Russian text breaks, but not all, when sending mail via mail function

Why after sending the Russian text: много текста ... можно настра?! ?вать свой ....много текста.... р?! ?бочих letters are lost and substituted: ?! ?   - ? The main thing comes across 2 - 3 words from the whole text. Has anyone encountered such a problem? And how can this be solved.


Prove "casting out nines" of an integer is equivalent to that integer modulo 9

Let $s(x)$ be an abstraction for casting out nines of integer $x$. For all integers $x$, prove $s(x) \equiv x$ mod $9$  I'm not asking for an answer more of a way to attack this problem. Can't think of where to start


I want to change the DPI of the screen that is used in Ubuntu 11.10. How do I do this?  I don't just want to change the font size like in , but I also want the icons to appear bigger.


First of all, thx for this site. It's great for me. I read it everyday, because I want to grow up my english skills. I'm from Poland btw. :)  My question is this:  What does it mean 'ain't'? I don't understand this language-tool. Could U explain it to me? I will be very greatfull! :)


If the triangle ABC has sides $a,b,c$ opposite to the vertices A,B,C respectively and $\Delta$ is the area.The expression $\frac{1}{\Delta}\sqrt{abc(a+b+c)}$ is   $(A)\leq16\hspace{1 cm}(B)\geq16\hspace{1 cm}(C)\leq4\hspace{1 cm}(D)\geq4$  Using Herons formula, $\Delta=\sqrt{s(s-a)(s-b)(s-c)}$ and $s=\frac{a+b+c}{2}$, given expression reduces to  $4\sqrt{\frac{abc}{(a+b-c)(b+c-a)(a+c-b)}}$ and I could not solve further to find the answer. Please help....


Why fun(k++) is wrong, but fun(++k) is ok?

Please tell me why fun(k++) is wrong while fun(++k) is okay in the following code. The error information is error: cannot bind non-const lvalue reference of type 'int&' to an rvalue of type 'int' #include <iostream>  using std::cout;  void fun(int &k) {     cout << k; }  int main() {     int k = 1;     fun(k++); // error     fun(++k); // good      return 0; }


Strange crease being formed from filling face?

I modeled two planes separately for the top and bottom of the frog's mouth, but when I try to join them together by filling a face, it creates a strange seam that creases the entire face. I've tried an edge split modifier and I don't think there could be any internal faces causing it - I've tried removing doubles but to no avail.   Since the mesh is a plane, it's entirely flat. Solidifying it does not help either.


The post editor image uploader supports drag-and-drop and it also supports pasting an image directly into the window.  The chat uploader does support drag-and-drop (as long as you drop directly into the filename text box) but does not support pasting an image into the window.  Can chat get the same  that the sites have?


How do I add multiple clocks with different time zones in Ubuntu 19.10.   Solution:   Install clock using sudo apt install gnome-clocks Open Clock app and add required timezones Restart the PC   Important: Do not install using snap or using software installer, this have permission issue to clock and multiple timezones won't appear.  Ref:


How to insert a record and then do callout?

I have a visualforce page where i get a serial number and making callout to get the related information from external system on click of a button.  Before making the callout i need to insert a record which holds the serial number so that when the callout returns the information, i can store it in same record.  But when doing this i get     CalloutException: You have uncommitted work pending   in controller method.  Am getting attachments from User to get stored in the inserted record as well. So i cannot do the insert after making callout since record id is required to use as parentid for attachment.  Visualforce page  <apex:inputText value="{!serialNumber}"/> <apex:commandButton value="Add" action="{!getSerialNoDetails}"/>   Controller  public void getSerialNoDetails() {  SerialDetailsResponse response = SerialDetailsResponse(); Serial_Details__c serialDetails = new Serial_Details__c(Serial_Number__c = serialNumber); insert serialDetails; try {     // Callout     response = SerialDetails.getSerialDetails(serialDetails.Serial_Number__c);     if(response != NULL) {         serialDetails.Material_Number__c = response.MaterialNo;         .         .                } } catch(Exception e) {     System.debug(e); }   Any idea on how to avoid this exception? Thanks in advance.


Whenever I open a .sh file, it opens it in gedit instead of the terminal. I can't find any option similar to Right Click → Open With → Other Application... → Terminal.  How do I open this file in the terminal?


Which topics are left for Stackoverflow?

With all the new ____.stackexchange.com sites coming up, I wonder if there is some reasoning on which questions do belong on stackoverflow.com.  The  says a question belongs there if it covers:   a specific programming problem a software algorithm software tools commonly used by programmers a practical, answerable problem that is unique to software development   However as far as I understand for example a "specific programming problem" would belong to    , if it is about specific code the person wrote , if it is about a design question , if it is about what library to use , if it is about user interaction.   Similar sites can be found for the other three points as well.  So my question is: Is there some kind of masterplan what stackoverflow is for? Or is it in fact meant to be the site, where everything that is not exactly covered by another site, belongs?


How can I make the curly braces on TikZ to label the x and y as in this picture?


Excel - how to either have direct data input or cell value from formula

I would like to either populate a cell value from direct key input or have the cell value derived from a formula.  Example: either directly input a number into cell A4 or have the value for A4 = A2 + A3    I don't want the formula overwritten should direct key input be used.  Thx, hope this clarifies.


Check for particular files inside a directory

I want to check directory 1 8 and 4 present inside a list of parent directory that is passed as argument to the script. PFB my script  #!/bin/bash while IFS='' read -r line || [[ -n "$line" ]]; do  cd $line echo "checking in $line" >> ../filesearch.log  if [ [ -d 1]  &&  [ -d 8]  &&  [ -d 4] ]; then echo "1 8 4 exists" >> ../filesearch.log else     echo "Dir 1 8 4 does not exist" >> ../filesearch.log fi cd ../  done < "$1"   I am getting the below error when i use if [ [ -d 1]  &&  [ -d 8]  &&  [ -d 4] ];   ./fs.sh: line 8: [: -d: binary operator expected   if we use [[ -d  1 ]]; instead of if [ [ -d 1]  &&  [ -d 8]  &&  [ -d 4] ]; my code is working fine but my requirement is to check for all the above mentioned files(1 4 8) are present in the parent directory or not.


Proof of the identity $\sum_{k=0}^{n}\binom {2k}{k}\binom {2(n-k)}{n-k}=4^n$

Prove the following identity :   $$\sum_{k=0}^{n}\binom {2k}{k}\binom {2(n-k)}{n-k}=4^n$$   I am sorry, this topic is very new to me and so is this website.  I have looked at all the "duplicates" of this question on this website, but none have had an answer that I can comprehend.  I thought I was able to just plug each one into the binomial theorem and arrive at the answer, but my professor stated that I am using the theorem incorrectly.  I do not have an intuitive understanding of proofs yet.  Any direction will help!  Thank you.


What's the best way to completely remove everything from a computer, without re-installing?

I have a friend who wants to sell their computer, but obviously all personal information and software that it is on it needs to be removed before doing so.  Usually I would format and reinstall it, but I cannot easily get hold of the required XP DVDs and I'm not 100% sure the serial number is stuck on the case as usual so getting hold of it will probably require more effort than I'm prepared to spend.  So, what's the best and quickest way to remove and uninstall everything from the PC without reinstalling it?   Thanks.  EDITS: I'm looking to remove things like Internet History and all installed programs, too. I know how to remove the history and each individual program, but that could take hours.  The machine is not branded and therefore there is no website I can go to download recovery software. There is no recovery partition on the computer and I'm not aware of any recovery DVDs for it either. I can only assume it was installed from a retail copy, and therefore there is no way to recover it to factory settings.  It needs to have XP installed, not any distribution of Linux. Like most average people, the person getting the computer will not understand what to do with a computer that doesn't have Windows installed, and software like Office does not work on Linux either.  Buying another licence is not really an option either. She has just brought a laptop to replace the computer, so buying another licence for a computer that she's getting rid of doesn't really make sense.  Thanks for all the help so far!


Infinite product proof without using gamma function

How do you show that the infinite product of $(3n+1)/(3n+2)$ converges to zero without using the gamma function (as I can tell the gamma function solution has already been presented here)?  I've tried using a number of different strategies, but I still don't seem to be able to land on a good approximation.


How can I benchmark individual cores? I want to see if they are all operating at the same speed. I'm a bit confused if my Cortex A53 device has  or not, I'm reading conflicting information on the internet, so I want to test it myself.


Export model with Enviroment Texture and Texture coordinate

I have built a simple model where I project an equirectangular image to a mesh using an environment texture. Sometimes the image is not centered correctly so I do this by linking the image location to another mesh using a texture coordinate node (which fixes the distortion). The setup in the material tab is shown here  My challenge comes in exporting this in a format that I could use in a web browser. I have tried to export to glTF but the material is not exported with the model. I tried an alternative method using an image texture instead and this material does get exported but the texture coordinates are still lost and so the material maps incorrectly. Has anyone had success in exporting this setup before?


How to recalibrate the OS for an external battery?

I recently bought an external non-standard 7000 mAh battery for my Samsung Galaxy S3 but the phone doesn't seem to recognize it.  Is it possible that the phone needs to be reconfigured or recalibrated so as to recognize the difference in the battery capacity?


Prove that there is a non-zero distance between any point outside an open set and any point in a closed-bounded subset (Complex Analysis)

Question: If $S \subseteq \mathbb{C}$ is open and $L \subset S$ is closed and bounded, show that there exists a $\delta$ such that $|z-w|>\delta$ for all $z \in L$ and $w \notin S$ Attempt: I am considering the set $P := K^C \cap S$ which is open as $K^C$ is, so for every element $a$ of $P$, we can find an $r>0$ such that this is the radius of an open ball centered at $a$ contained in $P$.  I now want to set $\delta$ to be the minimum of all such $r$ such that $r$ is the maximum for a particular point $a$. However, I am not sure how to show that this set even has a minimum element, and I feel that this probably isn't even the case. I can imagine a set in which $P$ kind of bottlenecks and the set of all $r$ wouldn't have a minimum, but an infimum of $0$.


Possibility of attaching non-spatial files to features in QGIS

I try to open a hyperlink from a feature in QGIS using the Windows options. I managed to make a hyperlink working, by copying in the edit action tab, the Adobe Acrobat path, the field name and the destination field, but it shows error messages. If I close the messages, I can visualise the document.


Are members of a diagonal positive definite matrix positive?

If square matrix $M$ is diagonal and positive definite, does it mean that all $m_{ii}$ (diagonal entries) of this matrix are necessarily positive?


I’d like to have Bluetooth disabled automatically when I login to my user account. Is there any way to achieve this? I’m running macOS Sierra, and have blueutil installed.


Let $T$ and $T^{'}$ be topologies on set $X$ such that $T \leq T^{'}$. If $(X,T^{'})$ is path-connected, is $(X,T)$ path connected?

Let $T$ and $T^{'}$ be topologies on set $X$ such that $T \leq T^{'}$. If $(X,T^{'})$ is path-connected, is $(X,T)$ path-connected?  I think it is, and I tried to prove it by contradiction, but I got stuck. Any hint helps!


What is the usual dress code for academic workshops?

