I think the beast planet was unharmed.  I also seem to remember that the cast discover the other planets have engines which allows the remaining planets to escape from the Beast Planet rather than them being sitting ducks.  I remember that this beast planet, despite being called a beast is actually more machine. I began remembering this series after playing Galaxy Angel where I saw the  and it reminds me of this beast planet


I used QGIS 3 for clipping a satellite image using a shapefile.  The output raster gave a clipped image with dark background. How to fix this issue?

I would like to show on my map only the reddish pixels of my raster layer.  Said in another way: I would like to transform my white background into transparent background so I can see my other features.  I have the feeling this is possible using the custom transparence tab in the layer property.


I will be travelling to France and Switzerland with Family. Stay in both France and Switzerland is 5 days. As I am travelling through Lufthansa my port of entry and exit is Germany but I am not staying in Germany other than transit.  In this case, should I be applying for Visa through germany?

I'm planning to go to Germany on Sept 6-8, then Netherlands on Sept 8-11 and exit Switzerland on Sept 11-14.  My question is:  Which embassy do I need to apply for the Schengen visa? The number of days are the same for Netherlands and Switzerland, but I'm planning to apply in Netherlands since it will be my second point of entry.


Is there any reason to use/not use math mode for all numbers?  For example:     "The first few decimals of $\pi$ are $1$, $4$, $1$, $5$, $9$"?      "If you count in base $36$ every english word is a number: $h$ is $17$ and $hi$ would be $630$"      "There are $10$ types of people in the world..."   vs     "The first few decimals of $\pi$ are 1, 4, 1, 5, 9"?      "If you count in base $36$ every english word is a number: h is 17 and hi would be 630"      "There are 10 types of people in the world..."   In the first example, pi must obviously be in math mode or it won't display properly as the Greek letter pi. But the integers following that is not obviously one way or the other I think. I'd like to use math mode for the sake of consistency. Why would pi be more special than 1?  It the second example, I think it is obviously superior to use math mode for all numbers. If you don't, there is not really a way (for the compiler in particular but also readers) to distinguish what is a number and what are regular letters/words.  The third example I actually think is the hardest. If we look at it as a number, I think math mode makes most sense. But if we look at it as a word (I have a hard time forming this thought in word, but it feels like the number 10 is different from the meaning of the word "ten"), it kind of makes sense to treat it as a word (ergo not math mode).  To me it seems more natural to always use math mode when dealing with numbers, but it also seems like a pedantic thing no one in the right mind would do.

I typed up an assignment with a lot of numbers in LaTeX and turned it in to my adviser.  When he returned it to me with some corrections, one of which was a lot of $ around my numbers.  I understand that $ are necessary around some mathematical formulas, but I was just using numbers like -2 and 4.  I did not see any change in the font of the numbers when I added the $ either.  Since my adviser did not want to give me an explanation, what is the rationale?


I have some concerns about my code. What approach in JavaScript is preferential when conversion to the boolean value needed? Boolean(2) or !!2?

CPU Cycles, Memory Usage, Execution Time, etc.?  Added: Is there a quantitative way of testing performance in JavaScript besides just perception of how fast the code runs?


Suppose $A$ is an algebra of finite type over $\mathbb{Z}$ (i.e. a finitely generated ring). If $\mathfrak{m}$ is a maximal ideal of $A$, does it follow that $A/\mathfrak{m}$ is a finite field?

Suppose $k$ is a field that is finitely generated as a ${\mathbb Z}$-algebra.  (That is, $k$ is a quotient of ${\mathbb Z}[X_1,\dots,X_n]$ for some $n$). Does it follow that $k$ is finite?


I can not find the package to remove Google Play Music from my applications. It no longer functions. I am using 20.10 I have gone through the Applications window in the settings menu and clicked on the Open in Software button. It can not find the app in the store. I have searched for the app in the terminal. I have run a dpkg --list list and searche dall those results and found nothing. I am just learning about the terminal but I am not sure what to ask it to do, but I want to remove this app. Any suggestions?

Recently I seem to have "acquired" a second copy of Zoom. I cannot find it under the Software application and I cannot remove it via snap or apt. I have no idea where it came from, but it's a different Zoom UI than the version I installed, and doesn't work with my mic correctly. I can still uninstall "my" copy of the app (left in picture below). This may have happened when I upgraded to Ubuntu 20.04. How can I uninstall this unwanted application?  $ snap list | grep zoom zoom-client           5.3.472687.1012             106    latest/stable    ogra           -  $ apt list | grep zoom libnet-z3950-simple2zoom-perl/focal,focal 1.04-1build2 all libnet-z3950-zoom-perl/focal 1.30-2build1 amd64 node-d3-zoom/focal,focal 1.8.3-1 all ruby-zoom/focal 0.5.0-2 amd64 xzoom/focal 0.3-25 amd64 zoom-player/focal 1.1.5~dfsg-5 amd64 zoom/now 5.0.413237.0524 amd64 [residual-config]  $ grep -R Zoom /usr/share/applications ~/.local/share/applications /usr/share/applications/mimeinfo.cache:application/x-zoom=Zoom.desktop; /usr/share/applications/mimeinfo.cache:x-scheme-handler/callto=Zoom.desktop; /usr/share/applications/mimeinfo.cache:x-scheme-handler/tel=Zoom.desktop; /usr/share/applications/mimeinfo.cache:x-scheme-handler/zoommtg=Zoom.desktop; /usr/share/applications/mimeinfo.cache:x-scheme-handler/zoomphonecall=Zoom.desktop; /usr/share/applications/mimeinfo.cache:x-scheme-handler/zoomus=Zoom.desktop; /usr/share/applications/gnome-universal-access-panel.desktop:Keywords=Keyboard;Mouse;a11y;Accessibility;Contrast;Cursor;Sound;Zoom;Screen;Reader;big;high;large;text;font;size;AccessX;Sticky;Keys;Slow;Bounce;Mouse;Double;click;Delay;Speed;Assist;Repeat;Blink;visual;hearing;audio;typing; /usr/share/applications/gnome-keyboard-panel.desktop:Keywords=Shortcut;Workspace;Window;Resize;Zoom;Contrast;Input;Source;Lock;Volume; /usr/share/applications/Zoom.desktop:Name=Zoom /usr/share/applications/Zoom.desktop:Comment=Zoom Video Conference /usr/share/applications/Zoom.desktop:Icon=Zoom.png /usr/share/applications/Zoom.desktop:StartupWMClass=Zoom /usr/share/applications/Zoom.desktop:Name[en_US]=Zoom /home/adsteel/.local/share/applications/chrome-hmbjbjdpkobdjplfobhljndfdfdipjhg-Profile_2.desktop:Name=Zoom


I recently asked my  on Code Golf. In doing so, I was not prepared for the deluge of notifications.  In just one day, I have received over 25 notifications from that single question. Due to the competitive nature of Code Golf, I would prefer to wait and give others more time to answer before looking them over.  Can an option be provided to unsubscribe or temporarily mute notifications from a specific question?

