Hello I am new to programming. I know that you can make multiple ajax calls but I wanted to know what is the limit for AJAX call. Also what are the side effect of making multiple Ajax calls? Also what is there any browser set rule for that?

In Firefox 3, the answer is 6 per domain: as soon as a 7th XmlHttpRequest (on any tab) to the same domain is fired, it is queued until one of the other 6 finish.  What are the numbers for the other major browsers?  Also, are there ways around these limits without having my users modify their browser settings?  For example, are there limits to the number of jsonp requests (which use script tag injection rather than an XmlHttpRequest object)?  Background: My users can make XmlHttpRequests from a web page to the server, asking the server to run ssh commands on remote hosts.  If the remote hosts are down, the ssh command takes a few minutes to fail, eventually preventing my users from performing any further commands.


I have just  in which the OP has not put any effort.  I did not find any rules here  for downvoting spoon feeding answers. Please tell me what should I do? Should I delete my answer?

I came across  answer earlier today, which I deemed trivial (all it gave was the solution, not an explanation of why it worked or how to prevent this from happening in the future, and was practically copied from the comments above, which were posted about two minutes before).   I left a comment explaining why I downvoted, and a few people took offense to it:     @RichardJ.RossIII You're downvoting an answer that answers the OPs question? – modifiable lvalue        @RichardJ.RossIII habitually violates the rules. Since this answer is not wrong or dangerous and is in fact useful, it should not be downvoted. +1 to compensate. – Jim Balter   My question is, is there a policy against doing this? Should we, as a community, accept and encourage such answers? Personally, I think the whole question should be deleted, as it is far from useful, but that's not the point here.  Generally speaking, I save my upvotes for answers which either helped me personally, or do an exceptional amount towards answering a question. I downvote a lot, as I have high standards (that's not to say that I'm perfect, however).  The bottom line is this: should I be more conservative with my downvoting patterns?


How can I upgrade my R installation on Kubuntu 14.4 LTS from 3.0.2 to the current 3.2.4?  Something like  sudo su echo "deb http://www.stats.bris.ac.uk/R/bin/linux/ubuntu trusty/" >> /etc/apt/sources.list apt-key adv --keyserver keyserver.ubuntu.com --recv-keys E084DAB9 apt-get update apt-get upgrade   or a variation of this won't work - R will stay at 3.0.2.

How to install the R language interpreter? What is the package name? I have tried R, rlang, Rlang, rproject, etc. but nothing works - neither apt-get nor Ubuntu Software Centre found R.  Is it possible that R is not included in the official Ubuntu repositories?


Suppose there is a snooker ball rolling on a table. The velocity of the center of the ball is Rω and its direction is horizontally right. I don't understand why the point right below the center on the ball has zero instantaneous velocity. Much obliged if anyone can help me.

They say that for a rolling body, the velocity of the contact point is zero. I'm not getting this. How can it be zero when it's in continuous motion?


How do I generate a random number within a specific range in Groovy Script? I want to generate the number between 10,000 and 90,000  Below are my attempts so far:  1.   Math.abs(new Random().nextInt() % 10000) +90000   2.  (int)(10000 + 90000*Math.random())    Both of these generate a random number yes, but they are not within the range of 10,00-90,000

How do I generate a random int value in a specific range? I have tried the following, but those do not work: Attempt 1: randomNum = minimum + (int)(Math.random() * maximum);  Bug: randomNum can be bigger than maximum. Attempt 2: Random rn = new Random(); int n = maximum - minimum + 1; int i = rn.nextInt() % n; randomNum =  minimum + i;  Bug: randomNum can be smaller than minimum.


I want to get log details between two dates but I am unable to print anything with the command:  egrep "^\[MAY 16 11:00:00\]"  alert.log -A 10000 | egrep "^\[MAY 16 16:30:00\]" -B 10000

I want to extract all logs between two timestamps. Some lines may not have the timestamp, but I want those lines also. In short, I want every line that falls under two time stamps. My log structure looks like:  [2014-04-07 23:59:58] CheckForCallAction [ERROR] Exception caught in +CheckForCallAction :: null --Checking user-- Post [2014-04-08 00:00:03] MobileAppRequestFilter [DEBUG] Action requested checkforcall   Suppose I want to extract everything between 2014-04-07 23:00 and 2014-04-08 02:00.  Please note the start time stamp or end time stamp may not be there in the log, but I want every line between these two time stamps.


I have a TrueCrypt container (around 50GB) which has all of my backups inside.  I'd like to back up the container to cloud storage (not the files within), but obviously, I'd prefer not to re-upload 50GB every time a change is made to the container.  What would be the best cloud storage service for this scenario?  Ideally, I'm looking for a service with block-level updates and doesn't filesync (i.e. not dropbox, which incidentally does have block-level updates).

I have several files that I need to keep encrypted on my home hard disk.  I currently use a TrueCrypt file container, currently around 100MB in size. I need to backup this file daily, and I'm looking for an incremental backup solution.  I read that on encrypted volumes even a small change in a file would change the whole volume and prevent the use of an efficient incremental backup solution. Any ideas how to backup in this case in an efficient way which would allow incremental solution?  I currently use TrueCrypt as my backup solution and CrashPlan as my backup utility, but I'm willing to experiment with alternatives.


Could anyone tell me what I am doing wrong please. I am trying to only use the tikz package. My thought process is that; r^2=x^2+y^2 and r=sqrt(x^2+y^2) so using x=(a/2)+bcos(theta)+(a/2)cos(2theta) and y=bsin(theta)+(a/2)sin(2theta) when r=a+bcos(theta), we get r=sqrt(((0.25)+2cos(theta)+(0.25)cos(2theta))^2+((2sin(theta)+0.25sin(sin(2theta))^2). So rearranging for theta we get theta=acos(r-0.5)*0.5. My code reads:  \documentclass{article} \input{header} \usepackage{tikz} \begin{document}  \begin{figure}[h!] \centering \begin{tikzpicture}[xscale=1.3, yscale=5, domain=-2*pi:2*pi] \draw[->] (-0.2,0) -- (1.7,0) node[below]{$x$}; \draw[->] (0,-1) -- (0,1) node[left]{$F(x)$}; \draw[color=blue,smooth] plot(\x,{0.5*acos({{sqrt((0.25+2*cos(\x r) + 0.25*cos(2*\x r))^2+(2*sin(\x r) +0.25*sin(2*\x r))^2)-0.5}})}) node[below]{$\cos$};  \end{tikzpicture} \caption{Lim} \label{fig:Lim} \end{figure} \end{document}   But it keeps on going wrong. I dont want to use cspolar or any other package.

How would I create a TikZ picture of the limaçon $r=0.5+\cos(\theta)$?   Would I have to convert it to cartesian coordinates or is there a way to plot the polar form?


Most of the time, I have enough power for my Samsung Galaxy SIII to operate for the whole day; at the end of the day my battery charge is about 35%. However, today, the battery died prematurely. I noticed the battery usage screen, and it says that 28% of the battery is used by the Android OS. How could this have happened?  EDIT: My question has been marked as a duplicate, but the target does not have any solution, so those answers do not fully address my question. Though I agree in the fact that this question is the same as the target.

I've read a bunch of forum posts about the Android OS battery drain bug. This is where the 'Android OS' process is showing large percentages in the battery statistics.  For me, I'm running 2.3 Gingerbread. I don't use bluetooth or GPS. I'm on 2G most of the time. Some days I get 40 hours out of a battery. On these days in the battery usage settings, the 'Android OS' process uses about 3% of battery. However other days I get about 8 hours with similar use. On these days the 'Android OS' process uses about 35% of the battery. I really want to find out what causes this.  The fixes suggested so far are:   Reboot (Temporary). Turn off and remove battery for a couple of minutes. Reset battery stats. Change WIFI sleep policy. Use a task manager Flash stuff to the phone. Revert to older versions of the OS (not really a fix).   Does anyone know the definitive cause of this problem and the correct fix? Or is it possible there are multiple issues that cause this so different things will work for different people?  Here are some of the threads:


Background Information  We are using opensource code to manage widgets. One of the pages allows users to edit data in a table that has potentially hundreds of rows. For each row, it's currently populating a drop down box with hundreds of values. As you can imagine, this takes a long time and is not necessary. We won't be editing all rows at a time.   So I've been trying to tweak the code to prevent this from happening. I've changed all the drop downs in the rows to DIV tags and created a new button for them to EDIT a row.  When the user clicks on EDIT, the DIV change to a dropdown menu.  So far so good.  The page loads now in under a second vs over 15 minutes.  Problem  The problem is that when the user clicks on SUBMIT (for that specific row) to save their changes, the DIV field that I've been playing around with is not included in the POST data.  So specifically, the field looks like this when the page loads:
canada
	   but after you click on an edit button and the jQuery that's triggered is done running, it looks like this (as per the F12 developer tool, and NOT view source):       <select tabindex="1" id="location_id" name="location_id">         <option value="0">-- NONE --</option>         <option value="15" style="font-weight: bold">canada</option>         <option value="16" style="font-weight: bold">usa</option>          </select> 	   This drop down is created by cloning an existing drop down menu when the user clicks on the EDIT button for that specific row. (I'm cloning because the existing dropdown has all the values in it that I need.)  I need the form data to include a value of "location_id=15" for the above mentioned example.  What I've checked so far:    I've made sure that the field in question is inside the form tags.  Alternatively, I guess I could create empty drop down controls in each row of my table...and initially set them to hidden.  Then via jQuery, if the user wants to edit the row, I could change the status to visible, and somehow copy all the data from the master dropdown.    Questions  Should the form be able to 'see' fields that are created dynamically by jQuery?  If so, what else could I be doing wrong? If you want to see the full code, let me know and I will paste bin it for you.