I'm attending my first academic/industry workshop next week and was wondering what is the convention with regards to the dress code. It's a three-day affair where each participant is required to present a 3 minute introduction to their PhD. Other than that the event consists mostly of talks by other people.  Normally, I'd go with formal business wear if I were presenting as a named part of the programme. If I was just attending I'd go for 'academia-casual'. That being said, I've never been to a workshop so I probably don't know what I'm talking about, especially with the inclusion of the 3 minute 'introduce yourself' presentation.  The workshop takes place in the United Kingdom and the field is engineering/computer science.


Prove that ${x dy - y d x\over x^2 + y^2}$ is not exact

Please can someone verify my proof that $$\psi = {x dy - y d x\over x^2 + y^2}$$ is not exact? Here is my work: If $\psi$ was exact there would exist $f:\mathbb R^2 \setminus \{0\} \to \mathbb R$ such that $df = f_x dx + f_y dy = \psi$. Here $f_x = {-y \over x^2 + y^2}$ and $f_y = {x \over x^2 + y^2}$. It would hold true that $$\int f_x dx = \int f_y dy = f.$$ So I calculate these integrals: $$ \int f_x dx = -{1\over 2}\log(x^2 + y^2)$$ and $$ \int f_y dy = {1\over 2}\log(x^2 + y^2)$$ It is clear that these cannot be equal therefore $\psi$ is not exact. Edit The first thing I had tried (it did not work) was to calculate the integral along a closed curve: $$ \int_{S^1}\psi = \int_{S^1} {x \over x^2 + y^2} dy - \int_{S^1} {y \over x^2 + y^2} dx = \int_{S^1} x dy - \int_{S^1} y dx= x \int_{S^1}  dy - y \int_{S^1}  dx = 0$$ since $\int_{S^1}dx = 0$.


How to execute same command "X" multiple times with a time delay of some number of seconds?

I know how to execute multiple commands at same time but now what I need is to run the same command multiple times with some time delay between the command execution.  Requirements   I don't want to use a script for this A single one line command to accomplish this Needs to run on Linux Need to control the number of times the command will run


Prove that : $$\sum_{k=0}^{\infty} \frac{(-1)^{k}}{(2k+1)^3}=\frac{\pi^3}{32}.$$    I think this is known (see ), I appreciate any hint or link for the solution (or the full solution).


beginner python name formatting and slicing strings

I am taking a course in basics to python and I am stuck on this lab where we have to take the input a full name: ex Pat Silly Doe and print it as Doe, P.S. or in the case they did not input a middle name it would just read: Doe, P. We are only on slicing and formatting strings no if else yet but I feel I am overthinking this I know I need to slice the input and I can do that by: name = input() splitname = name.split(' ') print(splitname)  and that will split each part of the user inputs name up by the whitespaces entered which will then let me know if its 2 names or all 3. But I am kind of lost now as to what to do next. Now that I have the name split up how do I without printing it take each name and format it. I'm not trying to get a direct answer to the lab I don't want to just copy paste code in to do it, I just want a little bump in the right direction.


Book about suppressing First Contact? Character "Polly Ling"?

This paperback was probably from ca. 1970. The well-off don't want their apple-cart upset by alien tech. Hero saves "Polly Ling" from an alien monster, which turns out to be her husband- she's an alien.


How can I figure out who has visited my profile?

How can I find out who are my profile visitors?


Oracle: how to UPSERT (update or insert into a table?)

The UPSERT operation either updates or inserts a row in a table, depending if the table already has a row that matches the data:  if table t has a row exists that has key X:     update t set mystuff... where mykey=X else     insert into t mystuff...   Since Oracle doesn't have a specific UPSERT statement, what's the best way to do this?


I can use time to get running time statistics:  % time zsh --version zsh 5.6.2 (x86_64-pc-linux-gnu) zsh --version  0.00s user 0.00s system 86% cpu 0.005 total   How can I time how long a source script takes to run?   % time source $NVM_DIR/nvm.sh %


Conditionally format a cell if it contains formula

Is it possible to conditionally format a cell if the cell contains formula (to alert myself and other users when updating the cell)?


What are the possible subspaces of $V$ when $dim(V)=1$?

If we say $V$ is $dim = 1$, can we say the only possible subspace is $sp\{0\}$?


Is plane wave equation $\Psi(\mathbf r,t)=\Psi_0e^{i(\mathbf k \cdot \mathbf r-\omega t)}$ for quantum-mechanical wavefunctions really complex?

The equation given for plane sine wave (for instance used to "derive" the Schrödinger equation) is  $$ \Psi(\mathbf r,t)=\Psi_0e^{i(\mathbf k \cdot \mathbf r-\omega t)} $$  I would have assumed that it would be equal to the REAL part of this complex number, i.e. a cosine (or a phased sine). But all the explanations I looked at on the net seem to say that the complex representation is equivalent. As a matter of fact the derivation of Schrödinger's equation starts with the assumption that the wave equation is equal to the above, which yields to complex results in Schrödinger's equation.  I am totally confused. It's just as if we said that the Real part (or the Imaginary part) of this complex expression was equivalent to the full complex expression...  Please note that I am NOT asking why we use complex numbers in quantum mechanics, but why we say that a wave function can be expressed as a complex value, combining cos and sin in the complex plane, while it actually only is equal to a sin (or cos) function.  EDIT: @probably_someone I think your answer/question points me in the right direction. Let me know if I am correct.  My confusion is that I have seen in a lot of instances on the web people saying that a plane progressive sine wave amplitude could be expressed as in the complex equation above. This is wrong (hence my troubles). The equation of a plane sine wave is purely real (i.e. with values in $\Bbb R$): $w(x,r)=A.cos(\omega t-kx-\phi )$.  However when we use this as the Real part of a complex number (using Euler formulas), it becomes easier to derive results such as, for instance, the probability of finding a 'particle' (using old QM terminology) in some place at some given time, by using the squared module of that complex number. Please confirm. Thanks.


I'm looking for a way to monitor the power being drawn from the USB ports on my Mac.  System Profiler doesn't appear to display this and I haven't been able to find any applications or tools to do the job either.  Can anyone suggest anything (preferably software based)?


How can I change all the Windows 10 privacy settings without dozens of clicks?

Windows 10 introduced many new features which leak personal data to Microsoft, you can turn most of them off but it involves a lot of clicking and research because they are not all in one place.   A good list of these settings is at   I would like some sort of batch file that can change all these settings in one go.


Jump/Scroll to selected object in the outliner?

How can I jump to the selected object in the out-liner, I've got over 200 objects in my scene, all named cube.___ ... and I can't seem to find my selected object. How can I jump to it?


how to open version 2.79 files in version 2.90

I need to pull my 2.79 projects into version 2.9(and up). When I try to open (a copy) only a few objects show up. The collections window shows all parts and they are enabled for viewing (eyeball icon), if I click on one of them its name appears in the viewport but the object is nowhere to be seen nor is the object origin dot. How can I get these files into 2.90 ready to work with?


How do I find which disk/partition current directory is on?

I can print current directory using pwd, but this gives me the path I navigated to get to where I am. I need to know which disk/partition current directory is on.   For example, if I create symlink user@pc:~$ ln -s /media/HD1 hard_disk and then navigate to ~/hard_disk and run pwd it will print /home/user/hard_disk.  I would like to get the actual path I'm currently on or better just the actual filesystem I'm currently on, which corresponds to one in df.


Cursor keeps busy for 15 seconds when runnig a command from a launcher icon

Following  easy guide I was able to create a .desktop file. my goal was to pin this desktop file to the launcher and add two commands to it as quick list items here is what I did :  [Desktop Entry] Name=Launcher2Dock Comment=Turnes you laucher intoto dock Exec=gsettings set com.canonical.Unity.Launcher launcher-position Left Icon=/home/mushir/Desktop/icon.svg Terminal=false Type=Application Categories=Utility;Application; Actions=Move bottom;Move left [Desktop Action Move bottom] Name=Move bottom Exec=gsettings set com.canonical.Unity.Launcher launcher-position Bottom OnlyShowIn=Unity;  [Desktop Action Move left] Name=Move left Exec=gsettings set com.canonical.Unity.Launcher launcher-position Left OnlyShowIn=Unity;    everything worked just fine but I found that the mouse cursor turns into the wheel shape for about 15 seconds after runing the command from the .desktop file quick list pinned to the laucnher


How busy is the Roman Colosseum throughout the year?

I just spent a week in Italy, and found that the tourist crowds are more annoying than I had anticipated. I found I was simply unable to enjoy myself due to the crowds, so I ended up skipping some of the common highlights, such as entering the Roman Colosseum, and many of the exhibits at the Vatican Museum.  If I want to return to Rome at a later date, when can I enjoy these sites, and specifically the Roman Colosseum, with the smallest crowds?  What is low season? And if there is a difference, which is the lowest volume day of the week during this season? Weather, travel prices, hotel availability, etc, don't matter. I just want to enjoy the sites with few other people.  Also, if it matters, I'm only interested in entering the sites as a normal member of the public (special group reservations, exclusive invitations by the Pope, etc, are not of interest to me).


Is there a multi-threaded cp command on Linux?  I know how to do this on Windows, but I don't know how this is approached in a Linux environment.


Q: Show that $\mathbb {RP}^n$ is not orientable for $n$ even.  First I looked at the definition for orientability for manifolds of higher degree than 2, because for surfaces I know the definition with the Möbius strip.     A n-dimensional manifold is non-orientable if it contains a homeomorphic image of the space formed by taking the direct product of a (n-1)-dimensional ball B and the unit interval [0,1] and gluing the ball B×{0} at one end to the ball B×{1} at other end with a single reflection.   The projective space can be seen as $\mathbb S^n/\mathbb Z_2$ or $\mathbb D^n$ with antipodal points identified on the boundary.  I have looked at other similar questions like   In that thread someone states that the antipodal map is orientation preserving if $n$ is odd and reversing when $n$ is even. Why is this? Intuitively the antipodal map can be constructed by combining $n+1$ reflections in the hyperspaces $x_i=0$ and if $n$ is odd $n+1$ is even and combining an even amount of reflections is orientation preserving and the other way around for $n$ even and $n+1$ odd. I need a hint for a rigorous proof.  Also after I establish this for myself, I need to show that in  $\mathbb D^n$  with n even and with antipodal points identified on the boundary the higher dimensional analogue of Möbius strip, which has just one reflection, can be embedded.   The subset to which it would be homeomorphic is obvious, but I would like a hint in showing that the the different reflections yield the same space.


Converting the javascript object to json object

I am creating a object of logMessage.  logMessage = function (msg, severity, vendorId, userName, actionPerformed, priority, traceId, dataSent) {     this.message = msg;     this.severity = severity;     this.vendorId = vendorId;     this.userName = userName;     this.actionPerformed = actionPerformed;     this.priority = priority;     this.traceId = traceId;     this.dataSent = dataSent; };  var msg = new logMessage(err, "High", "none", qry.username, "Error on login call: /req/login", "high", "", qry); Utility.writeToLoggly(msg);   err ,qry are json objects; How do I convert the the msg object to json object ? I am sending the msg object to loggly for the log management. It would be great if I could send the correctly formated json object to loggly .