Related:    Today, we had . This sort of sparked me into coming up with a new feature-request (Can't find a dupe, surprised).  Basically, we should have more control over what does and does not appear in the multicollider. This includes:   Muting comments and/or answers on a specific post. Muting comments from a specific user Ignoring all comments not addressed to you in a post of yours (I don't think this is that good, though--many times comments address both the OP and the other guy). Ignoring certain chat rooms The ability to make answers/comments on posts written by others to ping your multicollider.   Note that "Mute" could mean that it shows up in the inbox, but doesn't trigger the colorful glowing circle on the multicollider.    With the new "notifications" thing, there may be some scope in making certain notifications opt-in or opt-out (not all of these exist, but many would be useful in the notifications tab):   Notification of rejected edit Notification of  posts Notification of change to favorites Notification of certain badges Notification of edits Notification of edits to posts you have upvoted Notification of edits to posts you have downvoted (yes, should be separate)  - Notification of edits to posts you have closevoted


$R$ is a commutative ring with $1$ and $M_1,M_2$ are distinct maximal ideals of $R$. Then $R/M_1 \otimes _R R/M_2=0.$   Consider $f:R/M_1 \times R/M_2\to  R/M_1 \otimes _R R/M_2 $ defined by $f(r+M_1,s+M_2)=(r+M_1)\otimes (r+M_2)$  I can show this map is $R$-bilinear.  By the universal property of tensor products $f$ induces a homomorphism $\phi:R/M_1 \otimes _R R/M_2\to R/M_1\cap M_2=R/(1)=0$, but how can I show this map is an isomorphism?

Let $R$ be a commutative ring with identity and $I$ and $J$ be ideals in $R$.     Show that $R/I\otimes_R R/J\cong R/(I+J)$ as $R$-modules.   This is what I tried.  Define a map $f:R/I\times R/J\to R/(I+J)$ as $f(\bar r, \bar s)=rs+(I+J)$. This is a well-defined bilinear map.  By the universal property of tensor products, we get an $R$-linear map $F:R/I\otimes_R R/J\to R/(I+J)$ which sends $\bar r\otimes \bar s$ to $rs+(I+J)$.  This map is surjective.  So all we need to show is that the kernel of $F$ is $0$.  But I am unable to do this.


What would be the right icon for a toolbar button that triggers the following functionality in a spreadsheet application?   Toggle the visibility of all columns of the current sheet that currently don't contain any data (i.e. that are completely empty except for their column header).   Background: The user might have a row filter active that greatly reduces the number of rows shown. Usually, the filtered sheet view consists of just 30 or so rows (with the original data set containing hundreds of rows).   Often, the user filters in a way that the visible rows share the same empty columns. So after filtering, he might end up with a huge (50 columns+) sheet displaying 30 rows with most of the columns being completely empty.

I have a web page that has a list of columns of information.  All columns have names and then some of the columns have items in them.   I want to have an icon to represent   Hide all empty columns Showing all columns   All of the icons i see for hide look like "delete" so i want to see if there are any representations of "hide" icons that don't look like delete.  And for "show" the only thing i see is an eye graphic which doesn't seem very intuitive to me.  Does anyone have any recommendations for good "hide" and "show" icons?


A uniform rod is kept on a horizontal, smooth surface. A point mass moving with some velocity strikes the end of the rod and sticks to the end. Will the angular momentum be conserved about the "geometric" center of the rod (which is not the same as the COM of the system)?   My initial thinking was that the angular momentum should remain conserved about all points in the plane, as there is no external torque acting on the "rod+mass" system.But the answer says angular momentum will not be conserved about the center.  The only sort of explanation I can come up for this is that the rod will accelerate due to the impact , and thus we are looking at a point in a non-inertial frame.  So is the external torque provided by the "pseudo-force" that we need to account for?

In my physics problem I have a ball fired at a non fixed bar, which is moving at some velocity, causing them both to stick together and the bar-ball pair to rotate about the new center of mass. About which point(s) should I write my conservation of momentum equation? If I write it about the new com for both before and after, is it important that the bar is originally moving?


There are several topics on Stack Overflow which are closed due for different reasons, e.g. "not constructive", etc.   I think some of them would be important for lot of people, and because they are closed, they won't be up to date after a while, because science is always changing; there are new discoveries, new improvements in every year.  I know, that closing a topic is for good reasons, but I think it would be beneficial if the Stack Overflow community should consider (for example 100 votes for reopening would reopen the topic automatically), that a closed topic is worth reopening, or not.

To reopen a closed question,  must agree that the question is suitable for the site and cast votes to reopen the question. But:  How does one actually vote to reopen? Is there a reputation level that you must have before you can see this function? Or do I just leave a comment along the lines of, "I vote to reopen"? What happens if someone with less than 3000 reputation leaves a comment that they wish to vote to reopen? How can one draw attention to their closed questions? Is it done via a posting new question? Or do you edit the closed question?   Related:  For more information, see "" in the .


So, I was playing around with armatures, and at some point I had two armatures, which were both animated. Is there a way to join the bones together, so that they keep their animations?

I currently trying to join two rigged (and animated) models, which both has separate meshes, separate bones and separate animations. The first mesh is the horse while the second mesh is human:   So I am interested to join human model onto horse model to make a rider:   I think the best way would be to make horse as a parent and human as a child during the join process. In that case I would like that all horse animations (there are 3 of them - idle, walk and run) would remain as they are, while I can lose human animations, as I will need different ones for it. I was also thinking to make human root bone as a child of one horse back bones, that when horse moves up and down it would move entire human mesh together. It would be also good to keep the same weights that human bones would not start deforming horse mesh and vice versa.  I tried to use Ctrl+J by selecting various combinations between bones and meshes in object mode, however, I noticed that it messes up scaling and rotation of the child object. So I was wondering how it would be possible to properly join these models to create a rider?