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


Can my parents re-enter UK, before completing 6 months outside UK, using a 2 year visa? They have indian passports  1) My parents got UK visa stamped on 16 nov 2016 and Travelled to UK on 9 dec 2017.  2) Then from UK they fly on 6 Jan 2017 to US and are scheduled to fly back from US to UK on 2 July.  This means although they still have their 2 year visa for UK valid, the time lapse between first and second visit to UK is less than 6 months (actually short by only 4 days).   I want to know if this will be a problem. Can find any such thing on Border agency website

I am a US citizen and have recently visted the UK  with simply a passport which allowed me to vist for 6months I have heard rumors that I am obligated to stay in the US for a Equal amount of time that I have visited the UK before I am able to return, but I am struggling tour no any proof of this obligation .. Am I missing somthing or is it simply not true


Tried opening an existing project (created in 2.92) in 2.93 and Blender freezes on render.  Then I discovered that when I reset the program to defaults, cycles is no longer available.  However, it is enabled in Add-ons.  Am I missing something? NOTE: I have tried enabling "filter add-ons" in the Workspace settings, to no avail.  The other topic "why is cycles render engine missing" is not relevant to my issue.

so I'm working on a little bathroom scene and wanted to make a clay render. I started looking for the material override which I kinda knew where it was and on the way I switched my render engine accidently to workbench instead of cycles. Switched to cycles all my seetings on the render tab are missing except color management and free style. Hows that? I restarted blender multiple times and tried some other stuff but nothing changed a thing, and I'd rather avoid a new installation


I'm trying to fix the “the system is running in low graphics mode” problem. When I press Ctrl+Alt+F1 to go to tty1 and login, it goes straight back to the login prompt. Why does this happen and how can I get to the terminal?  Running Ubuntu 14.04.5 on an Asus laptop with nvidia card.  EDIT: After i try to login it says unable to cd to '/home/user'  EDIT2:  $ namei -xl /home/*  f: /home/user $Drw-rw-rw- root root / $drwxr-xr-x root root home $drwxr-xr-x user user user   EDIT3: Thanks for the time and help. I booted Ubuntu from usb and backed up important files and reinstalled Ubuntu. It appeared that all files were changed to root? All directories like: /home /opt were binary and inaccessible files. Only as root I could navigate the directories and copy them to a usb.

I have just upgraded my system but it boots to Low Graphics mode by default. I have seen questions on how to solve this problem and they all suggest to run a couple of commands from a command-line interface.  But there isn't any command-line console by default in Low Graphics mode and hence, I cannot run those commands. And, the answers I saw to solve the problem doesn't explain this situation either.  How to switch to a command-line console in order to run the commands in Low Graphics mode?


So I want a font to be red if a condition is true, but otherwise print in green font. Look at the code down below for an example.  #if Money is greater than or equal to 0, then the font color will be green. Otherwise, the font color will be red.  from colorama import Fore Cash = int(input("Enter random number here (This is how much money a player has)")) print("Money: ", if (Cash) >= 0: Fore.GREEN + (Cash), else: Fore.RED + (Cash))  #this does not work on python, is there a way you can fix this? #If I input a positive number, I get a green font. #If I input a negative number, I get a red font. #The output only says "SyntaxError: invalid syntax"

If Python does not have a ternary conditional operator, is it possible to simulate one using other language constructs?


I am trying to make two dofferent lists in two coulmns of table, but I am getting an error:     something wrong perhaps missing \item   here is my code   \begin{tabular}{cc}        \begin{mylist}         \item text         \item text         \item text         \item text         \item text        \end{mylist} &             \begin{mylist}                \item text                \item text                \item text                \item text            \end{mylist}     \end{tabular}   Thanks for any help.

I'm using this simple code to align date ranges on a CV:  \section{I'm pretty cool}\begin{tabular}{l l} 2009--present & company 1 \\ 2011--2012 & company 2 \end{tabular}   Now this looks like this:  2009 - present   company 1 2011 - 2012      company 2   but I'd like to add a list in each of the entries, like this:  2009 - present   company 1:                    * editor 2011 - 2012      company 2                    * judge                    * jury                     * executioner   How can I achieve this? I could itemize them in a separate column, but it doesn't work inside tabular in cases like this, where I want part of "company 2" to be in that column.


Does the following inequality hold? If matrix $A$ is a $n \times n $ positive semi-definite, $A \succeq 0$, and $U$ is one $n \times k$ unit column-orthogonal matrix ($k \leq n$), $U^{T}U=I$, do we have  $$A \succeq UU^{T} A U U^{T}$$ ?

If $n \times n$ matrix $A \succeq 0$, and one $ n \times q$ column orthogonal matrix $U$, does this inequality hold? $$A- UU^{T} A UU^{T} \succeq 0$$


NB: Nvidia has released an official fix; please see ,  and/or .  Upon waking up Ubuntu 16.04 from Suspend, the following graphical glitches appear around all windows, context menus, and similar:      This is currently known to affect the following NVIDIA cards running the proprietary drivers:  NVIDIA GeForce 610M, driver version 375.39, 340.102 NVIDIA GT 630M, driver version 375.39 NVIDIA GTX 650, driver version 375.39 NVIDIA GT 740M, driver version 378.13 NVIDIA GTX 745, unknown driver version NVIDIA GTX 850M, driver version 375.39, 378.13 NVIDIA GT 940M, driver version 375.39 NVIDIA GTX 950M, unknown driver version NVIDIA GTX 960M, driver version 378.13 NVIDIA GTX 970, driver version 375.39 NVIDIA GTX 970M, driver version 375.39 NVIDIA GTX 980 TI, unknown driver version NVIDIA GTX 1060, driver version 375.26, 375.39, 378.09 NVIDIA GTX 1070, driver version 378.09  The above above list has been sourced from reports from other users here on AU,  thread, and  thread. NB: This is be no means an exclusive list. It probably effects nearly all Nvidia cards.  Furthermore, this issue has been replicated on a clean install where the only change was a software update and the installation of the latest NVIDIA drivers.  What is going on, and how can it be resolved?

After some gorgeous updates I witness this:


Learning JavaScript I ran across two methods to find out whether object has defined property.  Method A if ('propertyName' in object) { } Method B if (object.propertyName) { }   Using console.log() I found out that Method A yields boolean value whereas Method B yields either undefined or value of the property if defined.  Are there any other differences between these two methods or reasons I should prefer using one over another?  If there are no differences I would prefer using Method B since there is no need for using string.

What's the best way of checking if an object property in JavaScript is undefined?


I have a fiber Internet connections. I've tested it at ~50Mb/s. But I downloaded some files on chrome and speed came out around 4-5Mb/s. Why is this so? Please suggest some ways how I can achieve 50Mb/s download speed?

Hi so i just got internet a about a month ago and my net speed is 19MB/s, I have tested it on loads of sites they all say the same thing(19MB/s), but it wont use more than around 2MB/s i have tried downloading different ways, and with more than 1 download at a time and I still get capped at about 2MB/s. It affects everything like loading websites and playing games as well. So if I'm downloading (max 2MB/s) and I load up a web page, every thing slows down, the download speed slows and web sites take for ever to load up, what can it be that makes it thus, and speed test say's 19MB/s


No pun intended! I am trying to use booleans as a way to make a "cage" room for bolts in a bike part, but the problem is i am left with see through holes instead of a partial cut of the geometry.       Since I started out with a cylinder, I figured it had something to do with the mesh not having width (as in non manifold geometry if i got that correctly). But solidify really messes up the mesh so I tried to fix it by closing the mesh with a mirror. Still no luck. Any pointers would be really appreciated.  EDIT: To clarify, I have already looked for double vertices, wrong facing normals and even tried inversing the normals of the cutting object just to make sure. Altho it could be something obvious I' m missing, it's kind of driving me crazy.  EDIT 2: Turns out my object had negative scale which made the normals appear normal. Needed to apply scale and then recalculate them. Thanks to @gandalf3 for pointing me to the right direction.

I'm trying to model an , but it's not going so well when it comes to the magazine of the weapon.   Next to the magazine is a mesh. I want to cut holes in the mag with that mesh. But the magazine just goes invisible or connects with the mesh when trying to execute the Boolean Modifier. I have tested to invert the normals and some other stuff, but it isn't working.


I have a Java test which uses File as follows to access a file:  File localFile = new File("/path/to/my/file/file.txt");   Because Im referencing a file in a particular location I must have that file in my project or the test will fail. Is there any I can generate a File of a specific size as part of my test?   thread uses RandomAccessFile but I don't think that's what I'm looking for.