Calculating the drag force provided by a laminar flow

If I drop a ball into  viscous fluid (e.g. oil), by calculation I know that the fluid flow is laminar. So which equation do I need to calculate the drag force provided by fluid?    The drag equation, $$ F=\frac12\rho CAv^2 $$ where $ρ$ is the density of fluid, $C$ is drag coefficient, $A$ is cross-sectional area of ball, and $v$ is the velocity of ball. Or the Stoke's law, which is  $$ F=6\pi\eta rv$$  where $\eta$ is the viscosity of fluid, $r$ is radius of ball, and $v$ is velocity of ball.


C++ : Finding instances of a class in a vector of superclass

I'm trying to have an boost::container::vector containing instances of a few class that all inherit from the same superclass, and then have some functions only apply to the instances of a specific class, but I can't seem to get it to work.  This is the first time I try this, so maybe I just made a rookie mistake, can one of you tell me where I went wrong, and why ?  Here's an example code :  using boost::container::vector;  class card{ public:     card(int aa,int bb):a(aa),b(bb){}     virtual ~card(){}     int a,b; }; bool operator==(card l, card r){ return l.a==r.a; } bool operator<(card l, card r){     if(l.a<r.a){ return true;}     else{ return l.b<r.b; } } std::ostream& operator<<(std::ostream& os, card c){     os << c.a << ":" << c.b;     return os; }  class subcard:public card{ public:     subcard(int a, int b):card(a,b){}     virtual ~subcard(){}     int c=0; };    int main() {     cout << "Hello, World!" << endl;     vector<card> v1;     v1.push_back(card(2,2));     v1.push_back(subcard(1,1));     for (int i = 0; i < v1.size(); ++i) {         cout<<v1[i]<<endl;     }     for (int i = 0; i < v1.size(); ++i) {         if(subcard* sc = dynamic_cast<subcard*>(&(v1[i]))){             cout<< "found : " << sc <<endl;         }     }     return 0; }   Thank you very much :)


When does Brotherhood and the 2003 series split?

So I've watched FMA: Brotherhood and Star of Milos. I want to watch conqueror of Shamballa but it seems like it continues from the  original series.  I don't want to have watch the original series since I know that the earlier portions of the story are the same as Brotherhood . Is there an episode in the original series I can start watching from that's starts to have a different story path from Brotherhood? Or should I just read about the originals ending?


Proving that the average approaches zero

If the positive numbers $v_n$ approach zero as $n\to\infty$, prove   that their average $(v_1+v_2+\dots+v_n)/n$ also approaches zero.   We have:  For any $\epsilon$, there is an $N$ such that $v_n<\epsilon$ if $n>N$.  We need to prove:  For any $\epsilon$, there is an $N$ such that $\frac{v_1+v_2+\dots+v_n}n<\epsilon$ if $n>N$.  I am having a hard time connecting these two statements. I have tried with examples but I have not been able to get through these symbols. Intuitively, average follows instantaneous. $\bar v$ rises and falls with the next $v$. But I need a formal proof.


How can I prevent the display on an iOS device from dimming and turning off?

I'm diving into iOS development and am building my own alarm clock app to become familiar with platform and SDK. I've noticed some alarm clock apps in the app store keep the screen from dimming and/or turning off when their app is running. How is this implemented?


Where did the "play on realms" option go?

My Minecraft app now only has the option of "play" and there is no "play on realms" to be found!  I downloaded - and paid for - the multiplayer app, but there doesn't seem to be a way to get to any realms on that app either.


Changing align environment tag styles and colors

I'm using amsmath and amsfonts to typeset my homework, and since it will be read on a screen, I would like to make \tag{comments inside equations} differently colored, and optimally downsize them by a few points.   While I could put \color and font instructions in every \tag instance, I've got them scattered all over the place and would like a unified way to change it globally. I have figured out how to use the sectsty package to color all section fonts to make them stand out on-screen slightly, is there a similar method for amsmath's align environment and tags?  Forgive my extreme TeX ignorance. Also forgive my math ignorance... here's some sample stuff:  \begin{align*} A &= B \\ &= \frac{B}{\text{sometimes the equation gets really long so the tag goes on the next line}} \tag{Here is where I say something stupid} \\ &= \frac{1}{0} = \infty \tag{Tags often include math, like $\frac{\sin \theta}{\theta}$} \end{align*}


Suggested review count at top is incorrect

The suggested edits count at top is incorrect. Multiple browser refreshes did not clear it. Approving/Rejecting review decreases the count, but as you can see the count is incorrect.


From my limited knowledge: The Unix OS coder assumes the user knows what they're doing, etc. versus the Apple's you can only do it the way you are allowed to do it, etc.  Compared to other variations of Unix, what are Mac OS X's limitations, but also does it improve the user experience?  To try and clarify the question, it's more the user experience I'd like to read find out about. Although it's of interest that it's certified, that's not so relevant - Linux is not certified, but it's the closest I've come to using Unix up till now.


Sums of complex numbers - proof in Rudin's book

I have one question about a proof in Rudin's book:  If $z_1 ..., z_N$ are complex numbers then there is a subset $S$ of  $ \{1,..., N \}$ for which $|\sum_{k \in S} z_k| \ge \frac{1}{\pi} \sum_{1}^N |z_k|$  Proof:  Write $z_k = |z_k| e^{i \alpha_k}$.   For $\phi \in [- \pi, \pi] $ let  $\ \ S(\phi):= \{ k | \cos (\alpha_k - \phi)>0 \}$.   Then $|\sum _{S(\phi)} z_k| = |\sum_{S(\phi) } e^{-i \phi} z_k| \ge Re(\sum_{S(\phi) } e^{-i \phi} z_k) = \sum_1^N |z_k| \cos ^+ (\alpha_k - \phi) $.  Could you tell me why the two equations hold (the inequality is quite obvious) and what $\cos ^+$ stands for?


BASH. Make the result of one command to be an argument of another

How can I make the result of one command to be an argument of another?  I'm trying to kill child process by pid of parent process and use for it pgrep  Example: pgrep -P <PID>  But after I need to kill the PID which I get from pgrep  pgrep -P <PID> | kill  - it doesn't work(  Thank you!


What term is used for the closing of a letter?

Salutation is the term used to describe the beginning of a letter or other correspondence. What is the term used for the closing of a letter? Here are some examples: Yours truly, Sincerely, Best wishes, Love?  Searching for 'antonym of salutation' was not helpful.  EDIT: This need not be expressed as a single word. (Whatever is correct is fine, whether one word or a phrase!)  1. Citation (IEEE Style):  in Roget's 21st Century Thesaurus, Third Edition.  Source location: Philip Lief Group 2009.


Showing $\mathbf Q(\sqrt2,\sqrt3)=\mathbf Q(\sqrt2+\sqrt3)$   BUT I want to show this using The Theorem of the Primitive Element,       So I have to verify that $c$ cannot be $1$ and I need the $\mathbf Q$-monomorphisms, what are these ?


Some start menu shortcuts are missing on Windows 10

Not sure when this started happening but some time after upgrading to Windows 10 I noticed some of my search results were not showing up with what I wanted. For instance, when I searched for Word 2013 or Skype, I did not get any results. I decided to investigate and tried rebuilding the indexing file and moving it to a new location but it made no difference.  So I checked my start menu and manually tried looking for the shortcuts only to discover that they strangely weren't there. Also notice how some of my tiles have suddenly disappeared.    Strangely enough when I browse the actual location of the start menu folder, the shortcut for Word and Powerpoint are there.    I've checked that none of the folders/shortcuts are hidden or read-only and that the files/folders have sufficient permissions via the Security tab.  Any ideas how to solve this?


I searched around a bit for this question, but I could only find people wondering what happened to their reputation on Meta, rather than why.  Recently I've been posting a few helpful questions on ELU Meta and I have received a number of upvotes. I was confused as to where the reputation from them was going until I read that Meta votes don't "count". Why is this the case? Isn't contributing to a site designed to discuss and improve another site a helpful activity that should be rewarded?


I have reset my world spawn to a distant place. how can I get back to the original world spawn area?

I teleported far away from my house using /locate. I went to a stronghold and set my spawn there thinking I might die several times. After defeating the dragon, I realized that I couldn't find my house. I was in the middle of nowhere, and even my map (made to the largest possible size) didn't show anything. Now I can't find my old house, which took me over 11 hours to make. Compasses won't work since I reset my world spawn. Is there any possible way to find my house, or is there no chance? I am in creative mode.


Oracle SQL - Select First n Distinct Rows

In Oracle 12, we finally have a limit feature, so we can simply  select distinct columnname from mytable fetch first n rows only;   However, I am presently stuck with a previous version and would like to know how to achieve this result.  Ideally the query should return rows immediately, even for a huge table.  It should return results as soon as the N distinct have been found, instead of processing all rows.


How to extract the following C code into a function?

I am trying to move some c code into the the separate function. The program counts the length of the line in the file.   #include <stdio.h>  int main() {     const int max = 255;     int counter = 0;     FILE *f1 = fopen("maps/map1.txt", "r");     char buff[max];      while (fgets(buff, sizeof (buff), f1))     {         counter++;     }     printf("%d\n", sizeof (buff));  // 255     printf("%d\n", counter);        // 23     fclose(f1);     return 0; }   Counter indicates 23, which is the correct result and the size of the buff variable is 255, as declared.  These simple implementations were moved to a separate function getLineWidth(). Unfortunately, I can't get the correct results.   #include <stdio.h>  int getLineWidth(char * buffer, FILE * file);  int main() {     const int max = 255;     int counter = 0;     FILE *f1 = fopen("maps/map1.txt", "r");     char buff[max];     printf("%d\n", getLineWidth(buff, f1));          // 299     fclose(f1);     return 0; }  int getLineWidth(char * buffer, FILE * file){     int counter = 0;     printf("%d\n", sizeof (buffer));                // 4     while (fgets(buffer, sizeof (buffer), file))     {         counter++;     }     return counter; }   The size of the buffer variable is 4, which probably indicates the size of the char, not the size of the array buff passed to the function.The function also returns an incorrect result - 299.   Please help me with this part of the code and show me where I made the mistake.


Are there cheap GPS or other navigator devices with downloadable maps for the whole world?

I don't need a recommendation or a list but my knowledge of GPS and "navi"s and the differences between them is an utter mystery to me.  But often I'm lost in backstreets in random countries where access to something like a live Google Maps would be awesome. I absolutely cannot afford a smartphone with worldwide roaming though.  Can GPS's do what I want or am I barking up the wrong tree? If they can is it only high end ones than can?


currently we have a $(G,*)$ group, which order is $2k$. Prove existence of non $e$ item $a$ in the group,  such that $a^2 = e$. I am currently out of ideas, can you give me any hint. Thanks.


Is there a way to know when a systemd timer will run next?