I have a problem with my game in Java, It runs perfectly fine on windows computers but really laggy on mac (I've tested it on a few, all decent specs).  After looking in the console I get a nullPointerException error! I never noticed it before as it doesn't effect game play! I don't think this is the cause to it slowing down on macs but I'm not too sure.  So I guess I have two problems..  public void keyPressed(KeyEvent key) {     gsm.keyPressed(key.getKeyCode()); (line 120) }   Here is what the console spat out:  Exception in thread "AWT-EventQueue-0" java.lang.NullPointerException at KezPro.GamePanel.keyPressed(GamePanel.java:120) at java.awt.Component.processKeyEvent(Component.java:6372) at javax.swing.JComponent.processKeyEvent(JComponent.java:2809) at java.awt.Component.processEvent(Component.java:6191) at java.awt.Container.processEvent(Container.java:2084) at java.awt.Component.dispatchEventImpl(Component.java:4776) at java.awt.Container.dispatchEventImpl(Container.java:2142) at java.awt.Component.dispatchEvent(Component.java:4604) at java.awt.KeyboardFocusManager.redispatchEvent(KeyboardFocusManager.java:1856) at java.awt.DefaultKeyboardFocusManager.dispatchKeyEvent(DefaultKeyboardFocusManager.java:722) at java.awt.DefaultKeyboardFocusManager.preDispatchKeyEvent(DefaultKeyboardFocusManager.java:1000) at java.awt.DefaultKeyboardFocusManager.typeAheadAssertions(DefaultKeyboardFocusManager.java:865) at java.awt.DefaultKeyboardFocusManager.dispatchEvent(DefaultKeyboardFocusManager.java:686) at java.awt.Component.dispatchEventImpl(Component.java:4648) at java.awt.Container.dispatchEventImpl(Container.java:2142) at java.awt.Window.dispatchEventImpl(Window.java:2492) at java.awt.Component.dispatchEvent(Component.java:4604) at java.awt.EventQueue.dispatchEventImpl(EventQueue.java:717) at java.awt.EventQueue.access$400(EventQueue.java:82) at java.awt.EventQueue$2.run(EventQueue.java:676) at java.awt.EventQueue$2.run(EventQueue.java:674) at java.security.AccessController.doPrivileged(Native Method) at java.security.AccessControlContext$1.doIntersectionPrivilege(AccessControlContext.java:86) at java.security.AccessControlContext$1.doIntersectionPrivilege(AccessControlContext.java:97) at java.awt.EventQueue$3.run(EventQueue.java:690) at java.awt.EventQueue$3.run(EventQueue.java:688) at java.security.AccessController.doPrivileged(Native Method) at java.security.AccessControlContext$1.doIntersectionPrivilege(AccessControlContext.java:86) at java.awt.EventQueue.dispatchEvent(EventQueue.java:687) at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:296) at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:211) at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:201) at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:196) at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:188) at java.awt.EventDispatchThread.run(EventDispatchThread.java:122)

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 tried to install ubuntu alongside with Windows 8, but for some reason, it just deleted the W8 installation. But now, i want windows back, because Wine cant emulate all programs, which is, of course, to be expected. BUT: Even though i created the USB key with WinUSB () my computer won't boot from it! I have changed the boot order, tried to use boot menu, but i am all out of ideas :( The USB key is a Kingston DataTraveller 32GB USB3, formatted as NTFS and all the windows files on it (Note, i am trying to install Windows 7), so i don't understand where it went wrong. I hope you guys/girls have some ideas :)  Jonas Strand

I tried to use the usb-creator.exe from Ubuntu 10.10 desktop i386 ISO image and it does create an USB stick that doesn't boot. When I try to boot from it I get:     Operating System not found.   I try to do this from Windows 7 x64. I'm not looking to create a live Ubuntu media, only an installation USB disk.  I repeated the process several times and I even tried to reformat the USB drive (FAT32), no success yet.  The USB stick is a 8GB one.


I would like labeling as follows:   It does not get proper labeling on y-axis when I am plotting data from CSV file in Latex. Here is the code :    \documentclass{standalone} \usepackage{tikz,pgfplots} \usepackage{filecontents} \pgfplotsset{compat=1.8}   \begin{document} \pgfkeys{/pgf/number format/.cd,1000 sep={\,}} \begin{tikzpicture} \begin{axis}[  %restrict x to domain=1:4, restrict y to domain=7:8, %ymax=8,ymin=7 xtick={1,2,3,4}, %ytick={7.90,7.91,...,7.99,8}, xlabel=Shares, ylabel=Entropy]   \addplot[color=red,mark=*, mark size=1.5pt] table[x=Share_No., y=Entropy_r, col sep=tab]{data.csv}; \addplot[color=green,mark=square*, mark size=1.5pt] table[x=Share_No., y=Entropy_g, col sep=tab]{data.csv}; \addplot[color=blue,mark=triangle*, mark size=1.5pt] table[x=Share_No., y=Entropy_b, col sep=tab]{data.csv}; \legend{red,green, blue}  \end{axis}   \end{tikzpicture} \end{document}   and the CSV file :    Share_No.   Entropy_r   Entropy_g   Entropy_b 1   7.9981486429    7.99831760161   7.99844751811 2   7.99870797699   7.99858499663   7.99867850346 3   7.99883018839   7.99864575932   7.99835839694 4   7.99851352793   7.99834080804   7.99864899695   It produces the following graph:      How can I fix this?  Updated: The answer in the given link is not working for me.  Here are the modified codes:    \documentclass{standalone} \usepackage{tikz,pgfplots} \usepackage{filecontents} \pgfplotsset{compat=1.8}   \begin{document} \pgfkeys{/pgf/number format/.cd,1000 sep={\,}} \begin{tikzpicture} \begin{axis}[      y tick label style={     /pgf/number format/.cd,     fixed,     fixed zerofill,     precision=1,     /tikz/.cd },  %restrict x to domain=1:4, %restrict y to domain=7:8, %ymax=8,ymin=7 xtick={1,2,3,4}, %ytick={7.90,7.91,...,7.99,8}, xlabel=Shares, ylabel=Entropy]  \addplot[color=red,mark=*, mark size=1.5pt] table[x=Share_No., y=Entropy_r, col sep=tab]{data.csv}; \addplot[color=green,mark=square*, mark size=1.5pt] table[x=Share_No., y=Entropy_g, col sep=tab]{data.csv}; \addplot[color=blue,mark=triangle*, mark size=1.5pt] table[x=Share_No., y=Entropy_b, col sep=tab]{data.csv}; \legend{red,green, blue}  \end{axis}   \end{tikzpicture} \end{document}