Is there an efficient way to create a file with a given size in Java?  In C it can be done with  (see ).   Most people would just write n dummy bytes into the file, but there must be a faster way. I'm thinking of  and also of …


My question may seem to be too silly as I am not quite in touch with these things since long, for which I apologise in advance. How should I proceed to calculate the following? $$\sum_{n=0}^\infty\left(\frac{1}{n+1}\right)^4$$

Evaluate $\sum^\infty_{n=1} \frac{1}{n^4} $using Parseval's theorem (Fourier series).   I have , somehow, to find the sum of $\sum_{n=1}^\infty \frac{1}{n^4}$ using Parseval's theorem.  I tried some things that didn't work so I won't post them.  Can you please explain me how do I find the sum of this series using Parseval's identity?  Thanks


I'm trying to use a button that is printed by .html(). I've tried .find() after searching through this site but the onclick event still seem not detected.
div
 <button id="printbtn">printbtn</button>     while the #btntest onclick doesn't show an alert, the CSS on #btntest works. There is something I don't know about elements that are created dynamically?

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


Is there any particular reason why everyone (or at least most people) use the Hogwarts Express to travel to the school?  It seems as though using portkeys or the flu network would be faster and more direct.  While portkeys can be tampered with (as shown in Goblet of Fire), trains could be attacked, have maintenance problems, or be derailed, so they are not infallible either.

To get to Hogwarts, the students had to:   Travel many hours by regular (seemingly non-magical, and fairly slow) train Then get into magical conveyances in Hogsmeade.   The latter makes sense - you can't apparate in Hogwarts.  But WHY oh WHY did they need a regular train?  Why not:   A magic school bus (like Knight one) to Hogsmeade A magic flying dis-illusioned train A bunch of portkeys (heck, they used them to transport the wizards to Quidditch cup in 1994, and IIRC there were a LOT more attendees than students at Hogwarts)! And, at worst, for a couple of Muggle-born students who for some reason can't get to any of the above, arrange something much smaller than a train.


I am trying to match the below text using Regex,  "1bbl" 2bbl "is as" 0.22 "3"   When I match I am not getting the output as expected in my list.  string val = "\"1bbl\" 2bbl \"is as\" 0.22 \"3\""; var reg = new Regex(@"([a-z0-9\s]+)"); Match match = reg.Match(val); List<string> list = new List<string>(); while (match.Success) {     list.Add(match.ToString());     match = match.NextMatch(); }   Current Output:  "1bbl" " 2bbl " "is as" " 0" "22 " "3"   Expected Output:  "1bbl" "2bbl" "is as" "0.22" "3"

I'm new to regular expressions and would appreciate your help.  I'm trying to put together an expression that will split the example string using all spaces that are not surrounded by single or double quotes. My last attempt looks like this: (?!") and isn't quite working. It's splitting on the space before the quote.  Example input:   This is a string that "will be" highlighted when your 'regular expression' matches something.   Desired output:  This is a string that will be highlighted when your regular expression matches something.   Note that "will be" and 'regular expression' retain the space between the words.


For an application that I'm writing, I have a string type variable that I want to display within an ncurses window:   #include <iostream> #include <ncurses.h> #include <string>  int main(){   std::string mystring = "A sample string\n";    // Entering the ncurses window   initscr();   printw(mystring);   getch();   endwin();  }   which throws the following error at compilation:   test_app.cpp: In function ‘int main()’: test_app.cpp:12:18: error: cannot convert ‘std::__cxx11::string {aka std::__cxx11::basic_string<char>}’ to ‘const char*’ for argument ‘1’ to ‘int printw(const char*, ...)’    printw(mystring);   Where am I going wrong? How can I rectify this?

How can I convert an std::string to a char* or a const char*?


Someone said a word, or saying, to me that I didn't know the meaning, so I looked it up.  I cannot remember what it was, but the meaning was:     "Something good comes from something that was bad"   For example, I crashed my car into a beautiful woman's car and we then dated.  Please can someone tell me the word I'm looking for. I think it is two words, each with two syllable's.  Thanks for any help anyone can give.

If someone is the bearer of bad news you might say, Don't shoot the messenger. If you have something that seems unfortunate at first but ends out wonderful you might say it's a blessing in disguise.  I'm looking for a word or phrase that is a combination of the two - a bad experience that is actually bad, but ultimately heralds something good.  For example - if a couple is trying to get pregnant, and the wife gets morning sickness. There is nothing fun about vomiting and nausea, but it potentially heralds wonderful news for the soon-to-be-parents.  Is there an expression to describe the morning sickness?


I need to create custom file extension like myfile.foo  for scripting files how can i configure this ?

Linux determines the type of a file via a code in the file-header. It doesn't depend on file-extensions for to know which software is to use for opening the file.  That's what I remember from my education. Please correct me in case I'm wrong!  Working a bit with Ubuntu systems recently: I see a lot of files on the systems which have extensions like .sh, .txt, .o, .c  Now I'm wondering: Are these extensions are meant only for humans? So that one should get an idea what kind of file it is?  Or does they have some purpose for the operating-system too?


I am using R/RStudio to code a regression (and to optimize the function) over 50+ different variables. For the optimization to work I need to fit a higher order function (I am not sure to what degree I will use).  My question is this: is there a way in R to choose the best variables?

How do you choose a model from among different models chosen by different methods (e.g. backwards or forwards selection)?  Also what is a parsimonious model?


If a ball carrier falls to the ground, and the other team wishes to run the clock because they are leading, how many seconds will the umps allow the clock to run?

I had always thought that when the ball carrier was on the ground, they were down and the play was over. Recently I have seen a fair number of plays such as interceptions or fumble recoveries where the player intercepted (or recovered) the ball and fell on the ground, and then immediately got up and ran for as many yards as possible.  How does this work? Is there a time limit for getting up to resume play?


I have MFC forms program that calls the API inside the DLL and this DLL has both constructor and destructor.  However these constructor and destructor are not exportable which means my MFC forms cannot call t hem.  So if I exit out the MFC program, is that when DLL destructor gets called?  can I choose when to call DLL destructor?  thanks.

Let's say I write a DLL in C++, and declare a global object of a class with a non-trivial destructor.  Will the destructor be called when the DLL is unloaded?


Today I wanted to heat my breakfast in the microwave, when the microwave finished heating my food I pressed the button to open the door, but at that moment the microwave turned again, with the door a little open, then stopped when I opened completely the door. All this happened in a span of 1.5 ~ seconds. I know the exposure was short, but I really want to know if I'm in any danger.

I have noticed that some people press the Stop or Pause button before opening an active microwave oven.  Other people open them right up while they are running, without manually stopping them first.  Assuming that a microwave oven is operating properly, and that it was built in the last quarter-century, are there any real risks with opening a microwave oven without stopping it first?


A modest idea to help accepted answers be "Accepted", might be to script the comments, that if the asker says something like,   Thank you; that solution worked perfectly.   The script would check for this and similar strings, check to see if the user is "New" or has a long history of never accepting answers, and then pop up a small one time ever dialogue stating,   Did the answer provided here answer your question?  Yes | No   And if he clicks yes, scroll the page up, flash the accept answer icon, and ask him to accept it, stating that it helps keep the stack exchange site clean etc~

A lot of times I will answer a question, OP will post "Thanks very much!" And then leave, not accepting the answer that fixed their problem. I know I can just give them a gentle reminder (asking them to consider accepting), and on most occasions I do and they do end up accepting, but the site should be intuitive enough for them to do this by themselves. So when they post "Thank you" or "Thanks" the site could display a tool tip saying to "accept the answer if it helped best".    The message on the image could be changed to be less forceful I guess.


For some reason this is not working, I'm quite new to java so I am probably being naive.  public class CheckScore extends quiz{     public void CheckScore() {         String filename = "Data_CS";{          try (BufferedReader br = new BufferedReader(new FileReader(filename))){             String line;             while ((line = br.readLine()) == "potato") {                 System.out.print("vde");                 System.out.print(line);             }             }           catch (FileNotFoundException e) {                 // TODO Auto-generated catch block                 e.printStackTrace();             }           catch (IOException e) {                 // TODO Auto-generated catch block                 e.printStackTrace();             }        }             } }

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


All I know is that for $x>0$ we have that $f(x)>0$. I do not have any experience with this kind of equations and do not know how to start attacking this problem.

Repeating for the sake of TeX rendering:  Does the functional equation $f(1/r) = rf(r)$ have any nontrivial solutions besides $f(r) = 1/\sqrt{r}$?


can someone help me to convert the following PL SQL code into it's MSSQL equivalent? Thanks in advance.  return to_date(l_date_time, 'rrrrdddhh24miss');

I want to convert a string like this:  '10/15/2008 10:06:32 PM'   into the equivalent DATETIME value in Sql Server.  In Oracle, I would say this:  TO_DATE('10/15/2008 10:06:32 PM','MM/DD/YYYY HH:MI:SS AM')    implies that I must parse the string into one of the , and then convert using one of those codes.  That seems ludicrous for such a mundane operation.  Is there an easier way?


The wikipedia entry for Archimedes' principle (buoyant force = weight of fluid displaced) has interesting formulas explaining why it's true, but is there an intuitive explanation?

Say I have an arbitrary body $\Omega$ and surface $\partial \Omega$ submerged in a hydrostatic fluid of density $\rho$ under the influence of gravity. How does one show ? i.e.  $$\int_{\partial \Omega}(P_0 + \rho g h)d\vec{S}=\text{vol}(\Omega)\rho g\vec{e_2}.$$


How can I install VMware in Ubuntu 13.10? VirtualBox crashes the whole time or doesn't want to work 100%.  I've tried the solution in , but I get errors in terminal when I try the commands.   VMware can me used in the same way as VirtualBox, right? I want to install a different OS inside Ubuntu using VMWare.