I am testing a systemd timer and trying to override its default timeout, but without success. I'm wondering whether there is a way to ask systemd to tell us when the service is going to be run next.  Normal file (/lib/systemd/system/snapbackend.timer):  # Documentation available at: # https://www.freedesktop.org/software/systemd/man/systemd.timer.html  [Unit] Description=Run the snapbackend service once every 5 minutes.  [Timer] # You must have an OnBootSec (or OnStartupSec) otherwise it does not auto-start OnBootSec=5min OnUnitActiveSec=5min # The default accuracy is 1 minute. I'm not too sure that either way # will affect us. I am thinking that since our computers will be # permanently running, it probably won't be that inaccurate anyway. # See also: # http://stackoverflow.com/questions/39176514/is-it-correct-that-systemd-timer-accuracysec-parameter-make-the-ticks-slip #AccuracySec=1  [Install] WantedBy=timers.target  # vim: syntax=dosini   The override file (/etc/systemd/system/snapbackend.timer.d/override.conf):  # This file was auto-generated by snapmanager.cgi # Feel free to do additional modifications here as # snapmanager.cgi will be aware of them as expected. [Timer] OnUnitActiveSec=30min   I ran the following commands and the timer still ticks once every 5 minutes. Could there be a bug in systemd?  sudo systemctl stop snapbackend.timer sudo systemctl daemon-reload sudo systemctl start snapbackend.timer   So I was also wondering, how can I know when the timer will tick next? Because that would immediately tell me whether it's in 5 min. or 30 min. but from the systemctl status snapbackend.timer says nothing about that. Just wondering whether there is a command that would tell me the delay currently used.  For those interested, there is the service file too (/lib/systemd/system/snapbackend.service), although I would imagine that this should have no effect on the timer ticks...  # Documentation available at: # https://www.freedesktop.org/software/systemd/man/systemd.service.html  [Unit] Description=Snap! Websites snapbackend CRON daemon After=snapbase.service snapcommunicator.service snapfirewall.service snaplock.service snapdbproxy.service  [Service] # See also the snapbackend.timer file Type=simple WorkingDirectory=~ ProtectHome=true NoNewPrivileges=true ExecStart=/usr/bin/snapbackend ExecStop=/usr/bin/snapstop --timeout 300 $MAINPID User=snapwebsites Group=snapwebsites # No auto-restart, we use the timer to start once in a while # We also want to make systemd think that exit(1) is fine SuccessExitStatus=1 Nice=5 LimitNPROC=1000 # For developers and administrators to get console output #StandardOutput=tty #StandardError=tty #TTYPath=/dev/console # Enter a size to get a core dump in case of a crash #LimitCORE=10G  [Install] WantedBy=multi-user.target  # vim: syntax=dosini


Don't list all users at login with LightDM

I just upgraded to Ubuntu 11.10 and I was wondering if it's possible to not list all the current users and instead require the user to type in their username? My company's IT policies require that users not be listed on login screens.  In Ubuntu 11.04, I was able to do this with the following commands...  $ sudo -u gdm gconftool-2 --type boolean --set /apps/gdm/simple-greeter/disable_user_list true


Is there any way to replace "words" in Adobe Illustrator?

I made a book in Illustrator, and I would like to replace a word with another word (e.g "Bread" into "Rice"). If I was using MS Word, I could simply Ctrl+H and do a word replace. How about in Adobe Illustrator?


Is there a way to "neutralize" the sweet vanilla smell of almond milk?

I always buy Alpro's vegetable milks that don't have a sweet smell (I think it's vanilla). This week I couldn't find it. I want to make a white sauce for potatoes. Is there anything I can do to improve this smell?


Can I use the phrase "Can I get x please" and have it considered 'proper' english?

I seem to say it quite a lot without really realising it. I know of course, it should probably be something along the lines of "May I have" - But is "Can I get" really that wrong?  Thanks


How to flatten a face to avoid distortion (make an ngon planar)

I created a kind of procedural modeled ground (rocks desert like), with some decimate modifiers to have a really crazy topology.  The result is nice, except for some ngons faces that contains some weird normals, due to the elevation difference of several vertices:    How to avoid this? My first guess is to "flatten the face, but I can't figure out the way to do this operation.  I must specify that the face is not perpendicular to the Z axis, so a zero-Z-scaling (S Z 0) won't work here.


How do I downgrade a jailbroken iPhone 4 on iOS 7.0.3 to iOS 6.X.X?

I know about other similair questions on AD, but they are from quite a while ago. Things can change quickly.  I do know about this method:   But iFaith can't find any SHSH blobs for my phone.  I have not saved any SHSH Blob's because got the phone and jailbroken it two days ago.  So here's the september 2014 question:  I'm on a jailbroken iPhone 4 iOS 7.0.2, can I downgrade to iOS 6.X.X? If yes how?


Change the background of an active icon on a menu in JavaScript

I'm trying to make a blue background color to stay on the SVG icon that is active displaying the text using pure JavaScript. I'm also getting icons from semantic UI. This is the code of the current menu list, and so far clg prints me the items inside for: HTML     <svg><svg/>     <svg><svg/>     <svg><svg/>     <svg><svg/>          CSS .menu-bar {    display: block;    width: 100%;    height: 100%;    margin-top: -10px; }  .menu-bar svg {     display: inline-block;     width: 1em;     padding: 0.3em;     border-radius: 4px;     margin-right: 20px; }  .menu-bar a.toggle-state  {    background-color: #1A41B5; }  JavaScript code (so far) function changeIndex(){     for (let i = 0; i <= items.length; i++) {         console.log(items[i])     } }   I managed to fixed it with: function _clearIcon() {     for (const icon of items) {         if(icon.classList.contains('menu-barActive')) {             icon.classList.remove('menu-barActive')         }     } }  function changeIndex() {     for (const icon of items) {         icon.onclick=()=> {             _clearIcon()             let activeId = document.getElementById(icon.id)             activeId.classList.add('menu-barActive')         }     }


I'm trying to gain intuition for matrix norms. I'd like to know why if $A\in\mathbb{R}^{n\times n}$ that $||A||$ is equal to both $\max _{x\in\mathbb{R}^n}\frac{||Ax||}{||x||}$ and $\max_{||x||=1}||Ax||$. Why are these two definitions equivalent?


Orders of $GL_2$ and $SL_2$ over the field $\Bbb Z_p$

So as I see it, if I find $|GL_2|$ I can simply divide it by $|\Bbb Z_p^*|=p-1$ to find $|SL_2|$, because $GL_2/SL_2\cong\Bbb Z_p^*$, so the problem comes down to finding $|GL_2|$. To find it, I was thinking in the following direction: the matrix can have at most $2$ zeros (otherwise it wouldn't be invertible), so if we denote by $N_i$ the number of nonsingular matrices with $i$ zeros in them, $|GL_2|=N_2+N_1+N_0$. If the matrix has $2$ zeros, then they are either on the main diagonal or the opposite one and in either of those cases the number of invertible matrices is $(p-1)^2$, so $N_2=2(p-1)^2$. By similar reasoning, $N_1=4(p-1)^3$. What I'm much less sure about is the value of $N_0$, i.e. the number of nonsingular matrices with nonzero entries. Would the following be correct?     There are $(p-1)^2$ possible choices for the first column (or row, however you view the determinant), and since the second column cannot be a multiple of the first, $(p-1)^2-p$ possible choices for the second one. Therefore, $N_0=(p-1)^2((p-1)^2-p)$   After some simplification, that would make $|GL_2|=(p-1)^2(p^2+p-1)$ and $|SL_2|=(p-1)(p^2+p-1)$.  Edit: The correct solution to this according to my book is $|GL_2|=p(p+1)(p-1)^2$, with $|SL_2|$ following from that, so what did I do wrong? As I see it, that's essentially my answer, without the constant term in the quadratic. Where exactly was I wrong?


I am an Indian. I wanted to stay in Spain for one month, but by mistake my bookings were for 20 days only, so accordingly the Spainish Embassy has allowed me only 20 days.    How can I extend my visa, or can I apply online in any other nearby European countries?


How to texture a downloaded model made of stretched triangles?

I'm a beginner in blender. Trying to texture a 3d furniture model which was downloaded from the manufacturer site. Geometry is made of stretched triangles. This causes problems of stretched texture which is visible on render.  I unwrapped the model with "smart uv project" but the geometry is still stretched Is there any solution to texture it properly or I need to remodel it to make it quads?  What if I need to use dozens of real furniture models like this?  Should I model everything from scratch in blender?  some pictures to explain:enter image description here


How can I determine if a used game is pirated?

How can I tell if used GBA/DS games are pirated?


For my mom's birthday we had a photoshoot with the grandchildren. The photo we would like to print on a canvas is 3530 x 2353 and the desired size is 140 cm x 93.3 cm. Now the software says that the DPI is too low. Can somebody please help?  Is there a way to change the DPI or is the quality of the photo just too low for the size? That would be a pity, because we payed a lot for these professional photographs.  Greetings,  Silke


I have debian on my VPS server and suddenly it stops to work. It says that  root@vps-16746:/# cd ~ root@vps-16746:~# mkdir 3 mkdir: cannot create directory `3': No space left on device   If I press TAB I'll get -bash: cannot create temp file for here-document: No space left on device. But it seems that I have enough space  root@vps-16746:~# df -h Filesystem                                              Size  Used Avail Use% Mounted on rootfs                                                   29G  5.0G   22G  19% / udev                                                     10M     0   10M   0% /dev tmpfs                                                    99M  244K   98M   1% /run /dev/disk/by-uuid/4546171a-7358-4c50-b66d-c86162f4d52d   29G  5.0G   22G  19% / tmpfs                                                   5.0M     0  5.0M   0% /run/lock tmpfs                                                   299M     0  299M   0% /run/shm /dev/xvda1                                              194M   24M  160M  13% /boot   Any advice?


Integer solutions of the equation $x^2+y^2+z^2 = 2xyz$

Calculate all integer solutions $(x,y,z)\in\mathbb{Z}^3$ of the equation $x^2+y^2+z^2 = 2xyz$.   My Attempt:  We will calculate for $x,y,z>0$. Then, using the AM-GM Inequality, we have  $$ \begin{cases} x^2+y^2\geq 2xy\\ y^2+z^2\geq 2yz\\ z^2+x^2\geq 2zx\\ \end{cases} $$  So $x^2+y^2+z^2\geq xy+yz+zx$. How can I solve for $(x,y,z)$ after this?


When a character levels up and gains new spell slots, are those slots available immediately or do they have to rest before they can use those slots?


Let  $(X_{i} \colon i \in I ) $ be a family of discrete topological spaces so that $card(X_{i}) \geq 2\  \forall i \in I$ . Prove that the product $ X = \Pi_{i \in I} X_{i}  $ is discrete $\iff$ $I$ is finite .   I know that you will think this is a duplicate but I am looking for the proof for : if the product $ X = \Pi_{i \in I} X_{i}  $ is discrete then $I$ is finite. The other direction is easy.


kdenlive won't see my external hard drive. I have heard that it's a common issue. ..is there a new fix yet ?


How to open a webpage in Chrome from PowerShell script?