How can I force pgfplots to draw my axis ticks labels consistently? I mean instead of 0 a 0.0, instead of 1 a 1.0 in the below image.        EDIT: Code    \documentclass[a4paper,10pt]{scrartcl} \usepackage[utf8]{inputenc} \usepackage{graphicx} \usepackage{pgfplots} \usepackage{pgfplotstable} \usepackage{filecontents} \usepackage{siunitx}  \pgfplotsset{ compat=1.7, every axis/.append style={ line width=1.25pt, tick style={line width=1.25pt, color=black, line cap=round} } }  \begin{document}  \begin{tikzpicture} \begin{axis}[   enlarge x limits=0.05,   enlarge y limits=0.05,   try min ticks=4,   max space between ticks=50pt,   y tick label style={     /pgf/number format/.cd,     fixed,     fixed zerofill,     precision=1   },   x tick label style={     /pgf/number format/.cd,     fixed,     fixed zerofill,     precision=2   } ] \addplot[red] table[x index=1,y index=7] {dataA.dat}; \end{axis} \end{tikzpicture}  \end{document}   I can't attach the data file, so here's a .


A* and Dijkstra's pathfinding algorithms work by navigating a node map. In a tile-based 2D environment, these nodes could easily be inferred to be the literal x,y positions of the map.  For example, the agent is at (0,0), an obstacle is at (0,1), and the agent wants to go to (0,2).  However, in a 2D environment where locations are represented using floating point variables float x, float y, agents and obstacles can exist between the traditional style nodes (0,0) and (0,1).  How do you create a node map from such an environment?

I'm not sure if this is even  path-finding. All I have is a 3D map that has hills, etc. I'd like the enemy to flock an object, but also walk around other objects. These blocking objects may be added after the path is calculated, which would cause a re-calculation of the path.  What algorithm am I looking at here?


I have a webpage taking a new user name & password as input. For scripting, I am using AngularJS.  <div class="form-group">  <input ng-model="prc.userName" placeholder="User Name" type="text" class="form-control" autocomplete="nope" required autofocus /> </div>   This input box always gets auto-filled, I don't want it to get auto-filled.  Question reviewed prior:   // These attributes do not work autocomplete="off" autocomplete="false"   My chrome version: Version 73.0.3683.103 (Official Build) (64-bit)  How can I do that?

How do you disable autocomplete in the major browsers for a specific input (or form field)?


I got the following dictionary:      freelancers = {'name': 'freelancing Shop', 'brian': 70, 'black knight': 20,                     'biccus diccus': 100, 'grim reaper': 500, 'minstrel': -15}   I want my for statement to loop trough all the dictionary..and if a value that contains the word 'shop' is found. Printing it. Is there any way to do it??.   this is clearly not working, values could be string, int, etc.  for key, value in freelancers.items():     if 'Shop' in value:         print(f"Welcome to {value}")

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


I created a map and I want to sort it by the value but I need to give the output as a list of the strings only. I think I can sort the map by extending comparable and then add every sorted key to a list but I'm not sure it is the best way. Any ideas?  //code is not finished yet// public List<String> search(String prefix) {     Map <String, Integer> suitable_sites = new LinkedHashMap<>() ;     List<String> sorted_list = new ArrayList<>();     for (Map.Entry<String, Site<String>> site :index.entrySet()) {         Map <String, Integer> words = site.getValue().getWords() ;         int counter =0 ;         for (String word : words.keySet()) {             if (word.startsWith(prefix))                 counter++;         }         int weight = counter / site.getValue().getAmmount();         if (weight == 0 )             continue;         suitable_sites.put(site.getKey(), weight);     }     return  null; }

I am relatively new to Java, and often find that I need to sort a Map<Key, Value> on the values.  Since the values are not unique, I find myself converting the keySet into an array, and sorting that array through array sort with a custom comparator that sorts on the value associated with the key.  Is there an easier way?


Any algorithm or theorem to decide whether two functions that are polynomials,rationals and analytic over $\mathbb{N}$ or $\mathbb{Q}$ or $\mathbb{R}$ or $\mathbb{C}$ are equivalent ?

Let's say you have a few expressions like the following:  $$\begin{array}((x+17)^2 \\ x^2 + 34x + 289 \end{array} \\ 288 + \frac{x^2}{2} + \frac{x^2}{2} + 34x + 1 \\ [...] $$  You get the idea: there's an infinite number of ways of representing the same expression. The challenge is that my application is validating answers to math problems, input by math students practicing a certain concept. I'd like to make sure that whenever they submit an answer, the checker is completely insensitive to the issues of ordering, simplification, formatting etc. which would be plain frustrating. I'd also ideally like to support more than one variable such as x, y, z in the same expression.  What's a reliable way to check that two expressions are the same? The most brute force way I can think of would be to just plug a number into each variable of each expression and see what the result is.  I have a hunch however that there might be ways of getting false positives this way. That, and I might be either missing something really obvious about this, or there might be a better way of doing the comparison.  Would love to hear what you think.


I want to isolate the on-board stlink, and use an external ST-Link/v2 to program/flash the board. I have a 20-pin JTAG connector. This is just a temporary, proof-of-concept project.   I have removed the jumpers from CN3 pins as instructed here:     I cannot comment on that post because I do not have enough rep points.  I connected:   (JTAG) SWDIO -> PA13  (JTAG) SWCLK -> PA14  (JTAG) GND -> GND  (JTAG) VAPP -> 3V/VDD, as instructed  Also, the post says not to connect the USB. I am not sure which USB this is referring to. An external ST-Link/v2 needs to be powered by an USB, and so does the board. I have tried this: 1)connect only the ST-Link/v2 usb, but this is not enough to power the board. 2)connect only the board usb, but this does not power ST-Link/v2.  I am a beginner and I am using the Linux terminal. I have successfully flashed an example "blinky" program to the board. I would be very grateful if someone could assist me. Thank you.