I can't install VMwarePlayer 4.0.3 on Ubuntu 12.04 64Bit. For Version 4.0.2, I found a script that I have to run to patch VMware Player for it to work on my system to properly, and after that I could install 4.0.2.  Is there an similar solution for Version 4.0.3?


When I run the following command :  sudo usermod –c "Richard Tracy" dtracy    I get the following error :  Usage: usermod [options] LOGIN  Options:   -c, --comment COMMENT         new value of the GECOS field   -d, --home HOME_DIR           new home directory for the user account   -e, --expiredate EXPIRE_DATE  set account expiration date to EXPIRE_DATE   -f, --inactive INACTIVE       set password inactive after expiration                                 to INACTIVE   -g, --gid GROUP               force use GROUP as new primary group   -G, --groups GROUPS           new list of supplementary GROUPS   -a, --append                  append the user to the supplemental GROUPS                                 mentioned by the -G option without removing                                 him/her from other groups   -h, --help                    display this help message and exit   -l, --login NEW_LOGIN         new value of the login name   -L, --lock                    lock the user account   -m, --move-home               move contents of the home directory to the                                 new location (use only with -d)   -o, --non-unique              allow using duplicate (non-unique) UID   -p, --password PASSWORD       use encrypted password for the new password   -R, --root CHROOT_DIR         directory to chroot into   -s, --shell SHELL             new login shell for the user account   -u, --uid UID                 new UID for the user account   -U, --unlock                  unlock the user account   -v, --add-subuids FIRST-LAST  add range of subordinate uids   -V, --del-subuids FIRST-LAST  remove range of subordinate uids   -w, --add-subgids FIRST-LAST  add range of subordinate gids   -W, --del-subgids FIRST-LAST  remove range of subordinate gids   -Z, --selinux-user SEUSER     new SELinux user mapping for the user account   It states that we can use -c option , then why is it not accepting it my command ? I also see that while creating user and having -c in the useradd command , still I receive the above message and operation fails.  To reproduce the above error , just run sudo useradd dtracy to create a user dtracy with defaults and then try to modify by above usermod command.

ubuntu64@ubuntu:/$ sudo chown –R hduser:hadoop mongodbdata chown: invalid user: ‘–R'   When I try to change the ownership of the file, I am just getting invalid user: '-R' error.


Why is $\lim\limits_{n\to\infty}\frac{3e^n}{n!}=0$?  $e^n=e\cdot e\cdots e$, $n$-times. I tried to find  a constant $C>0$ and a $N\in \mathbb{N}$ such that $\frac{3e^n}{n!}\le C\frac{e}{n}$ for $n\ge N$, to apply the squeezing lemma afterwards. But I don't know how to estimate the fraction $\frac{3e^n}{n!}$, how can I estimate $\frac{3e^n}{n!}$ from above? Thank you.

First I tried to use integration: $$y=\lim_{n\to\infty}\frac{a^n}{n!}=\lim_{n\to\infty}\frac{a}{1}\cdot\frac{a}{2}\cdot\frac{a}{3}\cdots\frac{a}{n}$$ $$\log y=\lim_{n\to\infty}\sum_{r=1}^n\log\frac{a}{r}$$ But I could not express it as a riemann integral. Now I am thinking about sandwich theorem.  $$\frac{a}{n!}=\frac{a}{1}\cdot\frac{a}{2}\cdot\frac{a}{3}\cdots\frac{a}{t} \cdot\frac{a}{t+1}\cdot\frac{a}{t+2}\cdots\frac{a}{n}=\frac{a}{t!}\cdot\frac{a}{t+1}\cdot\frac{a}{t+2}\cdots\frac{a}{n}$$ Since $\frac{a}{t+1}>\frac{a}{t+2}>\frac{a}{t+1}>\cdots>\frac{a}{n}$ $$\frac{a^n}{n!}<\frac{a^t}{t!}\cdot\big(\frac{a}{t+1}\big)^{n-t}$$ since $\frac{a}{t+1}<1$, $$\lim_{n\to\infty}\big(\frac{a}{t+1}\big)^{n-t}=0$$ Hence, $$\lim_{n\to\infty}\frac{a^t}{t!}\big(\frac{a}{t+1}\big)^{n-t}=0$$ And by using sandwich theorem, $y=0$. Is this correct?


I installed Ubuntu 15.10 on virtualbox software, and am trying to connect to the internet witch i can't, it doesn't even show a wireless icons. My original sys is Windows 10. Thanks!

I have a Macbook running Mac OS X, and I have Ubuntu running in VirtualBox.  I am using a public WiFi network on my Macbook, but for some reason my Ubuntu virtual machine won't detect it.  It was able to detect public WiFi networks before, but now it can't.  The network just isn't showing up in the network menu.  How can I fix this problem?


How to prove the equation below:  $(A^TA + \mu I)^{-1}A^T$  =  $A^T(AA^T +  \mu I)^{-1}$  no ideas at all, i major in signal processing and it needs some math techniques so i am not familiar with this part of knowledge, really need help please.

I am reading a book on control theory for multiple input multiple output (MIMO) systems. The author claims that for the identity matrix $I$ and the complex transfer function matrices $G_1$ and $G_2$ (let us assume they are square matrices) the following identity holds: $$(I-G_1G_2)^{-1}G_1=G_1(I-G_2G_1)^{-1}.$$  Is this statement true? And how can I derive it?


I've already proved that continuous functions are symmetrically continuous. Now I want to show that the converse does not hold.  Define $f:X\rightarrow \mathbb{R}, f$ is symmetrically continuous at $x$ So, $\lim_{h\to 0} [f(x+h)-f(x-h)]=0$ I can't come up with a function that's symmetrically continuous but not continuous. Any ideas or hints? The Cantor set comes to mind, but is the Cantor set symmetrically continuous?

Suppose $f$ is a real function defined on $\mathbb{R}$ which satisfies    $$\lim_{h\rightarrow 0}\ [f(x+h)-f(x-h)]=0.$$   Does this imply that $f$ is continuous?   Source: W. Rudin, Principles of Mathematical Analysis, Chapter 4, exercise 1.


So I'm on Ubuntu 14.04 and for some reason every time I use sudo or log in as root I get the following message:  grant@grant-G551JM:~$ sudo apt-get build-dep python-pygame sudo: unable to resolve host grant-G551JM [sudo] password for grant:    It still lets me proceed as if nothing happened, but I get it every time and want to amend the situation. Anyone have any clue as to why this would be?

When I run sudo the terminal is stuck for a few seconds and then outputs an error message. My terminal looks like this:  ubuntu@(none):~$ sudo true sudo: unable to resolve host (none)   What can I do to solve it?


The modern look of windows10 icons is as follow on pictures.  How to get rid of arrows on icons?  UPD: as indicated in question  i did uncheck of file archive property as well applied registry shell icons tweak. now i have  the look as follow:   with ugly blank square in place of arrows. Enterprise windows 10x64 LTSC 1809 17763.379 where the registry branch shell icons does not exists.   look before tweak

On some icons I am seeing a two blue arrows at the top the right pointing towards each other. I first noticed it on the icons on folders which I archived which happened randomly. I archived the folder and the text went blue as expected, then when I went to the folder again the text was black and the folder icon has these arrows. When I just recently installed Office 2007, I noticed the same arrows on the icons for the programs. OS: Windows 10 Pro 64-bit (the latest update: 1115) Application: Microsoft Office 2007 suite and file explorer


I installed Google Chrome from the official repository  stable main  While using it I noticed a strange bug - when I focused on Desktop ( CTRL - SUPER - D ) and then gave back focus to the chrome window the mouse cursor would be around 5px above where it appeared to be on screen and did not match where I was clicking. This affects links as well as chrome interface (menus etc).    When I toggle Chrome window maximization state the mouse cursor works correctly. This issue does not occur on Linux Mint.  Is there a solution ?  GNU/Linux x86_64 4.4.0-22-generic #40-Ubuntu SMP

I have a problem with mouses on my two computers. I will try to describe that issue: When I point some tab in Google Chrome and try to click, it clics a little below... I need to resize Google Chrome window and it works for a while. Second issue is sometimes I can't click on folders on the left corner of desktop. The others folders are OK... Any advices? Regards


Given a nonnegative polynomial $p(x)$ on $\mathbb{R}$, does there exist some $k$ such that for some polynomials $f_1,\ldots ,f_k$ we have $p(x)=\sum_{i=1}^k(f_i)^2$?   I think yes, because of the nonnegative nature of $p(x)$, but am unable to prove. Any hints. Thanks beforehand.

Let $P\in\mathbb{R}[X]$ be a positive polynomial.  I want to show that there exists $A,B\in\mathbb{R}[X]$ so that $P=A^2+B^2$    $\displaystyle P=a\prod_{k=0}^q(x-a_k)\prod_{k=0}^{2p}(x-b_k)=a\prod_{k=0}^q(x-a_k)\prod_{k=0}^p(x^2-2\Re(b_k)+|b_k|^2)$ where $a$ is the leading coefficient, $a_k$ are the real rooks, $b_k$ are the complex roots.  What can i do now ? I know that the identity $(a^2+b^2)(c^2+d^2)=(ac-bd)^2+(ad+bc)^2$ should come in handy, but I can't figure out :  1) How to show that the product real roots is a square  2) How to use the above identity for the complex roots.  If I can solve those two points, then I can solve the problem.