I am creating a large PowerShell script to change a bunch of system preferences and personalization options, as I am using a computer cluster where everything is wiped upon restart and I simply cannot be productive with the default settings.  More specifically, I would like to also enable "Ask where to save Downloads" in Chrome and change the default search engine from Google to Bing. I know of no way to do this from a script, and I don't think it's as simple as copying a file over that will change those settings, so I thought I could at least have my script open the settings window so I can do that more easily.  I can't figure out how to get PowerShell to open Chrome to a specific webpage. For example, the following does not work:  Start-Process -FilePath "C:\Program Files (x86)\Google\Chrome\Application\chrome.exe" -ArgumentList 'chrome://settings/?search=ask+where'   I can open Chrome itself from PowerShell but not to anything but this page. I have tried moving the quotes around behind and after the Argument List, enclosing everything in quotes, and every other possible combination of quotes, etc.  I have spent an hour looking for solutions online. Every one of them entails either:   PowerShell opening the webpage, but using the default browser. (Chrome is not the default browser, and I am opening Chrome specific links anyways so that would not work in the default browser). Opening Chrome with arguments that change how Chrome opens - i.e. "--incognito" for opening in Incognito.   I have found nothing that will let me open a webpage in Chrome. Is this even possible?  I realize now that the problem is the URL I am attempting to open, rather than the code which is fine.  However, I cannot do anything in the suggested answer. I can't make any changes at all to the filesystem, because everything is wiped upon logout. Hence the ps1 script to setup the environment. It needs to be quick so I can't copy over an entire GoogleChromePortable directory.


Which test to use in a single group pre- and post-treatment analysis

I am attempting to analyse pre-existing data (using SPSS). I have one group of participants, 4 quantitative, non-parametric outcome measures, and am looking to see if there is a change in outcomes post intervention. I also have qualitative outcomes, but am not worrying about them yet! I understand that t-tests (and the non-parametric equivalents) can be used for comparing several groups (i.e. if I had a control group as well), but don't know what to do with my single group of participants.


Generate Correlated Normal Random Variables

I know that for the $2$-dimensional case: given a correlation $\rho$ you can generate the first and second values, $ X_1 $ and $X_2$, from the standard normal distribution. Then from there make $X_3$ a linear combination of the two $X_3 = \rho X_1 + \sqrt{1-\rho^2}\,X_2$ then take  $$ Y_1 = \mu_1  + \sigma_1 X_1, \quad Y_2 = \mu_2 + \sigma_2 X_3$$  So that now $Y_1$ and $Y_2$ have correlation $\rho$.  How would this be scaled to $n$ variables? With the condition that the end variables satisfy a given correlation matrix? I'm guessing at least n variables will need to be generated then a reassignment through a linear combination of them all will be required... but I'm not sure how to approach it.


Where can I see my full list of Questions and Answers in my profile page of Stack Exchange Android App?

I want to see all my Questions and Answers in a particular SE site -  - profile page through Stack Exchange Android App. How can I see that? When I tried to see that I found only Top Posts(5) and Top Tags.


How to close aberrant tooltips in Windows

So, here I am, trying to watch The Cleveland Show (TM).      And, as happens from time to time, some program or another has left a modal tooltip.  I don't know which program; how can I lose the tooltip, short of logoff/reboot?  Currently happening on Windows 10, but I have seen it on other versions.


Can a solid object inside the black hole event horizon avoid the singularity?

I will ask this as a simple lay man. Let's consider an astronomical black hole that was creating by in falling matter on a neutron star. As neutron star get heavier it gets smaller and a Schwarzschild  radius corresponding to that mass gets bigger and bigger. At some point, when mass is big enough the neutron star gets smaller than its corresponding Schwarzschild radius then the neutron star disappears behind event horizon.   The Wikipedia article on  says that it can be shown that all mass inside black hole gets concentrated in central singularity. But why? Isn't it possible for a neutron star to live inside black hole, just invisible to us. Yes you might say that neutrons get collapsed, but they can collapse in some other form of matter and there is now a quark ball or some other exotic stuff that makes a solid sphere of some size.  Another source says that all geodesics lead to central singularity. I will make an analogy here. On earth some geodesics point to the center of the earth, If I let go of a stone it will fall towards center of the earth until it hits the ground. So, can matter falling into black hole eventually hit the surface of this neutron/quark/exotic stuff ball inside black hole. What prevent this? Let's assume that there exist some form of matter that resists the pressure of gravity be it neutrons, quarks or something more exotic which we don't know of yet.  EDIT: Although this question was marked as duplicate it is by no means a duplicate of the indicated question. The flagging just demonstrates lack of understanding of both questions.


qgis field calculator truncates column names with more than 10 characters

I am currently working with the field calculator as I want to copy the values from one attribut "join_id" to the attribut "edgeid" within one layerfile. The attribut structure looks like following:  The way I realize this with the field calculator is this:   So far, so good. The values are successfully copied into the edgeid attribut now. But strangely, in the output file of this calculation, all column names which exceed the number of 10 characters, are truncated to 10 characters. Is there a possible way to increase this limitation without changing the name manually afterwards in the properties? In the following, you can see the truncated column names of the outputfile of the calculation:   Any suggestions?


is there any difference between running over a vector using [], like this:  vector<ClassName*> my_vec(10); int N = 10;  for (int i =0; i<N; i++){    cout<<my_vec[i]; }   or, using iterators, like this:  for(std::vector<ClassName*>::iterator it = my_vec.begin(); it != my_vec.end(); it++) {             cout<< (*it); }   except the fact that we neet to keep an updated variable to hold vector size?


distance between a line and a point vector formula

Let $a$ and $b$ be the position vectors of two points $A$ and $B$, and let $p$ be the position vector of another point $P$.  Consider the line through the points $A$ and $B$, and show that the shortest distance between $P$ and this line is given by   $$ d = \frac{|(p-a) \times (p - b)|}{|b - a|} $$   let $r = a + \lambda (b-a)$ be the line connecting $A$ to $B$, my idea was to find a line connecting the point $P$ to $r$ i.e. $r - p$, then projecting this onto the normal of the line which I cannot find. How can I proceed?  I noticed if I cross these $r - p$ and the normalised version of $b-a$ I get the answer. Why?


What is the most intuitive explanation for euler's identity?

Is there any intuitive explanation for: $$e^{i\pi} + 1 = 0$$  About whether this question is a duplicate, what is asked for is not a proof but an explanation that helps with the not-so-intuitive aspects of the identity.


Mac System Preference Screen Saver "Start after:" setting is always disabled

I've been searching for the answer for a while, but I haven't been able figure it out.  I'd like to lower start time of my Mac's screen saver, but it's always disabled, and I cannot make it go up/down.     Any suggestions on how to fix this?  Thanks!


I need the exact config as displayed in the image above. I need to have the entire alphabet showing and I need the title of content to be displayed below the Letter it belongs to. Can we get a detailed explanation on how that can be achieved?


It's not really a typical math question. Today, while studying graphs, I suddenly got inquisitive about whether there exists a function that could possibly draw a heart-shaped graph. Out of sheer curiosity, I clicked on Google, which took me to .  The page seems informative, and I am glad to learn certain new things! Now I am interested in drawing them by my own using Mathematica. So my question is: is it possible to draw them in Mathematica? If yes, please show me how.


Why can't we define linear mapping over vector spaces over two different fields?

When we study linear mapping in the chapter of vector space,  we see that if V and W be vector spaces over the same fields then $T:V\rightarrow W$ is a linear mapping provided it satisfies $ T(a\alpha + \beta)= aT(\alpha)+T(\beta) \forall \alpha, \beta \in V, a\in F$  Now let $V$ be a vector space over the field $F$ and $W$ is a vector space over another field $E$ where $F\neq E$.  My question is,  what problem may arise if we try to define any linear mapping between these two?   The motivation behind this problem was to show there is no linear mapping from $\mathbb{R}(\mathbb{R})$ to $ \mathbb{R}(\mathbb{Q})$  however i am not getting any rigorous path to show this. What i was thinking can we get any kind of contradiction by any way?


Encrypted Home Directory will not generate passphrase

When I run the command ecryptfs-unwrap-passphrase, the passphrase will not appear. I do not know why that is, and I would like some help on this.


Positioning of live chat window on webpage

Where is the best place for a live chat window on a webpage, so it doesn’t hinder the user’s navigation?


is it safe to delete ~/home/{User}/.cache/

IF it's cache it is probably meant to be cleared eventually, but can I just manually delete the whole .cache folder?  It's eating over 10 gigabytes on a 64 GB partition.  I think it is mostly unity game engine and wine.  The os is Manjaro.


Prove that $f(x)\in \mathbb{Z}[x]$ such that $f(0)$ and $f(1)$ are odd has no integer roots

Suppose $f(x) \in \mathbb{Z}[x]$ is such that $f(0)$ and $f(1)$ are odd. How do I show that $f(x)$ has no integer roots?


How to fix "package is in very bad inconsistent state"?

The Synaptic Package Manager shows an error message whose details contain:  E: gnome-control-center-data: package is in a very bad inconsistent state; you should reinstall it before attempting configuration E: gnome-control-center: dependency problems - leaving unconfigured   Please explain what happen in my Ubuntu and how to fix that, thank you


Prove that $$I_{\limsup A_n} = \limsup I_{A_n}$$   To prove this, we need to prove $I_{\limsup A_n}(\omega) = \limsup I_{A_n}(\omega)$, for each $\omega$ in sample space. But I am getting trouble to understand what $I_{\limsup A_n}(\omega)$ implies.  $I_A(\omega)=1$ if $\omega\in A$ and $0$ otherwise.


I’m not sure of whether this is grammatically correct, although I've encountered the same expression many times before.     Most Google searches show it produces 35 times less carbon than the report suggested.   Does 35 times less have a precise meaning in this context, or is it ambiguous here? Does either of these two possibities apply?   the original amount minus 35 times the original amount (35 times less than 100 units would be −3400 units) ¹⁄₃₅ of the original amount (35 times less than 100 units would be  2 ⁶⁄₇ units)


whats wrong with AN??? why i cant animate values inside nodes

Sometimes its works and sometimes doesnt works. I have no idea why. I did same. In left pick is all right. The value changes during the animation. But in right pick is not okay! It just keeps the same value and I don't understand why. I tried several times to press "i" entered different values. Does not work!!!  This is some kind of nonsense.    upd:  Sorry guys. I have never been so butthurt about the blender. It was fixed by itself !!!! I tried closing and opening the blender, creating new files and doing the same node setups. And it did not work! And now I started shooting a video with a demonstration of this bug and it was fixed by itself. I don't understand how to study Animation Nodes if they work on their own. The whole evening I was dealing with this and it didn’t work, and now it’s fixed by itself. I don't understand >_<


Migration of files from Win 10 to Ubuntu

I thought Ubuntu asked for files to import from the along-side operating system on installation. But it didn't, so how can I move them over to Ubuntu after installation?  The files I wanted to import are basically my browsers and bookmarks, along with passwords that are located in Win 10. Both operating systems are on the same computer.


Suppose you have a lot of fuel in your spaceship, in deep space - enough to accelerate at 1mss for a long time. What would happen once you are travelling close to the speed of light? Could you reach the speed of light? Could you go beyond the speed of light by constantly accelerating? What would you observe/experience?


How to Proceed with UK Visitor visa for my family and myself

I stay in US on a valid visa and my wife stays in India along with our daughter who is less than 1 year old. While travelling to US from India, we are planning to visit my brother who has been living in the UK for around 6 years. I am planning to get Visitor visa for my family and myself. Here are the questions I have:   Do I need to fill out , one for myself, one for my wife, and one for my daughter? As I am in the US and my family is in India, will we be able to select different centers (San Francisco for myself and Hyderabad/Chennai for my wife and daughter)?  Do I need to book the flights before submitting the application(s)?


How do I switch the active camera during an animation?