I have a  board and a  programmer.  I want to use my own ST-Link (not the embedded one) for programming and debugging the board.  How should I connect the external ST-Link to the board ?


Is it possible to use If/Then statements with dynamic text in Data Driven pages labeling? I have been trying a bunch of different ways, but it has not been working, and I am fairly new at writing scripts.  If I was to write out my statement in a label expression, my example would be:  Function FindLabel([Land_Owner_Zone1], [Land_Owner_Zone2], [Zone]) If [zone] = "Zone 1" Then Findlabel = [Land_Owner_Zone1] & vbnewline & [Zone] Else Findlabel = [Land_Owner_Zone2] & vbnewline & [Zone] End If End Function   I am unsure how to write this in dynamic text format for data driven pages.

Is it posssible to perform any math on ESRI ArcMap dynamic text?  For example I have the area of a SDE park layer's SHAPE.AREA, but it is in m2 because the layer is in NAD_1983_UTM_Zone_17N.  I want to show the area in hectares (m2 / 10000).  How do I do this?  Is it possible to add two fields together and display it in dynamic text?


I'm reviewing the basic number theory from my undergrad program (so I can jump back into abstract algebra well enough), and I've come across this problem in the section regarding the Fundamental Theorem of Arithmetic. I'm sure the answer is sitting right in front of my face, but I can't figure out if I'm having an issue of not seeing the last step or going down the wrong path in the first place. Any help is appreciated; thanks!  Prove: Let $a,p\in\mathbb{N}$ with $p$ prime. If $p^4|a^3$, then $p^2|a$.  Proof (so far): Let $a,p\in\mathbb{N}$ be given, with $p$ prime, such that $p^4|a^3$. Then $p|a^3$, so by Euclid's Lemma, $p|a$, and thus $a=pn$ for some $n\in\mathbb{Z}$. Now, for some $k\in\mathbb{Z}$, $p^4k=a^3=ap^2n^2$, so $p^2\frac{k}{n^2}=a$. (Here's where I'm stuck; it would be great if I knew $n^2|k$)

Prove or disprove: If $a \in \mathbb{Z}$, $a > 0$, and $p$ is a prime such that $p^4 \mid a^3$, then $p^2 \mid a$.  I looked at the answers to the duplicate questions and I'm still confused. I can't even think of any counterexamples. Any tips on where to start?


I have a Backbone App where I fetch Twitter tweets through an API which returns the result as string. What I need is to make the http in the string clickable. How can I achieve this?  Here is the text string:   Who does John wish he could have sung with over the span of his career? See the video answer here! http://t.co/pbPXaDkGEJ    and I want it to be like   Who does John wish he could have sung with over the span of his career? See the video answer here!  click here   I tried to do something like:  function replaceURLWithHTMLLinks(text) {    var exp = /(\b(https?|ftp|file):\/\/[-A-Z0-9+&@#\/%?=~_|!:,.;]*[-A-Z0-9+&@#\/%=~_|])/ig;    return text.replace(exp,"$1");  }   but that didnt work...  [UPDATE]  Ok, I'm gonna add my Backbone View:  function (App, Backbone) {      var ArtistTwitter = App.module();      ArtistTwitter.View = Backbone.View.extend({         tagName: 'ul',         className: 'actweets',         template: 'artistTwitter',         initialize: function() {             this.listenTo(this.collection, 'all', this.render);         },         serialize: function() {             return this.collection ? this.collection.toJSON() : [];         }     });     ArtistTwitter.ArtistTwitterCollection = Backbone.Collection.extend({         url: function() {             return '/myproject/index.php/api/social_feeds/fetchNewTweet/' + this.artist_id;         }     });      return ArtistTwitter; }   I tried to add the above mentioned replacement code inside an afterRender-function but that didnt work...  Any suggestion is welcome...

I am using the function below to match URLs inside a given text and replace them for HTML links. The regular expression is working great, but currently I am only replacing the first match.  How I can replace all the URL? I guess I should be using the exec command, but I did not really figure how to do it.  function replaceURLWithHTMLLinks(text) {     var exp = /(\b(https?|ftp|file):\/\/[-A-Z0-9+&@#\/%?=~_|!:,.;]*[-A-Z0-9+&@#\/%=~_|])/i;     return text.replace(exp,"$1");  }


I have encountered a weird problem (in my eyes) to do with bibliographys in included chapters and the structure of a document and I just cannot find out whats the cause...   In the final document, I want to include a table of contents structured as follows:    I would like NOT to have the page for stating "PART 1 - Introduction", which I want to exclude using this command:   \renewcommand{\part}[1]{\addcontentsline{toc}{part}{#1}}   However, if I include this into my document, I end up with the following TOC:    --> The "Introduction" part moves to the bottom of the TOC  I have already figured out using a MWE, that it has something to do with including the bibliography inside a chapter that I am including, as a MWE with the bibliography in the main file was fine as well as including a chapter without a bibliography was fine - but the combination of those somehow triggers this?  This works:  \documentclass{book}  \usepackage{lipsum} \renewcommand{\part}[1]{\addcontentsline{toc}{part}{#1}} %removes pages with part headers  \begin{document}  \tableofcontents \cleardoublepage  \part{Introduction} %\include{MWE_Chapter} \chapter{Wabbadabbadupdup} % (fold) This is just a test and a citation \citep{Carmichael2008} -   \section{Hey ho Lets go} \lipsum  \bibliographystyle{jneurosci} %apalike, abbrv \bibliography{library}  \end{document}   This doesn't:  \documentclass{book}  \usepackage{lipsum} \renewcommand{\part}[1]{\addcontentsline{toc}{part}{#1}} %removes pages with part headers  \begin{document}  \tableofcontents \cleardoublepage  \part{Introduction} \include{MWE_Chapter}  \end{document}   with MWE_Chapter being:  \chapter{Wabbadabbadupdup} % (fold) This is just a test and a citation \citep{Carmichael2008} -   \section{Hey ho Lets go} \lipsum  \bibliographystyle{jneurosci} %apalike, abbrv \bibliography{library}   I would really like to know what causes this behavior and if someone can reproduce it? Or if there is another possibility to remove the pages created by the \part syntax without changing the TOC! Thanks!  The same by the way happens if I use   \addcontentsline{toc}{part}{<Header of the part>}    instead of the renewcommand to remove the part page

My LaTeX document is acting strangely. Here is a simplified version of it:  \documentclass{article}  \begin{document}  \tableofcontents \newpage  \addcontentsline{toc}{part}{A Part of My Document} \include{includedfile}  \end{document}   And in includedfile.tex:  \section{My Section Title} Quack.   Clearly, in the table of contents, the heading for the part should precede the one for the section, but it doesn't! What's wrong?