Using Windows 8.1, is there a way to log into my OneDrive account while continuing to log into my machine using my local signin so I can continue access everything on my LAN?  When I open OneDrive it seems to want me to change my machine login.  If I try to install OneDrive for Windows 7, the installation says there is a higher version already installed.  I could not find a way to uninstall the current Windows 8.1 OneDrive.   -rwg

I have  how I can install, or upgrade to, Windows 8.1, without using a Microsoft account, because "I like to keep things separate, and just logon with a tradional local account. Any apps that require me to sign-in with my Live account, will have to prompt me to sign-in".  Until now, I never got around to connect my Windows 8.1 PCs to my OneDrive (formerly known as SkyDrive), which is now baked in to Windows 8.1. Unfortunately, it's apparently no longer possible to use OneDrive, when signing on to PC with a local account:    I can only download the application for Windows Vista, 7 or 8. Attempting to run the installed on Windows 8.1 just displays a windows with the text "Preparing OneDrive for first use" for a while, then exits without allowing me to sign-in.  Just to clarify: I'm of course aware that I would need to sign-in to OneDrive with my Microsoft account, I just much prefer signing in to the application, instead of my PC.  Considering how Microsoft went out of their way, to make it almost impossible to install Windows 8.1 without a Microsoft account, is there some (covoluted) way to make OneDrive sync, without forcing me to sign in with a bloody Microsoft account? How?


After Christian has helped me to solve my prior problem ( - I assumed that this is a new issue and created another question), I am now faced with the situation that it seems that there is a different vertical space between the chapter text of the list of figures and the list of abbreviations.  I've created the following MWE for this case ([oneside]{scrbook} is required by the template I have to stick to and tocloft originates from Christian's solution):  \documentclass[oneside]{scrbook}  \usepackage{tocloft} \usepackage[acronym,nonumberlist,nomain,nopostdot]{glossaries}  \setlength{\cfttabindent}{0em}  \makeglossaries \newacronym{SNA}{SNA}{some nice acronym}  \begin{document}     \tableofcontents     \clearpage     \phantomsection     \addcontentsline{toc}{chapter}{\listtablename}       \listoftables     \clearpage     \phantomsection     \addcontentsline{toc}{chapter}{List of Abbreviations}     \printglossary[title={List of Abbreviations},type=\acronymtype]     \gls{SNA} \end{document}   It seems to be best visible in following picture:    Am I missing something here? Thank you very much again all!

ToC heading is pushed down when using tocloft package – even without any commands written. Leaving it out puts things back in place. Also I noticed the smaller the \document[font-size], the bigger disposition of ToC heading. Is there an elegant way to bring the heading where it should be?  \documentclass[oneside, 10pt]{scrbook}  \usepackage{tocloft} \renewcommand\cftchapfont{\scshape} \renewcommand\cftchappagefont{\scshape}  \begin{document}  \frontmatter \tableofcontents  \mainmatter \chapter{Thank you} This is just great :)  \end{document}


I've just noticed that the syntax highlighting no longer highlights C# "abstract" keyword correctly:        I think it used to work correctly before. Anything changed?

I noticed that sometimes my code gets highlighted in different colors when rendered.   What is syntax highlighting? How does it work? Why isn't my code being highlighted correctly? How do I report a bug or request a new language? How do I use syntax highlighting? What languages are currently available on Stack Exchange?


I was checking code and I came across the following snippet:  int check(char *a) {      (void)(a);//What is this line doing??     return 0; }  int main(void)  {      char *p;     p=(char *)malloc(sizeof(char));     check(p);     return 0; }   What is (void)(a); doing?

int fn();  void whatever() {     (void) fn(); }   Is there any reason for casting an unused return value to void, or am I right in thinking it's a complete waste of time?  Follow up:   Well that seems pretty comprehensive.  I suppose it's better than commenting an unused return value since self documenting code is better than comments. Personally, I'll turn these warnings off since it's unnecessary noise.    I'll eat my words if a bug escapes because of it...


I have a Google Sheet with an input form.  I click the top of a column to highlight the entire column and set format to Currency with two decimal places.  This puts the dollar sign in front of all the previous currency values.  But when I add new lines to the sheet via the form, the new cells do not show the dollar sign.  Is this just a limitation of the Sheets platform, or can I persistently set the Currency format on a column?

I have Google Forms where users enter information, some of which contains leading zeros (e.g. zip codes, ID numbers).   However, when this data is saved to the Google Sheet, it doesn't treat it as plain text and strips the zero. The form fields are text fields with no validation.   I have tried to format the range of cells containing these values as plain text, but it seems Sheets does not set the formatting as plain text unless there is already text in a cell. So I can format a column as plain text, submit the form, and the leading zero will still be stripped.   I tried writing an apps script to deal with this but there's no good way for me to deploy it to the users who would need it.   How can I get around this without having to instruct users to prepend a single quote to their form entry? This is such a small thing, but I can't find a good simple solution to what it seems must be a common problem. If I can't get this to work I may have to drop Google Forms/Sheets altogether.


If $f$ is a continuous function on $[0,1]$ such that for all $t_1, t_2 \in [0,1]$,  $$f\left(\frac{t_1+t_2}{2}\right) \leq \frac{f(t_1)+f(t_2)}{2}$$  Show that $$f\left(\frac{t_1+t_2+ \cdots +t_n}{n}\right)\leq \frac{f(t_1)+f(t_2)+\cdots f(t_n)}{n}$$  I tried proving this statement by induction. I could do this for even $n$.   Let $k=n/2$, then,  \begin{align} f\left(\frac{t_1+t_2+ \cdots +t_n}{n}\right) &= f\left(\frac{t_1 + \cdots +t_k}{n} + \frac{t_{k+1} + \cdots +t_n}{n}\right) \\ &=f\left( \frac{\frac{2}{n}(t_1 + \cdots +t_k)}{2}+\frac{\frac{2}{n}(t_{k+1} + \cdots +t_n)}{2}\right)\\ &\leq \frac{f\left(\frac{2}{n}(t_1 + \cdots +t_k)\right)+f\left(\frac{2}{n}(t_{k+1} + \cdots +t_n)\right)}{2}\\ &=\frac{f(\frac{t_1+\cdots +t_k}{k})+f(\frac{t_{k+1}+\cdots +t_n}{k})}{2}\\ &\leq\frac{f(t_1)+f(t_2)+\cdots f(t_n)}{2k}\\ &=\frac{f(t_1)+f(t_2)+\cdots f(t_n)}{n} \end{align}  However, I don't know how to split should $n$ be odd. One reasonable thing I thought of was to split the middle term. For instance, if $n=3$, We could split it as such $t_1 + 0.5 t_2$ and $0.5 t_2 + t_3$. However, I couldn't find a neat way to carry out the induction if I do it like this. Can someone give a hint?

Given that $$f\left(\frac{x+y}{2}\right)\leqslant \frac{f(x)+f(y)}{2}~,$$ how can I show that $f$ is convex. Thanks.      Edit: I'm sorry for all the confusion. $f$ is assumed to be continuous on an interval $(a,b)$.


I am sending mail to a recipient that is using Outlook.  Normally Outlook opens winmail.dat files automatically. However, this is not happening. Instead he is receiving the winmail.dat file as an attachment. This is probably happening because the email was sent encrypted.  How can he open the ATTACHED winmail.dat file using Outlook?  Note: I have changed settings so that I am sending in plain text format (see below) and he STILL cannot open it (it is still being sent in winmail.dat) so those settings are not working.

Currently I am using Outlook 2010, and sometimes customers claim that they will received an attachment in Windows.dat format.  I have searched online for possible solutions, but mostly the suggestion is to change the sending format to plain text. However, by using plain text format, there is some limitation.  So I just wonder, besides the plain text format, is there a ways to solve the winmail.dat issue?  Besides, does plain text format really 100% avoid the issue?


How to get a closed form for the number of different trees possible for a labeled binary tree with $n$ leaves labeled from $1$ to $n$? I have derived a recurrence formula, but unable to find a way to solve it. My formula is : if there are $n$ terminal nodes in the tree, then T(n)=$\frac{1}{2} \sum_{i=1}^{n-1} \binom{n}{i} *T(i)*T(n-i)$ The result should be a closed form equation, like $T(n)=\frac{(2n - 3)!}{2^{n-2}(n - 2)!}$ It is different from Catalan number. Explanation: For $3$ terminal nodes, number of possible trees is $3$. These are :    However following trees are equivalent, and counted only once:

To form a rooted binary tree, we start with a root node. We can then stop, or draw exactly $2$ branches from the root to new nodes. From each of these new nodes, we can then stop or draw exactly $2$ branches to new nodes, and so on. We refer to a node as a parent node if we have drawn branches from it.  This diagram shows all distinct rooted binary trees with at most $0,$ $1,$ $2,$ or $3$ parent nodes:   (Note that, in the diagram, the roots are at the top and the branches extend downward -- somewhat contrary to what you'd expect for something called a "tree"!)  Prove that the number of distinct rooted binary trees with exactly $n$ parent nodes is the $n^{\text{th}}$ Catalan number.    To count the number of rooted binary trees, I think you do something with a power of 2, because there's two choices at each point.  But that's all I have.  And for the Catalan numbers, which is $C_n = \frac 1{n+1}\binom{2n}n,$ and I don't understand the other recurrence, if you could explain that, it would be great.  Can someone walk me through this problem?  Thanks in advance!