How do I switch active camera temporarily in the middle of an animation? Thank you for the link, yes that is what I'm trying to do. But I'm not having much success. It seems that when I try to bind a camera to markers it binds that camera to ALL markers not just the marker I've selected. Note, I pressed A in between to clear all selected markers, then selected the marker I wanted by right-clicking on it. What might I be doing wrong?  Mark clint dion (apologies if I've got that wrong but I have to do this on a phone, its very fiddly and the part that had your name disappeared when I pressed  edit) yes, I appreciate what you are saying but I'm still very much a novice and I don't have all the terminology yet. I try to be clear but I don.'t always realise other possible interpretations exist which might cause confusion. Please forgive me for that Best, Gary


I am having issue with my trackpad of MacBook Pro Retina early 2015, As it was working properly a day before, the Hardware Keyboard and other things working properly.   I did tried Reseting SMC, PRAM, but no luck, I am on macOS Sierra 10.12.6.  Any suggestions?


Change console font in arch linux to ttf

I have a .ttf font file which I want to use in my arch linux terminal. I followed the instructions for installing fonts on the wiki:   These are the steps I tried:  [root#archserver ~]# cp my_font.ttf /usr/share/kbd/consolefonts/ [root#archserver ~]# setfont my_font.ttf Bad input file size   I am new to Arch so I'm probably missing something, do I need to convert from .ttf to .psf.gz?


Let $\mathrm{M}_{d\times d}\left(\mathbb{C}\right)$  denote the set of all $d\times d$-matrices with complex entries. My goal is to show that the set $\mathcal{M}:= \left\{ \rho\in \mathrm{M}_{d\times d}\left(\mathbb{C}\right) \left|\right. \ \rho\geq0 \ , \  {\rm tr}(\rho) = 1 \right\} $ can be endowed with the structure of a smooth manifold (most likely with boundary).   I have proven that $\mathcal{M}':= \left\{ \rho\in \mathrm{M}_{d\times d}\left(\mathbb{C}\right) \left|\right. \ \rho>0 \ , \  {\rm tr}(\rho) = 1 \right\}$ is indeed a smooth manifold. My argument roughly goes like this:   First we notice that $\mathrm{M}_{d\times d}\left(\mathbb{C}\right)$ is a $2d^{2}$-dimensional real vector space and the set $\mathrm{H}_{d\times d}\left(\mathbb{C}\right)$ of all hermitian $d\times d$ matrices with complex entries is a $d^{2}$ dimensional real vector subspace. In particular $\mathrm{H}_{d\times d}\left(\mathbb{C}\right)$ trivially forms a $d^{2}$-dimensional manifold since it's globally diffeomorphic to $\mathbb{R}^{d^{2}}$.  Next we want to show that the set $\mathrm{P}_{d\times d}\left(\mathbb{C}\right)$ of all positive $d\times d$-matrices (which is a subset of $\mathrm{H}_{d\times d}\left(\mathbb{C}\right)$) is open in the relative topology of $\mathrm{H}_{d\times d}\left(\mathbb{C}\right)$. Therefor it constitutes a $d^{2}$-dimensional manifold. To see this we can consider the map  \begin{align} f: \mathrm{H}_{d\times d}\left(\mathbb{C}\right) &\rightarrow \mathbb{R}^{d^{2}} \nonumber\\ A &\mapsto \left(\lambda_{1},...,\lambda_{d^{2}}\right) \end{align} which maps a hermitian matrix to its eigenvalues. This map is continuous. Since $\mathbb{R}_{>0}^{d^{2}}$ is an open set in $\mathbb{R}^{d^{2}}$ it follows that the preimage  $f^{-1}\left(\mathbb{R}_{>0}^{d^{2}}\right)=\mathrm{P}_{d\times d}\left(\mathbb{C}\right)$  is also open in $\mathrm{H}_{d\times d}\left(\mathbb{C}\right)$. Now consider the map  \begin{align} g: \mathrm{H}_{d\times d}\left(\mathbb{C}\right) &\rightarrow \mathbb{R} \nonumber\\ \rho &\mapsto {\rm tr}(\rho). \end{align} We need to show that 1 is a regular value of g. To do so we pick a $\rho\in g^{-1}(1)$.  Next we choose a curve $\gamma: (-\epsilon,\epsilon) \rightarrow \mathcal{M}$ with $\gamma(0) = \rho$ and $\partial_{t}\gamma(0) = A$ for some $A\in T_{\rho}\mathrm{P}_{d\times d}\left(\mathbb{C}\right)$.  We calculate that  \begin{equation} dg_{\rho}A := \left.\frac{\mathrm{d}}{\mathrm{d}t}\right|_{t=0} {\rm tr}(\gamma(t)) ={\rm tr}(A). \end{equation} Certainly $dg_{\rho}$ is surjective. This proofs the result.  I'm wondering whether this proof can be extended to positive-semidefinite matrices since a positive-semidefinite matrix can be approximated by a sequence of positive definite matrices. I'm however not sure whether the "boundary" that we will obtain is still regular in the sense that it contains no "sharp edges".   I would be more than happy for some suggestions and ideas.


find the trace and the determinant of an nxn diagonizable matrix

can someone help me with the question? your help will be appreciated  Question: if A is a nxn diagonizable matrix, determine tr(A) and Det(A) as functions of eigenvalues of of the matrix?


How do you install Ubuntu on a partitioned drive (B:)?

I wanted to install Ubuntu in my Windows 7 machine in a partitioned drive named 'B:', but if /dev/sda is my primary, what is my partitioned drive then?


$B \equiv 1$ or $-1$ (mod n) where $B$ is the product of the elements of $U_n$.

How to prove the product of the elements of $U_n$ , $B$is congruent to $1$ or $-1$. $U_n$ is the set of all positive numbers less than and relatively prime to $n$. We have to prove $B \equiv 1$ (mod n) where  $B$ is the product of the elements of $U_n$. My Attempt:   We can see the statement is true for $n = 1 , 2$. The number of elements of $U_n$  will be  even for all natural number $n> 3$ as $\phi(n)$  is an even number for all natural number $n \geq 3$. So we will get odd number of elements of order $2$ for each group of order $n(\geq 3)$. $B = b_1 b_2 ... b_k$  where $b_i \in U_n$  and $b_i$ is of order $2$ and $k$  is an odd number for all$n \geq 3$. Now it remains to prove this product is congruent to $1$ or $-1$ mod n. Can anyone please help me ?


Prove the relation between Mahalanobis distance and Leverage?

I have seen formulas on  that relate Mahalanobis distance and Leverage:     Mahalanobis distance is closely related to the leverage statistic, $h$, but has a different scale: $$D^2 = (N - 1)(h - \tfrac{1}{N}).$$    In a , Wikipedia describes $h$ in these terms:     In the linear regression model, the leverage score for the $i^{th}$ data unit is defined as:$$h_{ii}=(H)_{ii},$$ the $i^{th}$ diagonal element of the hat matrix $H=X(X^{\top}X)^{-1}X^{\top}$, where $^{\top}$ denotes the matrix transpose.   I can't find a proof anywhere. I tried to start from the definitions but I can't make any progress. Anyone can give some hint?


I have a Dell E6510 with a Nvidia NVS 3100M graphics card.  Can I plug in a monitor into my displayport and then another into my VGA port and utilize 3 monitors?


How to extract characters from a filename

I have a list which contains file names. How can I get create a new list which contains only the first 4 characters of every line?


Getting a list of files not handled by subversion

I have checked out some files from subversion repository.  After building, there are a number of new files created.  How can I get the list of files that are handled which are not registered with this subversion repository?  I work on linux, and with subversion console version.


I can work out an heuristic argument for $n=2$: (homeomorphically) turning the disc $D^2$ to something like a funnel (no pipe of course), then gradually contracting the open "mouth" of the funnel to a smaller and smaller hole which eventually vanishes (or "heals", if you imagine the hole as a open wound), we have now got an $S^2$.   This argument unfortunately doesn't carry over into higher dimensions. So I think I have to find another approach. Hopefully this simple-looking result $D^n/S^{n-1}\cong S^n$ doesn't entail a dreadfully hard proof. So is there any easy way out or is there any theorem that the result is just a few steps away from? Thanks in advance.


I was always told that the former order is the only grammatical one, however, in one of the videos on Youtube () I encountered the latter order:  "The only winning move is to not play"  instead of  "The only winning move is not to play"  Can this order be used in some instances? When can you do this? What is the meaning of such order?


Bash File Unable to locate package when new line is added

When building a bash file to execute I keep getting an error after adding a new line. I have tried moving some lines around or removing some of the packages but it will results in the same error. In the file if I was to remove 3 and 4 it there will no longer be an error.   E: Unable to locate package <package>   The bash file looks like this   #!/usr/bin/env bash sudo apt update && sudo apt install -y python3-pip build-essential python3-dev python3-setuptools gcc sshpass sudo apt-get install apt-transport-https lsb-release software-properties-common dirmngr sudo apt-get update   The output with the error  Hit:1 http://us.archive.ubuntu.com/ubuntu bionic InRelease Get:2 http://security.ubuntu.com/ubuntu bionic-security InRelease [88.7 kB]                                                   Hit:3 http://archive.ubuntu.com/ubuntu bionic InRelease                                             Get:4 http://us.archive.ubuntu.com/ubuntu bionic-updates InRelease [88.7 kB]         Get:5 http://us.archive.ubuntu.com/ubuntu bionic-backports InRelease [74.6 kB]                                       Fetched 252 kB in 1s (189 kB/s)     Reading package lists... Done Building dependency tree        Reading state information... Done All packages are up to date. Reading package lists... Done Building dependency tree        Reading state information... Done E: Unable to locate package sshpass Reading package lists... Done Building dependency tree        Reading state information... Done E: Unable to locate package dirmngr Hit:1 http://us.archive.ubuntu.com/ubuntu bionic InRelease Get:2 http://security.ubuntu.com/ubuntu bionic-security InRelease [88.7 kB]                                                   Hit:3 http://archive.ubuntu.com/ubuntu bionic InRelease                                             Get:4 http://us.archive.ubuntu.com/ubuntu bionic-updates InRelease [88.7 kB]         Get:5 http://us.archive.ubuntu.com/ubuntu bionic-backports InRelease [74.6 kB]                                       Fetched 252 kB in 1s (209 kB/s)     Reading package lists... Done


$\mathbb{CP}^2$ realizable as boundary of compact smooth $5$-manifold?

As the title says, can $\mathbb{CP}^2$ be realized as the boundary of a compact smooth $5$-manifold?


Doubts of CONSECUTIVE "Unallocated" spaces HD

I have this HD partition.    I want to know:   If it is normal to have two consecutive "Unallocated" space? What sense does it?  You can see I have two:   162.35GB The Right Side of the first Unallocated. (Narrow)    I have another Disk without this LAST Free Space (Unallocated)!!!   I'm NOT asking -how merge consecutive partition?-, I asking if is normal have two consecutive "Unallocated" spaces in HD (is different question).  This  is not answer for my question...