I came across the following problem while self studying:  Let  \begin{equation} A =  \begin{bmatrix} 2 & 1 & 3 & 7 & 5\\ 3 & 8 & 7 & 9 & 8\\ 3 & 4 & 1 & 6 & 2\\ 4 & 0 & 2 & 2 & 3\\ 7 & 9 & 1 & 5 & 4\\ \end{bmatrix} \end{equation}  Use the fact that 21375, 38798, 34162, 40223, and 79154 are divisible by 19 to show, without evaluating, that $\det[A]$ is divisible by 19.  I noticed that each of these numbers are the entries in the rows of A, but I don't see how that helps me.

Let $n\in\mathbb N$ and let $a_1,\ldots,a_n$ be natural numbers smaller than $10^n$. Write each $a_k$ in base $10$ and add $0$'s to the left of each decimal expansion, if needed, so that each $a_k$ is written with $n$ digits. Consider the matrix such that the entries of the $k$th row are the digits of $a_k$ (written in the same order). Let $d\in\mathbb N$ be such that $d$ divides each $a_k$. Prove that $d\mid\det A$.   For instance, suppose that $n=4$ and that your numbers are $3876$, $2784$, $684$, and $8388$, each of which is a multiple of $12$. Then$$A=\begin{bmatrix}3 & 8 & 7 & 6 \\  2 & 7 & 8 & 4 \\ 0 & 6 & 8 & 4 \\  8 & 3 & 8 & 8\end{bmatrix}$$and $\det A=-360$, which is, in fact, a multiple of $12$.  I learned about this problem yesterday. I found it quite cute and I decided to share it with all of you.  Note: I know how to prove it.


Ever since I gained 3000 rep on SO, I've noticed that the  has increased consistently. It must have been 2 or 3 months ago that I first got rep to start reviewing questions and I've noticed that number creep up from 50k to now almost 83k.  It's clear the number of questions pending more close votes is creeping up and there's literally thousands of questions that will never get touched but remain on the list. Every single other section of reviewable questions/answers stays low consistently.  How do we tackle the endless in-stream of questions with close votes?   I understand that it's common for a close vote or two to get slapped on a question and it gets left that way forever. Should we remove stale close votes that never ended up in an actual closure? Is SO prioritizing newer questions over old ones when you actually start reviewing those questions?  Maybe this isn't even an issue and I'm not seeing it. Let me know what your thoughts are!

Today, the size of the close-votes queue is 55k questions and growing. Is that a problem?   Which action could be taken to clean it up? It seems to be growing faster than Stack Overflow members are capable to handle it.


I have a data in my mysql database's table which is Biñan. However, when I try to retrieve it using php, it showed as Bi�an in my dropdown list.   Here is my sample code:  <?php    $query = "SELECT * from municipality";    $res = mysqli_query($conn,$query);    while($row = mysqli_fetch_assoc($res))    {      echo "<option value='".$row['m_id']."'>".$row['m_name']."</option>";    } ?>   But when I manually echo/insert the character ñ in php/mysql it displayed as is. I have also set the charset to UTF-8.  PROBLEM SOLVED!: I just have to replace the ñ with Ã± in my database's table. So it shows ñ in my website.

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


I would like to create my list of figures having a small miniature of the figure in the margin. Now my list of figures is like this . And my will is to insert a small version of the picture next to the counter, in the margin. This has been discussed , however, I want to add thumbnail in margin, not just before caption in text

To be honest, I'm not sure if I really want this because I can't imagine how exactly it would look. But maybe someone is interested in this, too, or even has already written code to achieve this: it might be practical or interesting to have small thumbnail previews of a figure in the list of figures next to the caption.  This has already been briefly discussed here  but without any result so if anybody wants to give it a shot or has already done so: yay! :)    See  for an example image of how this might look.


I do know that a Windows 7 Home premium does not have the "join to a domain" feature. But shouldn't they be able to access a shared drive on a domain?, as I've seen some can access.  However, I've been having difficulties to fix such a workstation which can ping the destination server but does not offer username/password prompt to access the said server shares. I've tried the registry editing method to overcome this issue; which didn't work too.  Any help or advise on this will be great.

The company that I work for continuously hires new people, and I'm the one who has to go and purchase new computers.  The majority of them, if not all, come pre-installed with Windows Home editions.  I'm noticing that the Windows 7/8 Home editions are unable to connect to domains.  I'm having to buy the upgrades to the Pro editions.  I'm trying to understand as to why the Home edition of the OS is unable to connect to domains?


Just rewriting this post so it's more clear.  I'm unable to get back to Windows after I burned Ubuntu to my USB Drive after using a program called "Rufus".  Now, when I attempt to boot Windows, even after I took out my USB Drive, it will still boot to Ubuntu.  I'm not sure about what to do to get back to Windows, and I'm worried because I had important photos and videos there as well.  When I attempt to get back to it, it says "No partitions detected", so this may be the problem.  EDIT #2 : The problem may be that I didn't select the "Try Ubuntu without installing" option, but rather the second one (I forget the name...).

I am not sure if this question is appropriate to be posted here but I have really no idea and I really need to fix this problem ASAP and I am so frustrated right now. I was dual booting windows 8.1 with ubuntu and after a successful installation in which both OSes boot fine, I installed gnome on Ubuntu and I could not get Ubuntu booting again, so I decided to reinstall Ubuntu but I didn't know that the reinstall and wipe data option will remove the Windows drive. Now I am left with Ubuntu but I still need Windows as my primary OS, I have backup up a system image of Windows 8.1 and my question is how to restore from that, loosing Ubuntu isn't an issue, any ideas would be greatly appreciated


I have installed the latest version of IntelliJ 2019.3 community edition on my laptop which is running Ubuntu V19.04. Recently IntelliJ developed a problem where a normal way to start it was not working at all, so i am launching it by going into its /bin folder and write ./idea/sh to start the application.  My question here is how can I make IntelliJ start without going to its directory and type a command to run it everytime?