I just deleted a file and I want to recover it. I have seen many similar questions in here suggesting using Photorec but this recovers everything and has an estimated search time of more than 4 hours in my case.  I just want to find a specific file by using its name. Is that possible with Photorec or other software?

I was working on a LibreOffice Writer document when my computer turned off. No problem there, I booted up, went back into LibreOffice and it gave the option to recover everything. I left the document up on my computer and a family member came by, closed it and hit Don't save. I had never officially saved it yet I believe.  I see that by going to .config/libreoffice/4/user/backup, it looks like I can view LibreOffice documents that are being "autosaved" until I officially save them (or "don't save" them). That leads me to believe it may be possible to recover this document since it was at least autosaved there before. Would I just go to advanced options in testdisk, and from there select the large partition (I only have one SSD), and then read through the list? Will testdisk pay attention to these autosaved LibreOffice documents that were temporarily in a backup folder until the user decided to oficially save?


It's happand after the laptop is accidently shutdown when battery is dry. Theb when I try to start the laptop it  always show blank purple screen.  So I tried to select option "advance option" then select recovery. But the terminal show this:  ubuntu busybox v1.22.1 initramfs uuid xxxxx not exist

I am running an HP pavilion dv6000 dual boot win7 and Ubuntu 12.04. (well, up until today).  After a reboot, the boot process drops to the BusyBox shell and I end up at the prompt:  BusyBox v1.18.5 (Ubuntu 1:1.18.5-1ubuntu4) built-in shell (ash) Enter 'help' for a list of built-in commands.  (initramfs)   I've been researching others who have had this same problem, but haven't been able to find any of those solutions to work for me.  I tried the method described , and after the final command   mount -t ntfs-3g /dev/sda1 /root -o force   it does nothing and gives me another (initramfs) prompt.  I can boot to a live CD (USB) and get to a terminal, but it doesn't seem to do much good, as I can see the /dev/sda1 in the ls command, but it doesn't recognize it when I try to cd to it.  One more question: using the command fdisk -l how can I tell which mount point (sda1/sda2) is my windows partition and which one is Ubuntu?


I'm creating a simple flowchart using Tikz, and I'd really like the "decision" nodes to be lozenge-shaped (think "tilted parallelogram") rather than square, in order to fit text better.      Here's a minimal example, which is only the top part of the flow-chart and so doesn't illustrate the worst of the node in terms of text fit, but does show what I've got as opposed to what I would like, which is the "decision" node shape here:     \documentclass[a4paper]{article}  \usepackage{amsmath}  \usepackage{tikz} \usetikzlibrary{positioning} \usetikzlibrary{shapes.geometric} \usetikzlibrary{arrows,automata}  % Define block styles \tikzstyle{decision} = [diamond, draw, text width=10em, text badly centered, node distance=3cm, inner sep=0pt] \tikzstyle{line} = [draw, -latex'] \tikzstyle{cloud} = [draw, ellipse, node distance=3cm]  \begin{document}  \begin{figure} \begin{center} \begin{tikzpicture} % Nodes   \node[cloud] (a) {$p_n$ is proposed.};   \node[decision, below of=a] (b) {Has a positum $\phi$ been admitted?};   \node[decision, below left of=b] (c) {Is $p_n$ true?};   \node[cloud, below right of=b] (g) {Nothing happens.};  % Edges   \path [line] (a) -- (b);   \path [line] (b) -- node {no}(g);   \path [line] (b) -- node {yes}(c); \end{tikzpicture} \end{center} \end{figure}  \end{document}

I am very new to the TikZ package, and I need to draw some flow chars by using the following shapes.   However I couldn't figure out how to draw the 4th and and 6th ones below. It would be very nice (for completeness) to help with all of the shapes in the list below.      Your help will be greatly appreciated.  Note: I have visited  but it contains some other shapes.


I have this problem with the Danish letters ÆØÅ. I use the following script to arrange posts alphabetically when loading the page.  if($stmt=$mysqli->prepare("select `titel` from `ann` order by `titel` asc "))      {     $stmt->execute();     $stmt->bind_result($titel);     while($stmt->fetch())         {         $letter=substr($titel,0,1);         $res[$letter][] = array('titel' => $titel);         }          foreach($res as $key=>$val)         {         ?>         <div class="<?php $letter;?>">
         <?php         echo "
$key
";         foreach($val as $reqvals)             {             echo $reqvals['titel'];              }         }     $stmt->close();     }     Unfortunately, the script is unable to handle the 3 Danish letters, which are in the end of the alphabet. They are placed first - before "A" hen loading the page.   � Åben dialog......  A Altid klar Astrids hemmelighed  B Bravo Klaus  D Den hemmelige klumme   How can I fix this?

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


Does there exist a continuous function $$f: \mathbb{R} \rightarrow \mathbb{R}$$ that is rational at (Lebesgue) almost every irrational, and irrational at every rational?  Some thoughts: for some $q\in \mathbb{Q}$, $f^{-1}(q)$ is a closed set of positive measure disjoint from the rationals. But of course that's possible.  Though it does at least mean that the null set of irrationals where $f$ is irrational is dense in $\mathbb{R}$, by the Baire Category theorem, since the set is the complement of the countable union of nowhere dense sets: $$\big(\mathbb{Q}\cup(\cup_{q\in\mathbb{Q}} f^{-1}(q))\big)^c$$  Also if it exists, $f$ can't be injective on any open interval. So the Cantor function comes to mind, but that obviously doesn't work since it's locally constant on an open set. Maybe a "nowhere injective" function is guaranteed to be locally constant somewhere?  I have no idea.   (I saw this asked on reddit, and after thinking for a while I'm too curious not to ask here.)

Does there exist a continuous function such that f(x) is rational for every irrational x, and f(x) is irrational for every rational x? I can think of examples where this would be true, but I'm having a lot of trouble with the continuity.


I am trying to read a string from a keyboard and store it in a character pointer. But it doesn't seem to work. Can someone please help me out. Here is the code.  char *city = "Bangalore"; char *state; state = city;  printf("Enter your state : "); scanf("%s",state);   // I get Bad access here.   but doesn't crash when I use this.  char city[] = "Bangalore"; char *state = city; printf("Enter your state : "); scanf("%s",state);

The following code receives seg fault on line 2:  char *str = "string"; str[0] = 'z';  // could be also written as *str = 'z' printf("%s\n", str);   While this works perfectly well:  char str[] = "string"; str[0] = 'z'; printf("%s\n", str);   Tested with MSVC and GCC.


There are $n$ seats in a classroom and $n$ students who have been assigned seats on small slips of paper. Unfortunately, the first student to enter the classroom has lost his slip, so he just chooses a seat at random and sits in it. Each of the remaining students enters one at a time and either sits in their assigned seat if it is empty or if someone is sitting in their seat, chooses a seat at random from those that are empty. For $n\geq 2,$ show that the probability that the last student to enter will sit in their assigned seat is $\frac{1}2.$  I tried a few small examples and drew some tree diagrams to list out the possibilities, and got $\frac{1}2$ each time. I did make a few obvious observations though. Firstly, if the first student sits in the right spot, everyone else will too, by the premise. There is a $\frac{1}n$ chance for this. Secondly, if the first student chooses the last person's seat, the last person won't be able to sit in their assigned seat. And thirdly, the only way the last person can sit in their assigned seat is if everyone before him/her did not choose his/her seat. We can label the students $S_1,\cdots, S_n.$ I'm not quite sure how to determine the sample space for this problem (i.e. the total set of points or possibilities to consider).

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


Update computer to latest version but the version we have is 8.10 and it is not upgrading to version 13.10. I message I see is "server error". I dont know how to update in another way.

Recently I have installed an older version of Ubuntu on my old machine. Whenever I try to install any software, I get an error saying it couldn't be found:  $ sudo apt-get install vlc Reading package lists... Done                Building dependency tree        Reading state information... Done     E: Couldn't find package vlc


I'm working on a map in the print composer window of QGIS, with an inset map showing a larger extent and highlighting the area of my main map as an overview. Everything looks good in the print composer, but when I save as a pdf or image, or print as a pdf, the inset map stays the same in the print composer but the inset map on the pdf has totally shifted position and scale. I have the layers and styles for the map item locked.

I'm having trouble with the OpenLayers Plugin of Qgis and the map composer:  If I create an OSM-background layer and if I want to export this, the OSM-Layer looks perfectly all right in the normal qgis program window. But in the map composer and after export the layer has shifted relatively to my other shape layers (EPSG:32633 - WGS 84 / UTM zone 33N).  The second thing is that the output resolution of the exported osm-layer is very, very poor.   A really bad way of getting around this whole trouble would be to increase the screen resolution and make a screenshot of the map composition window of qgis. But I don't think this would be very professional. It also would cause a lot of pain :)   I'm using Qgis 1.8.0-Lisboa under Linux. The openlayers plugin is version 0.92.


I'm trying to solve the logical problem above, but can't seem to figure it out. Any help would be greatly appreciated!