Hotmail is rejecting email from a digital ocean droplet

I have setup my site on Digital Ocean and point the Domain name "A" record to the Droplet IP.  Emails sent by the site are being received in Gmail and other email clients ( SPAM Folder ) but it does not reach at all to outlook.com / hotmail.com email address.  I understand that i have only changed the "A" and "WWW" record of the domain name and now i am sending emails from the droplet, which is somehow not right. What configuration i need to do on the server so the emails sent from my server are trust worthy.   Header of a test email received in Gmail.  Delivered-To: gtemailtesting@gmail.com Received: by 10.182.105.41 with SMTP id gj9csp336738obb;         Thu, 26 May 2016 01:55:41 -0700 (PDT) X-Received: by 10.194.192.10 with SMTP id hc10mr8173424wjc.71.1464252941808;         Thu, 26 May 2016 01:55:41 -0700 (PDT) Return-Path: <register@riyali.com> Received: from riyal.com ([46.101.217.71])         by mx.google.com with ESMTP id wp4si16915971wjb.173.2016.05.26.01.55.41         for <gtemailtesting@gmail.com>;         Thu, 26 May 2016 01:55:41 -0700 (PDT) Received-SPF: neutral (google.com: 46.101.217.71 is neither permitted nor denied by best guess record for domain of register@riyali.com) client-ip=46.101.217.71; Authentication-Results: mx.google.com;        spf=neutral (google.com: 46.101.217.71 is neither permitted nor denied by best guess record for domain of register@riyali.com) smtp.mailfrom=register@riyali.com Received: by riyal.com (Postfix, from userid 1000)     id D27361408BB; Thu, 26 May 2016 04:55:40 -0400 (EDT) To: gtemailtesting@gmail.com Subject: test MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed; delsp=yes Content-Transfer-Encoding: 8Bit X-Mailer: Drupal Sender: register@riyali.com From: register@riyali.com Message-Id: <20160526085540.D27361408BB@riyal.com> Date: Thu, 26 May 2016 04:55:40 -0400 (EDT)  this is a test message   Server Log ( when sent to hotmail):  May 26 05:16:38 riyali postfix/pickup[30639]: E1A1B1408BB: uid=1000 from=<register@riyali.com> May 26 05:16:38 riyali postfix/cleanup[31632]: E1A1B1408BB: message-id=<20160526091638.E1A1B1408BB@riyal.com> May 26 05:16:38 riyali postfix/qmgr[31707]: E1A1B1408BB: from=<register@riyali.com>, size=478, nrcpt=1 (queue active) May 26 05:16:40 riyali postfix/smtp[31634]: E1A1B1408BB: to=<xxx@outlook.com>, relay=mx1.hotmail.com[65.54.188.72]:25, delay=1.2, delays=0.02/0.01/0.53/0.6, dsn=2.0.0, status=sent (250  <20160526091638.E1A1B1408BB@riyal.com> Queued mail for delivery) May 26 05:16:40 riyali postfix/qmgr[31707]: E1A1B1408BB: removed   Server Log ( when sent to gmail ):  May 26 05:25:33 riyali postfix/pickup[30639]: 7D8B91408BB: uid=1000 from=<register@riyali.com> May 26 05:25:33 riyali postfix/cleanup[31719]: 7D8B91408BB: message-id=<20160526092533.7D8B91408BB@riyal.com> May 26 05:25:33 riyali postfix/qmgr[31707]: 7D8B91408BB: from=<register@riyali.com>, size=471, nrcpt=1 (queue active) May 26 05:25:34 riyali postfix/smtp[31721]: 7D8B91408BB: to=<gtemailtesting@gmail.com>, relay=gmail-smtp-in.l.google.com[173.194.65.27]:25, delay=0.84, delays=0.02/0.01/0.35/0.46, dsn=2.0.0, status=sent (250 2.0.0 OK 1464254734 ad7si17051750wjc.239 - gsmtp) May 26 05:25:34 riyali postfix/qmgr[31707]: 7D8B91408BB: removed


what do we say "English Department" or "Department of English"

I would like to know whether these phrases "English Department" and "Department of English" have the same meaning. Is the term "English department" refers to "a department in England" or something else, and whether "Department of English" means the academic place where English is taught? Thanks!


I am stuck on a problem in Fulton's Representation Theory: A First Course. Exercise 3.39 states:  Let $V_0$ be a real vector space on which $G$ acts irreducibly, $V=V_0 \otimes \Bbb C$ the corresponding real representation of $G$. Show that if $V$ is not irreducible, then it has exactly two irreducible factors, and they are conjugate complex representations of $G$.  I had originally misread the problem and taken $V_0$ to be not only a real $G$-invariant vector space, but a representation of $G$ itself. Proceeding from there, I showed that $V= V_0 \oplus iV_0$, but this is clearly wrong, as these $V_0$ is not complex and these two representations are not conjugate. However, given that $V_0$ is only a real $G$-invariant vector space, I'm not sure how to proceed.


i have the following homework problem:  Find the determinant of X(s):  X(s) =  [s, 1, 1, 1], [1, s, 1, 1], [1, 1, s, 1], [1, 1, 1, s]  I know i can exploit the fact that the product of the diagonal gives me the determinant if the matrix is upper, lower or both triangular- but i don't know how i can turn it into a triangular?  If i try regular row operations, i get: X(s) =  [s, 1, 1, 1], [0, s-1, 1, 1], [0, 0, s-1, 1], [1-s, 0, 0, s-1]  This is by first subtracting R1 from R2-4, and then subtracting R4 from R2-3. But i can't get any further, how do i solve this?


Is there a function in python to split a word into a list?

Is there a function in python to split a word into a list of single letters? e.g:  s="Word to Split"   to get  wordlist=['W','o','r','d','','t','o' ....]


A thinking problem of limit from my teacher.

Please find the limit:$$\mathop {\lim }\limits_{n \to \infty } n\left[ {{{\left( {\frac{1}{\pi }\left( {\sin \left( {\frac{\pi }{{\sqrt {{n^2} + 1} }}} \right) + \sin \left( {\frac{\pi }{{\sqrt {{n^2} + 2} }}} \right) +  \cdots+ \sin \left( {\frac{\pi }{{\sqrt {{n^2} + n} }}} \right)} \right)} \right)}^n} - \frac{1}{{\sqrt[4]{e}}}} \right].$$


I'm a third year maths undergrad doing a project on minimal surfaces. However I'm really struggling to understand what the PMT is trying to explain?  Could anyone help explain this (as simply as possible)


Bring back the suggested edit notifications to the top bar

It appears that the suggested edit indicator (to users with the “moderator tools” privilege) has disappeared from the new top bar.  The suggested edit indicator is useful. Suggested edit review is not like other review tasks which can wait until somebody's interested in doing moderation. A pending suggested edit on a post locks the post against modifications by users without the edit privilege. Without the indicator, posts will spend longer in that semi-locked state. That's not good.  Please bring back an apparent notification of pending suggested edits.


How can I show that in a UFD $\operatorname{gcd} (ra,rb) \sim r \operatorname{gcd} (a,b)$?

Let $R$ be a UFD. Let $r,a,b \in R$. Then how can I show that $\operatorname{gcd} (ra,rb) \sim r \operatorname{gcd} (a,b)$?   If $\operatorname{gcd} (a,b) = d$ and $\operatorname{gcd} (ra,rb) = d'$.Then $d|a$ and $d|b$ $\implies$ $rd|ra$ and $rd|rb$ i.e. $rd$ becomes a common divisor of $ra$ and $rb$. Hence we must have $rd|d'$. But I fail to show the converse part i.e. $d'|rd$.  How can I show this? Please help me.  Thank you in advance.


Here i am creating a shopping list, i have a text box to enter the item and submit button to add the item to array. on submit the item gets pushed to array and the the list will get updated.what i am trying to do is when i click on the any of the listed item i should be able to get its id, but i couldn't get it.how can i resolve this?  here is what i have done:    'use strict'; (function() {   var itemslist = [];   $('#addList').click(function(e) {     var item = $('#itemname').val();     if (item == '') {       alert('Cannot be empty!')       return false;     } else {       e.preventDefault();       itemslist.push(item);       update();     }   })    var update = function() {     $('#shopList').empty();     itemslist.forEach(function(value, index) {       $('#shopList').append("
" + value + "
") //list-item gets appended after the successful push of item to array     })   }    $('.items-list').click(function() {     console.log(this.id); //unable to get the clicked element id   })  })(window);
   <form method="post" name="listform">     <input id="itemname" type="text" value="" name="item" placeholder="Ex: butter and milk" required>     <button class="btn btn-peace" id="addList"> Add to List</button>   </form>


Can I re-enter the UK visa free shortly after Tier 2 visa expires?

I lived in the UK for 1 year on a student visa, and then for 3 years on a Tier 2 dependent (spouse) visa. That visa expires shortly and I am not planning to stay in UK, although I will have to go back there for a few weeks.   Can I go back as a tourist? I have an Israeli passport and normally would not require a visa. I read that, in such cases, an immigration officer might not let you in.


unable to install ubuntu in my gatewaylt41p07u

im having a very difficult time installing ubuntu in my laptop (it has no cd port) and i dont want windows on my computer at all. I'm new at this so Im not familiar with the programs or steps i need to take


I can understand that Favorite tags option helps us to highlight the questions on the list with selected tags. I'd like to know if we can add multiple tags to that. For eg., adding java+multithreading should highlight only those question which is both tagged as java and multithreading.


I want to use a PHP variable in JavaScript. How is it possible?


Which of the numbers $99^{100}$ and $100^{99}$ is the larger one?

Which of the numbers $99^{100}$ & $100^{99}$ is the larger? Solve without using logarithms.


Evaluate $\sum\limits_{k=m}^n (-1)^k {n \choose k} {k \choose m}$

By using generating functions and snake-oil I got to    Also what is the implication of $\sum \limits_ {k<={n}}$?   I am told that this is equivalent to:    But I'm not sure how to do that step, thanks for the help!


says that enemies can only cast spells at sorcery speed. Does this prevent spells that are getting cast off of Cascade from casting?


Windows update stuck. Fix It is stuck. So is KB947821. What should I do?

I installed a new computer. After I installed it I updated everything and let the computer run for days. Then I don't know what my daughter did. The computer stopped responding and Windows Update no longer works.  People said to run Microsoft's Fix It tool. Fix It ran but the problem persists and Windows Update still doesn't work. The problem changes though. Before there was an error code. Now Windows Update simply says "Updating" and never ends.  So I downloaded KB947821. It's been 3 hours and it's still installing.       Looks like it hit a firewall or something. I don't see Windows Update on the firewall exception list. However, I've never heard that this is an issue. The firewall only protect against incoming connections, not outgoing right? Or am I missing something?  What should I do?


Privately sharing variable only between two classes - Java

I have a package that contains two classes. Private variable share is located in class A and that variable can be accessed only by these two classes, A and B, and can't be accessed by importing the package. Is it possible to achieve this?  // A.java     class A {     private static String share;  }  // B.java class B {     public String myMethode() {         // do something with share     } }


Show that if $A^{n}=I$ then $A$ is diagonalizable.