In older versions it was easy to create a launcher on my desktop. All I had to do is right click on my desktop and select the "create launcher" option.  How can I create such launchers now?


In C++, I would like to compute the number of bits that is 1 in a uint64_t  # A few examples in uint8_t: 0b00000000  ==> 0 0b01000001  ==> 2 0b00110101  ==> 4 0b11111111  ==> 8   I need to perform a lot  (say millions) of such operations, is there a fast way to do so (maybe with some pre-processing)?  One possibility I can think of is to create a lookup table for every N bit (say N=8), and perform 64/N lookups for a uint64_t. Is there a better solution for this? If I decide to go for the above approach, how should I set N? (To my understanding even ignoring all pre-processing computation, it is not the case that the larger N is, the better, Because the look-up speed actually depends on whether the look-up table can fit in cache?)  Thanks a lot!

8 bits representing the number 7 look like this:  00000111   Three bits are set.     What are algorithms to determine the number of set bits in a 32-bit integer?


I have a 500 gig drive as well as an 80 gig drive. I would like to clone the 500 gig over to the 80 gig and I think it might work because there is not 80 gigs of data on the 500 gig drive.  Will this work?

In a few hours I'll have a new 500GB Sony laptop, filled with the usual Sony rubbish which I'll promptly be replacing with Ubuntu or Crunchbang or something. However, first I want to make a full clone of the drive (including recovery partitions), should I wish to return it to Sony or sell it on in its factory state.  The problem is that the only backup drives I have are less than 500GB - the biggest I have is 250GB or so! So I need to backup and compress on-the-fly.  What's the best way to do this? Presumably dd piped into gzip would do the trick, or does anyone have any other suggestions to accomplish this?


this question is by no means a new question, however previous questions have been unable to exactly answer my question. I'm attempting to obtain analytical results and then plot the results of a central field system when given the initial position and velocity of the particle. I know this is just an Initial Value Problem and I have already programmed a Runge-Kutta method, which I would hope to use, or even the scipy.linalg.solve_ivp. However, I don't know how to start properly. For my RK method, I can apply a (2,2) ndarray to my system then iterate, but I don't know what this matrix would take the form of, i.e. what would be the elements general form look like?

How can I use the Runge Kutta 4 method to solve orbits of Newtonian Mechanics, with position vector $\mathbf x$, velocity vector $\mathbf v$ and acceleration vector $\mathbf a$? Do I still have to calculate the acceleration by combining the forces?


In the proof of the the lemma   suppose $G$ is a finite abelian $p$-group, and let $C$ a cyclic subgroup of maximal order, then $G=C\oplus H$ for some subgroup $H$  at ,   They say that since $H\cap(C+K)= K$, we have $H\cap C=\{e\}$. But how do they have that  $H\cap(C+K)= K$? Can someone prove that please is because I don't see why is that true with the arguments presented in that proof. thanks a lot in advance :)   I am sorry for this but my doubt was in the part that I pst here and in the other question the answer was to other thing :)

Well, in the proof of the following lemma suppose $G$ is a finite abelian $p$-group, and let $C$ a cyclic subgroup of maximal order, then $G=C\oplus H$ for some subgroup $H$ at , They say that since $H\cap(C+K)= K$, we have $H\cap C=\{e\}$. But how do they have that this part $H\cap(C+K)= K$? Can someone prove that please is because I don't see why is that true with the arguments presented in that proof. I have the following attempt : We know that $G/K=(C+K)/K \cong H' \Rightarrow H \cap (C+K)=K$ If there is $x \in H \cap C, x \neq e,$ then $H \cap (C + K) = K \Rightarrow x \in K.$ But by your assumption $C\cap K = \{e\}$ more precisely : I want to prove (convincing myself), why is this rght. In the proof of the lemma suppose $G$ is a finite abelian $p$-group, and let $C$ a cyclic subgroup of maximal order, then $G=C\oplus H$ for some subgroup $H$ at  they have that since $H\cap(C+K)= K$, we have $H\cap C=\{e\}$. But how do they have the part of $H\cap(C+K)= K$? is because they say that $H'$ is the preimage of a certain map, then they can do the following: $G/K= (C+K)/K \oplus H/K$ but I do not know if that is enough to justificate that step, or how can they have the conclusion that  $H\cap(C+K)= K$,and well the part that $H\cap C=\{e\}$ is obvious from here, and in the proof of the same lemma they say that because $K$ has prime order then $K\cap C=\{e\}$,  is that the only reason? Can someone prove those things please is because I don't see why is that true with the arguments presented in that proof. Thanks in advance. I am back in the discussion and I have edited my post to be clearler :)


I've been working on a project for a client in which I'm building a city so that I can render it and use the render as reference for drawing. However, there's this bug which I haven't encountered in any other Blender project so far: The surfaces look hatched and glitchy. It's evident when you look at the mountains or the buildings' angle with the floor in pictures 1 and 2, in both solid, material preview and eevee render mode. I don't know what is causing this. Magically, the effect seems to be completely gone when I use the orthogonal view. When I press 0 to see the camera view, the hatched look can only be seen at the mountains. With cycles renderer it seems to be all right (but I don't want to break my computer by making it render with cycles all the time when I simply want to edit the scene). This issue is very annoying, so I've been wondering if somebody else has been having the same problem and if there's a way to fix it.

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.


After installation Ubuntu 20.04 on my new laptop Lenovo-Legion-5P, I can't reboot/restart the system. I'm getting in a black screen. CPU: intel core i7-10875H CPU 2.30GHz GPU: nvidia GeForce RTX 2060 Bios Version: EFCN38WW Tried this: Boot Mode: Legasy Support --> UEFI PTT: Enable --> Disable This way doesn't work for me. Any ideas? Thank you

I am trying to boot Ubuntu on my computer.  When I boot Ubuntu, it boots to a black screen.  How can I fix this? Table of Contents:


I was trying to create a painting effect (a simple brush rolled over a surface changes the color of the surface to that of the brush) with dynamic paint. So, I added a canvas and a brush, kept the Dynamic Paint advanced surface type to Paint, and use the object's material to paint. But as you can see in the picture the paint effect is hardly visible, in fact its not even sure whether it's a small reflection from the shader or actually the paint effect. So, how do you make the paint effect distinct? Any suggestion is appreciated  .Thanks

To make it simple: I have a project using dynamic paint. In the viewport the dynamic paint works as it's supposed to work. But when rendering it the dynamic paint doesn't show/gets rendered.   I really have no idea what I did wrong so I'm hoping that someone of you knows how to fix this.