Inference rules allowed are: $\lor$, $\wedge$, $\rightarrow$, $\neg$ introductions and eliminations.  In question, it says I am allowed to make use of a lemma or equivalence as long as I provide a proof of it by natural deduction too. (I will come to that soon enough, hopefully.)  First of all, that "$,$" between $p$ and $p \rightarrow (r \rightarrow q)$ made me a bit confused, but I ended up assuming that comma just splits two premises we are given. I tried to not dig too much and proceeded to make proof, however I got stuck after using implication elimination on $p \rightarrow (r \rightarrow q)$ and obtaining $(r \rightarrow q)$. From there on, I have a sense that I will just use 4-5 more steps and reach $(\neg q \to \neg r)$ but I just couldn't figure it out.  Then I realized that I can make use of equation $p \rightarrow q \equiv \neg p \lor q $ .  As stated in question, I tried to prove this equation by natural deduction (I know at this point I am just making things harder than it is supposed to be, but what the heck..)  This is the proof I tried to make in fitch style:    If you realize I am using double negation here and I am not even sure if that is even allowed to use.  From here, I just needed to show that $(r \rightarrow q) \equiv (\neg q \rightarrow r)$ knowing $(\neg r \lor q) \equiv (\neg \neg q \lor \neg r)$ and that is $(\neg r \lor q) \equiv (q \lor \neg r)$   But if you realize, that means I will have to prove double negation law "$\neg \neg q \equiv q$" as well as commutative law "$(\neg r \lor q) \equiv (q \lor \neg r)$". Like these extra two small proofs are not enough, I also have to use them with proper notation/syntax in latex aside with fitch style proof tables.  This makes me realize that it is definitely a bad idea to make this proof by natural deduction using these "transformation" equivalences if I may call them that.   So, I think I need to give up on that idea and stick to direct proof with implications.  However, as stated above, I am stuck after implication elimination. Could you guys help me figure it out how to move forward from there?  P.S: Reason I state all those unnecessary steps is that, I think it is just more appropriate to not just "ask for a direct answer" but provide my thought process. Another challenge of doing this proof for me is that having to use fitch style proofs in latex. I just can't figure out where to place that "p" before comma in the question. Anyway, enough confusion!


My question is on the title. I want to make arrow pointing at suncross like ? I can make the arrow by myself can you help me to make the suncross?

How do I do this in TikZ:  I want to draw a circular node with a cross in it to resemble a multiplier like in the diagram shown in the link below. I can draw a circle but I don't know how to put the cross inside.


I want people to enjoy the show. or I want  people enjoying the show.  Is it possible to use both?

Some verbs are followed by ing, e.g. I enjoy swimming. We can't say I enjoy to swim. Likewise, some verbs are followed by to, e.g. I decided to make a plan.   Which particular verbs are followed by ing and to? Can you please provide a list for that?  Moreover, which verbs can be followed by both without having the meaning changed?


Let $a_1$ be an integer. Then we assume        $$ a_{n+1} = \begin{cases} 3a_n+1,&\text{$a_n$ is odd}\\ \frac{a_n}{2},&\text{$a_n$ is even} \end{cases} $$   Now we prove that     for any $a_1\in\mathbb N$, there exists $N$ which satisfy: $a_n=1,2$ or $4$,$n\geq{N}$.   At first I want to give it a suitable category for the problem: analysis. And I want to use the basic method: evaluate the upper bound for $a_n$, however I find it's not easy because the iteration is rely on the odd or even property of $a_n$. So I attempt the method of number theory. But I failed to find any way to go over it. Can anyone have idea? Thank you.

I have been fascinated by the  since I first heard about it in high school.     Take any natural number $n$. If $n$ is even, divide it by $2$ to get $n / 2$, if $n$ is odd multiply it by $3$ and add $1$ to obtain $3n + 1$. Repeat the process indefinitely. The conjecture is that no matter what number you start with, you will always eventually reach $1$. [...]      Paul Erdős said about the Collatz conjecture: "Mathematics is not yet ready for such problems." He offered $500 USD for its solution.   How important do you consider the answer to this question to be? Why?  Would you speculate on what might have possessed Paul Erdős to make such an offer?  EDIT: Is there any reason to think that a proof of the Collatz Conjecture would be complex (like the FLT) rather than simple (like PRIMES is in P)?  And can this characterization of FLT vs. PRIMES is in P be made more specific than a bit-length comparison?


I want to remove the day field from a Date dropdown of a webform. How to do that? I tried with hook_form_alter() without success. Any suggestions? Thanks

Using a 'date' field in the FormAPI, is there something I can set to hide the day field from showing?


This is a simple program to calculate an answer but after rounding off upto 2 decimal places for loop is giving wrong results. #include <iostream> #include <iomanip> using namespace std; int main() {     int t;     cin >> t;     float a, b, c, d;     while (t--)     {         cin >> a >> b >> c >> d;         float speed = (a * b * c * d);         float ans = (100 / speed);         ans = (int)(ans * 100 + .5);         ans = (float)ans / 100;         cout << ans << endl;         if (ans >= 9.58)         {             cout << "NO" << endl;         }         else         {             cout << "YES" << endl;         }     }      return 0; }  input 3 1.0 1.0 1.0 10.45 1.0 1.0 1.0 10.44 1.0 1.0 0.9 10.44  output 9.57 YES 9.58 YES 10.64 NO  As seen in second testcase the if statement for value 9.58 is giving yes as output but should gives no.

Consider the following code:   0.1 + 0.2 == 0.3  ->  false   0.1 + 0.2         ->  0.30000000000000004   Why do these inaccuracies happen?


Let $X$ and $Y$ be Riemann surfaces (not necessarily compact) and $f:X\to Y$ a holomorphic map. A point $x\in X$ is said to be a ramificiation point of $f$ if the multiplicity of $f$ at $x$ is $\geq 2$. The set of all ramification points of $f$ is a discrete subset of $X$. A point $y\in Y$ is said to be a branch point if it is the image of a ramification point. Why does the set of branch points form a discrete subset of $Y$? (This is asserted in p.46 of Miranda's Algebraic Curves and Riemann Surfaces. If $X$ is compact then this is obvious because there are only finitely many ramification points. But I can't handle the general case.)

I refer to , which I understand says that the branch points of a nonconstant holomorphic map $F: X \to Y$ between Riemann surfaces $X$ and $Y$, both of which are not necessarily compact, form a discrete subset of range $Y$ of the map $F$. (Not sure if 'connected' is part of the definition of Riemann surfaces in other textbooks, but it is here.) Question 1: Do I understand correctly, and is this indeed true? What else I understand:  $A$ is a discrete subspace/subset (I just assume everything here is the usual subspace topology) of $B$ if and only if every singleton subset of $A$ is open in $A$ if and only if every point of $A$ is isolated.  This overflow question () seems to suggest this is not true but is true if $F$ is proper. However, I'm not sure the definitions of Riemann surface are the same (maybe some answers use definitions where Riemann surfaces are not necessarily connected or something).  2.1. I know $F$ is 'discrete' (meaning that its fibres are discrete; here, i refer to a ): see definition before Lemma 3.1, on p. 7), by Proposition II.3.12, and open, by open mapping theorem, which is Proposition II.3.8, but I'm not sure these help show $F$ is proper or are otherwise helpful. Ostensibly 'discrete' maps don't map discrete subsets to discrete subsets.   This stackexchange question () seems to suggest this is true.  I think this is true if $F$ is injective or at least something like locally injective. (Please don't make me type up all the stuff I did for this part.) However based on the question in (3) and based on the , which I think uses the term 'branch points' to mean the same thing as what Miranda means by 'ramification points' (and thus is different from Miranda's 'branch points'), it seems that no neighbourhood $U$ of a ramification point $p \in U \subseteq X$ of $F$ is such that the restriction $F|_U$ is injective.  Kinda related:    This page () says    Now, the ramification and branch points must form a discrete set  I don't think the page assumes anything like $F$ is proper.  The  text in (2.1) actually seems to assume proper based on the '3.7. Proper holomorphic maps' part, but said part refers to 'Lemma 3.17', so I think proper can be replaced with closed. Maybe $F$ is closed or something.  Kinda related (see Question 2 below):     says    If $F$ is proper then the image $\Delta = F(R)$ is discrete in $Y$.   This seems to have all the same assumptions as with Miranda. Ostensibly, either Miranda is wrong or there's some higher level machinery that allows us to omit $F$ proper.  Question 2: To possibly generalise this, what are the minimum requirements on $F, X$ and $Y$ to make $F$ map discrete subsets to discrete subsets? I mean, I'm not sure we really need 'holomorphic' here. I have a feeling this applies perhaps to maps that are just open/closed, continuous and discrete and spaces that are just Hausdorff and locally compact or something.  (again) Kinda related:


I just installed Ubuntu 15.04 on an older computer because it could not handle many of the features included with Windows Vista. I thought I would try Ubuntu to improve performance. However it isn't running any better. Is there a way to remove some of the less important features of the Ubuntu O.S. to improve the performance of this older computer?

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


Why is the statement "An inflection point can not be a local extreme point?" wrong? Isn't a local extreme point either a max or a min only? What is wrong here?

Can anyone find a function $f$ with an $x$ such that $f'(x)=0$, $f(x)$ is either a relative max/min and $(x,f(x))$ is an inflection point? In other words, suppose you're using the second derivative test, see that $f''(x)=0$ and then note that it's actually an inflection point. Can you conclude that $(x,f(x))$ is not a relative extremum?  It's easy to find an example where $f''(x)=0$ and there is an extremum--take $f(x)=x^4$, but in that case, there isn't actually an inflection point at 0.  I'm certainly open to the possibility that an inflection point can never be an extremum, though it seems like something I ought to have discovered by now, were it true.