Suppose $A$ is an $m \times m$ matrix which satisfies $A^{n}=1$ for some $n$, then why is $A$ necessarily diagonalizable.  Not sure if this is helpful, but here's my thinking so far: We know that $A$ satisfies $p(x)=x^{n}-1=(x-1)(x^{n-1}+\ldots+x+1)$.  If $A=I$ it is clearly diagonalizable so we may assume that $A$ is a root of the other factor.   Edit: Actually, I'm a bit confused and not even sure if we can say that much.  Since the ring of $m \times m$ matrices is not an integral domain, we can not conclude that if $A-I \not = 0$ then $(A^{n-1}+\ldots+A+I)=0$, correct?


what is wrong with below virtual destructor program

class A{ public:    A() { cout << "constructing A." << endl; }    virtual ~A() { cout << "destructing A." << endl; } }; class B : public A{ public:     B() { cout << "constructing B." << endl; }    ~B() { cout << "destructing B." << endl; } }; int main() {     B b;     A *a = &b;     delete a; }  Above example is test code for virtual destructor. It works fine with A* a = new B(); delete a; but fails at runtime when A *a = &b; delete a; Why?


The first one is this: n = int(input()) a = [] for i in range(n):     a.append(int(input()))  The second one is this: n = int(input()) a = [0]*n for i in range(n):     a[i] = int(input())  I have always been using first one, but the second one just came up to my mind. I don't know how append works, but I thought the second one could be more efficient than the first one. Can I get answer of this problem?


Probability of getting any matching pair of 2 cards when x cards are drawn from a deck

A 60 card deck has 4 1a, 1b, 2a, 2b, 3a, 3b, 4a, and 4b cards (32 in total) and 28 blank cards. When x cards are drawn, what are the chances that at least 1 of any of the four pairs are drawn (such as drawing both a 1a and 1b or a 3a and two 3bs). It should be 100% above 44 and 0% below 2.  How do I arrive at the answer to it? I've tried several equations but they've gotten close, not exactly correct.


Can I use the EF 75-300 lens on a Canon T6?

I have only the Canon 18-55mm lens for my 1300D. I want to buy an EF 75-300mm lens. Will I be having a problem using those lenses?


How to get translated picklist value of a picklist field in LWC

Is there any standard capability using method/Api/Wire to get the translated value as per user language in LWC. Regards Stay Safe


How to compile a c program without leaving the editor?

I am using vim editor on Linux mint. I want to know if there is any way to compile c program without leaving the editor.


Safe way to remove excess package directories for other languages

I've reviewed apt, and related pkg commands, but I couldn't find an answer... Is there an option to correctly & safely remove all of these directories in the various installed packages' footprints in the system directories? Some individually are large, and certainly in some it is a lot of excess baggage that should never have been installed, as the install clearly indicates language and keyboard language.


Playing with numbers form $1$ to $n^2$ in an $n\times n$ grid

Suppose we write each number from $1$ to $n^2$ in an $n\times n$ grid exactly once. Prove there are two adjacent cells such that the absolute value of their difference is not less than $n$.   I think it should be a pigeonhole problem, but the work I did so far was basic observations like if we assume all differences are less than $n$, then neither of $1,2,\dots,2n-2$ could be in the row or the column $n^2$ is placed.  Any hints would be appreciated.


Why does GPS positioning require four satellites?

I have a question on the GPS positioning algorithm. In all books I've read for 3D positioning we need four satellites, and I don't understand why.  We need to calculate three variables: x, y, z. We know when satellite send the signal to earth and when we receive it we can measure the time the signal travel to earth by checking the shift in PRN generator. For what purpose do we need four satellite?


How to get non-image (plain) desktop background?

I don't want a background image on my desktop.  Even the color background is a PNG image file.  Want just a RGB color pick, or plain background.  Having a background image makes remote desktop too slow.  Ubuntu v19.04


Valid visa in an expired US passport and an additional renewed passport

I have a valid Indian visa in the US for an expired passport. Additional I have a new US passport. Can I carry both my passports with me when I'm traveling to India? Will I have problems at the immigration at Bombay airport?


Data augmentation techniques for general datasets?

In many machine learning applications, the so called data augmentation methods have allowed building better models. For example, assume a training set of $100$ images of cats and dogs. By rotating, mirroring, adjusting contrast, etc. it is possible to generate additional images from the original ones.  In the case of images, the data augmentation is relatively straightforward. However, suppose (for example) that one has a training set of $100$ samples and few hundred continuous variables that represent different things. The data augmentation does not anymore seem so intuitive. What could be done in such case?


Steroid hormones: how do they travel through the cytoplasm (not just the blood plasma) if they're hydrophobic?

I get that steroid hormones need hydrophilic plasma protein carriers (eg albumin, TBG) to travel in the plasma because they're not soluble in the plasma. However, I don't see any sources talking about how these hormones can then traverse through the (presumably also hydrophilic) cytoplasm to get to their receptors either in the cytoplasm or nucleoplasm. Anyone have any clarifications on this?


About the point $P$ inside a square $ABCD$ satisfying $BP = BC$ and $\angle APD = 90^\circ$

There is a problem I'm trying to solve from the Polish XI Olimpiada Matematyczna Gimnazjalistów. It is question 2 from . (The deadline of 12 October 2015 has passed.)    So far I found $x^2$ and $y^2$ (that are $|AP|^2$ and $|PD|^2$).  In order to prove, that AP=2PD, can I just divide $$ \sqrt{\frac{x^2}{y^2}} $$ and show, that it equals $2$?


Integration-Can anyone give the technique t0 integrate this type of problems?

$$ \int_0^\pi \sqrt{4\sin^2x-4\sin x+1}\;dx $$  Can anyone give the technique t0 integrate this type of problems?  I didn't do this type of problems earlier.


In what way do animals in Minecraft spawn? It looks to me that they spawn more during the night (but where there are torches) and more kind of around you / around some other human player. Am I right, or does it work some other way?  Thank you.


Is there a "list of installed programs"?

Back when I mainly used Windows, I always exported a text file containing my installed programs from the software "CCleaner" before reinstalling my operating system, so that I had a list with all the software I would have to reinstall and not miss anything.  Unfortunately, I can't seem to find such a list in Ubuntu (using Xfce currently, but also just in general). Also, it would be helpful if that list did not include just all packages, such as plymouth, gedit and nautilus, which are installed by defauly anyway, but only those installed by the user.  Is there a way to obtain such a list?


BibLatex Empty Parentheses for No Author | After Author's Name

I am using Zotero to manage my references. Then, I export the .bib file (Biblatex) from Zotero. The issue is there is an empty parentheses if there is no author. Also, if it is a web-page citation, there is an empty parentheses after the author's name.     @online{shotts_learning_nodate,     title = {Learning the shell - Lesson 1: What is the shell?},     url = {https://linuxcommand.org/lc3_lts0010.php},     author = {Shotts, William},     urldate = {2020-12-14},}  The .bib code above results in an empty parentheses after the author's name. @online{noauthor_what_nodate,     title = {What is Linux?},     url = {https://www.linux.com/what-is-linux/},     titleaddon = {Linux.com},     urldate = {2021-01-20},     langid = {american},}       The .bib code above results in an empty parentheses, if there is no author. Here is my LateX code \documentclass[12pt,a4paper]{report} \begin{document} \usepackage[style=ieee]{biblatex} \addbibresource{Exported_Items.bib} \printbibliography[title={REFERENCES}] \include{Chapter1} \include{Chapter2} \end{document}  The result is:  [1] (). “What is linux?” Linux.com, [Online].  Available:https://www.linux.com/what-is-linux/(visited on 01/20/2021).  [2] W. Shotts. (). “Learning the shell - lesson 1: What is the shell?”  [Online]. Available:https://linuxcommand.org/lc3_lts0010.php(visited  on 12/14/2020).  Thank You.


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


Kinetic energy of the object, but Potential energy of the system: Why is it so?

Examples from Principles of Physics (by Walker,Resnick,Halliday) will say it better:     Let us throw a tomato upward. . .as the tomato rises, the work $\mathbf{W_g}$ done on the tomato by the gravitational force is negative as the force transfers energy from the $E_K$ of the tomato. We can now finish the story by saying that this energy is transferred by gravitational force to the gravitational potential energy of the tomato-earth system.   The tomato slows down, stops & then begins to fall back down. During the fall, the transfer is reversed: the work $\mathbf{W_g}$ done on tomato by the gravitational force is now positive - that force transfers energy from the gravitational potential energy of the tomato-Earth system to the $E_K$ of the tomato.      If we abruptly shove a block to send it moving rightward, the spring force acts leftward & thus does negative work on the block, transferring energy from the $E_K$ of the block to the elastic potential energy of the spring-block system. . . .   And many,many other examples. Now, why is the potential energy attributed to the system and the kinetic energy to the object itself? What is the logic/cause?


How do you use a shell other than bash at a terminal as default?

When you drop to the terminal via Applications -> Terminal or Ctrl+Alt+F1 etc. bash is used by default to interpret your commands. If you wish to use another command interpreter (like zsh or fish), how do you get this to start as default?


Insert word with accent into Database using PHP

I try to Insert a word into a database using PHP: for example $productnaam = je t'aime; (I love u in french) This won't work because when updating productnaam I need to put accents arround '$productnaam' like so. Is there any way I can fix this? $query = "UPDATE products2 SET hoofdcategorie1 = '$hoofdcategorie1', subcategorie2 = '$subcategorie2', subcategorie3 = '$subcategorie3', artikelnummer = '$artikelnummer', productnaam = '$productnaam', infotext = '$infotext', hoeveelheid = '$hoeveelheid', eenheidsprijs = '$eenheidsprijs' WHERE id = '$id'";  Kind regards, PJ


Shader turns black when connected to node group

I have a project where I reuse the same material for multiple things. So, I use node groups; saves a lot of trouble - at first!  Up to this problem I have with node groups:  In  you can see, that the logo (white text) is on a black background. This black background should be a node group (and certainly not black).    Here is the Logo Overlay node group:    If I put the node group "ultramarinblau" into the Logo Overlay node group, it does not work!  Only if I add the "ultramarinblau"-node group directly into the Logo Overlay node group, it works:    This behavior is not desired. I'd like to reuse my Logo Overlay node group multiple times with a different node group-input.  What am I doing wrong? Or could this be a limitation of Cycles node groups?  Any ideas are appreciated!


Sorry for my bad English. In Hartshorne’s Algebraic geometry, he defines “abstract variety” on p.104, as follows  abstract variety is an integral separated scheme of finite type over an algebraically closed field $k$  On the other hand, according to proposition 4.10, (in the sense of chapter.1) variety correspond to quasi-projective integral separated scheme of finite type over $k$. Now, is there example of integral separated scheme of finite type over an algebraically closed field $k$ but not quasi-projective.


I'm trying to help my mother find a short story that she remembers reading some, oh, 30 or more years ago.   I don't have a lot to go on, but apparently the main concept of the story was that the food that everyone was eating was said to come from “The Giant Chicken” or “The Great Chicken” kept somewhere (she read it in a Hebrew translation), but when the protagonists delve into the matter, they discover that this “chicken” (as it was translated) is actually a giant cancerous tumor, kept alive and growing for food.  I've established, probably, that this is not Harry Harrison's Make Room! Make Room! or Roommates, the basis for Soylent Green. That was my first thought. I also couldn't find a lead in the  section on wikipedia.  I don't know any more - not what the main characters were, what book it was published in or the actual decade it was written, unfortunately. It would have been read in the early 80's at the very latest.