I am working on a simple database using Microsoft Access 2013 with a MySQL backend via ODBC. I want to include some very basic form of user tracking, and I plan on doing this by prompting users for a username and password upon opening the database and comparing these to values in MySQL. Security is NOT a big issue -- I just want something that works and ideally doesn't rely on storing passwords in plaintext. Is there some easy way in Access to calculate the hash of a string so that I can avoid relying on plaintext storage of passwords?

I need a function written in Excel VBA that will hash passwords using a standard algorithm such as SHA-1.  Something with a simple interface like:  Public Function CreateHash(Value As String) As String ... End Function   The function needs to work on an XP workstation with Excel 2003 installed, but otherwise must use no third party components.  It can reference and use DLLs that are available with XP, such as CryptoAPI.    Does anyone know of a sample to achieve this hashing functionality?


Does Android have restore points that can be accessed via fastboot? In Windows7 (support ended February 2020) restore points are created so the OS can revert back to last known state should anything go wrong. This revision includes settings, software, browser history, etc. This handy feature has helped me several times. Does Android have such a utility/feature where by any means (fastboot or adb) it can be rolled back to last known state? Kindly read more to understand the full situation. My phone is stuck in fastboot. I have been doing research on how to get it out of this. The phone runs Android Go. Usually the OS updates and completes without any issues, but this time during an update the battery died and upon power up it got stuck in Fastboot mode. I understand both Fastboot and ADB have commands of their own that can be used to interact with Android OS via USB connection. I have a question that my research has NOT answered. Before I run any commands in this mode (fastboot) I want to know, is there a way to restore the device to its last stable state (ie before the failed OS update)?

The internal storage of each Android device is separated into partitions such as system and boot. Most devices have only a single copy of each partition, but devices that support seamless updates have two copies of certain partitions—slot A and slot B, hence A/B—so that one copy of the partition lies dormant while the other is in active use. Because each partition is a copy, they can be used interchangeably to boot into Android. This also means that you can update one partition in the background and then swap to it when you reboot—thus your update is seamless!  I need to know more about this for a stock unrooted device:   After OTA system update, does the device install OS to both partitions? Or  install to only one partition.  whether the device continues to same(current) android version until reboot manually?(after installing version update). Or whether it updates current to latest version overnight. When normal reboot(not after update), how can a user identify whether device is booted to which slot (A/B)? Else, will the device continues to current slot on normal reboot(for example if it is A).  If any one slot got corrupted, Is it possible to use other slot only.


I don't use the Music, Documents, Pictures, Video, and Trash folders often enough to warrant them an honorary place on the sidebar of Ubuntu's 13.04 default file manager "Files".    I would like to remove them, but the "Remove" item on the context menu is grayed out. Since Linux distros tend to be configurable I'm guessing there is a way around this.  The Gear menu doesn't seem to have any options to do this:    The Bookmarks menu looked helpful, but it still made no changes.      (This is after I removed all the Bookmarks I wasn't interested in.)  I have also tried the suggestion from  and commented out lines I don't want from user-dirs.dirs, but still no luck:  $ vim ~/.config/user-dirs.dirs <edits> $ xdg-user-dirs-gtk-update   How do you remove these default items from the sidebar?

I want to remove Videos and Music from the left side panel. But, I can't seem to find the option to do so. How do you do that?


When I change directory to //, it seems to put me in a special directory that is very similar to but slightly different to /. However, trying to add any further slashes (///) simply drops me in /.  $ cd /    ;pwd / $ cd //   ;pwd // $ cd ///  ;pwd / $ cd //// ;pwd /   It seems that // is somehow special, even though it has the same directories and everything, it's still a different string returned by pwd. Why is this? Why can my working directory be // but not ///?

In unix/linux, any number of consecutive forwardslashes in a path is generally equivalent to a single forwardslash. eg.  $ cd /home/shum $ pwd /home/shum $ cd /home//shum $ pwd /home/shum $ cd /home///shum $ pwd /home/shum   Yet for some reason two forwardslashes at the beginning of an absolute path is treated specially. eg.  $ cd ////home $ pwd /home $ cd /// $ pwd / $ cd // $ pwd // $ cd home//shum $ pwd //home/shum   Any other number of consecutive forwardslashes anywhere else in a patch gets truncated, but two at the beginning will remain, even if you then navigate around the filesystem relative to it.  Why is this? Is there any difference between /... and //... ?


I think that, since Earth is spherical, the amount of mass in the upper half of Earth should be the same as the second half, therefore, if the strength of gravitational field increase linearly from distance 0 to R, it should also decrease at the same rate from R to 2R, however, it will never reach zero

Would the effect of gravity on me change if I were to dig a very deep hole and stand in it? If so, how would it change? Am I more likely to be pulled downwards, or pulled towards the edges of the hole? If there would be no change, why not?


Consider the series  $$\sum_{n=2}^{\infty} \frac{1}{(\log 1)^p+(\log 2)^p+\cdots +(\log n)^p}$$  where $p>0$.  For what $p$, the series converges?  This question appears in the Tier 1 Analysis exam (2014/08) of Indiana University Bloomington. And I modify it a little to make it look more tight...

Suppose $\displaystyle a_n=\frac{1}{(\text{log}2)^p+(\text{log3})^p+...+(\text{log}n)^p}$ for $n\geq 2$ and $p>0$. For which values of $p$ does $\sum_{n=2}^\infty a_n$ converge?  So, when $p\leq 1$, $\displaystyle a_n\geq \frac{1}{(n-1)(\text{log}n)^p}$ for $n\geq 2$. Let $\displaystyle b_n=\frac{1}{(n-1)(\text{log}n)^p}$. Then $\sum b_n$ diverges since $p\leq 1$. Therefore by comparison test $\sum a_n$ diverges when $p\leq 1$.  When $p>1$, $\displaystyle a_n\leq \frac{1}{(\text{log}n)^p}$. Let $\displaystyle c_n= \frac{1}{(\text{log}n)^p}$. If $\sum c_n$ converges then I will win. But now I am stuck. Is $\sum c_n$ converges? Then how can I prove it? If not how can I conclude the state of convergence of $\sum a_n$ for $p>1$?   Can anybody please help?