I just made a minecraft server and was wondering if in the server it would be possible to change a player's gamemode when they visit someone else's building(s) (this excludes the owner of the building).  I used the /testfor command but I'm not sure how to select a specific land and change the game mode of the player on it.

Is there a way to set an "Adventure Mode Boundary" in Minecraft?  I am trying to create this village where players can spawn in, and then set out to explore the world and build and do normal minecraft stuff. I don't want them to destroy this village, so I want them to be in adventure mode when they are in the village and then switch them to survival when they leave, and vice-versa. When they return to the village, they get switched back to adventure mode.  In other words, I want to set an "Adventure Mode Boundary" to protect buildings. I am working without mods. I am hoping there is an simple way using command blocks.


I am unable to create an inner class object in java:  package OOO;  class Car{     class Engine{          void display() {             System.out.println("this is inner diaplay() method");         }      } }  public class Sample8InnerClassCar {     Car c = new Car();     Car.Engine e = c.new Car.Engine(); }   its throwing me an error : cannot allocate member type Car.Engine. could someone please help me to understand more?

What is the main difference between an inner class and a static nested class in Java? Does design / implementation play a role in choosing one of these?


I have a railway reservation in sleeper from Jaipur to Pune and boarding point at Ratlam. Will I be allowed to take my seat at Ratlam OR the TT will cancel it and allocate to others?

I have booked a ticket on a train from Mumbai to Chennai and boarding at Pune. Since my schedules have changed, I will be in Mumbai on that day. Can I board the same train in Mumbai in my own ticket and claim the seat/berth?


As per the picture, the fire/smoke is not showing up with the blender internal renderer. Is this a common issue?  Are there any obligatory steps to make it show like it does in the preview?  Thank you.

When I try to run the smoke simulator in Blender 2.62 I get no smoke at all. When I attempt to render, the only output is a black screen. What am I doing wrong here that is making the smoke simulation not render?  Is it a mistake I made, or a problem with Blender version 2.62?


I saw  and it states that the Lie algebra of the special linear group $SL_n(\mathbb C)$ is the group of traceless matrices $\mathfrak{sl}_n$.  I know the definition of a Lie algebra: given a matrix group $G \subseteq GL_n(\mathbb K)$ its Lie algebra is defined to be the tangent space at $I$.  From this definition it is immediately clear what dimension the Lie algebra has to have.  What is unclear to me is:      Assuming I don't already know the answer, how do I arrive at the insight that this tangent space is traceless matrices?   I skipped through Tapp's book in search of hints and found that the exponential map is a homomorphism from the Lie algebra into the Lie group. I also found a lemma that states that   $$ \det e^A = e^{\mathrm{trace}(A)}$$  That is unfortunately only half-useful: If I already know what the Lie algebra is then this lets me prove that the image of the Lie algebra under the homomorpism defined by the exponential map is indeed in $SL_n$.   So it's kind of not so useful. Surely there must be geometric insight?

I'm studying Lie algebras as purely algebraic objects, without much of a background in the differential geometry surrounding Lie groups.  The definition of  $\mathfrak{sl}(n)$  has been given to me as the algebra of traceless $n\times n$ matrices with multiplication $$[A,B]=AB - BA$$ With my limited knowledge of differential geometry, I roughly understand that $\mathfrak{sl}(n)$ is defined as the tangent space of the Lie group $SL(n)$ at the identity, but I don't see how this leads to the definition of $\mathfrak{sl}(n)$ as the traceless $n\times n $ matrices.  I was hoping that someone would be able to roughly explain (or point me in the direction of a not-too-differential-geometry-technical article):     1) What is the reason $\mathfrak{sl}(n)$ is taken to be the algebra of traceless $n \times n$ matrices?       2) What is the connection between $\mathfrak{sl}(n)$  and $SL(n)$?      3) What is the motivation for this definition?


Your carbon footprint is the total carbon sum of your actions, be it when you travel, when you shop, when you eat, when you bathe - any action that uses up fossil fuels such as oil, coal or gas. []   What does "be it" mean in the above context. What can be use instead of "be it" there? I need some simple example to understand that usage of "be it".

What does be it mean in this context and what kind of sentence is this? (grammatically)     There is no one in our society who is not ethnocentric to some degree, no matter how liberal and open-minded he or she might claim to be. People will always find some aspect of another culture distasteful, be it practices, a way of treating or relatives, or simply a food that they cannot manage to get down with a smile.


I currently have python2 installed on my machine. Is it possible to have both python2 and python3 installed on the same machine? If so, how?  Thanks!

I'm running Windows and the shell/OS automatically runs Python based on the registry settings when you run a program on the command line. Will this break if I install a 2.x and 3.x version of Python on the same machine?  I want to play with Python 3 while still being able to run 2.x scripts on the same machine.


I want to blow up some old prints of my children. They were taken 15 years ago on a Nikon camera. I want to blow them up to 30x40" but the photo lab gives me the warning that the resolution is not high enough for a good quality print.   So I looked into maybe ordering the "blow up 3" app, which also means I need to get a subscription to Photoshop. I would be okay with all this investment if I were sure that it would result in good quality blow ups, but I'm not sure. Does anyone have any advice for me? I'm not a photographer at all, but I've taken some awesome photos in my past!

I want to enlarge an image to a bigger size. This will cause pixelation.  So I want to apply some treatment to it in Photoshop that will suppress some of this pixelation. Of course I cannot generate new pixel information, only smoothen it etc. so that the pixelation is not so much apparent in full views and prints. Example, one effect popular with photographers is to copy the image into a second layer, set its blending mode to overlay or soft light etc., then apply a blur to it. This somewhat smoothens the image. But it also changes its appearance into a glowy kind of look (which is the aim, usually).   I want a treatment that will fake the appearance of a higher-res smooth image without too many side-effects.  Any tricks of this kind?


I probably read this before 2000 in an anthology work.  I frequently read books like "Best SF of yyyy".  The style of the writing is like that of the SF Golden Age.  Humanity developed interstellar FTL drives and is out exploring the Universe.  The Human ship discovers a inhabitable world with ancient ruins.  The Human ship lands and the crew begin exploring the ruins.  One member of the crew stumbles into an ancient trap that eviscerates and kills him.  It replaces his innards with machine controlled (I don't recall whether it's biological or mechanical) fake.  It also infects at least this crewman and maybe the entire crew with a plague designed to kill the entire Human species.  As the Human ship departs the planet, the machine expresses satisfaction with finally getting revenge on Humanity, the species that eliminated its master's species.  Apparently short-sighted Humanity has completely forgotten the ancient conflict.

Many years ago I read a book or story where a group of people discover a dark city - maybe on another planet - which appears devoid of life but is in very good condition. As they gradually explore the city one of the them falls into a trap and is cut to pieces by something mechanical. This detail I can remember as it was a pretty gruesome idea. I don't know the ending but my guess is that none of them make it out alive.


I'm using  to the specified floating-text-box problem, but there is no way to specify which page the result goes on. I was wondering if there's a way to tell AddToShipoutPictureFG which page to go onto.  So, like the interface, instead of being  \placetextbox{<horizontal pos>}{<vertical pos>}{<stuff>}   would be  \placetextbox{page}{<horizontal pos>}{<vertical pos>}{<stuff>}

I want to arrange pages of my presentation in a rectangular array.  I want to print on each page (what may be the equivalent of) a watermark which is a portion of a glyph.  For this discussion let us say the glyph is a katakana symbol for ka, spread across 6 pages.  When I am done, I should have an array of three rows and two columns of pages with print and with a light-gray water mark on each page, so when I step back some distance, I can look at the watermark(s) and make out the symbol for ka which is about two pages high and two pages wide, but centered so that part of the symbol is on all 6 pages.  I suspect I can use a TeX package for watermarking, but I am asking for an example (or pointer to an example:  I am a TeX beginner) that someone more adept than I can post that I can adapt.   It is my hope that I can for each page issue the same watermark command, using the same scale for the watermark glyph, but using different offsets for each page (which I am willing to input manually).  I am willing to compute the offsets myself to account for the physical space I will use in arranging the pages.  For this example, suppose I will have one inch vertically between sheet edges as well as one inch horizontally.  If there is a better package for this effect, I am willing to use it, but I am hoping the learning curve will be mild.


It's Unity Engine(v2018.1) C#, .Net 3.5 equivalent version.  I got a strange floating point number operation.  The code goes like this.           float   fa = 4.2f;         float   fb = 10.0f;         float   f1 = fa * fb;         int     i1 = (int)(fa * fb);         int     i2 = (int)f1;         int     i3 = (int)42.0f;          Debug.Log(f1);         Debug.Log(i1);         Debug.Log(i2);         Debug.Log(i3);          // Log Result         //         //  f1 : 42         //  i1 : 41         //  i2 : 42         //  i3 : 42         //   i1 is the problem.  Integer type casting gives 41 not 42.  Anybody can give hint about this issue? FP precision or type casting problem?

Consider the following code:   0.1 + 0.2 == 0.3  ->  false   0.1 + 0.2         ->  0.30000000000000004   Why do these inaccuracies happen?


So I am trying to install Ubuntu, I had it before but I removed it because i couldn't re install it, i thought it would work but it didn't. So I cant boot into the install anymore, it says:   SYSLINUX (not sure the number) EDD 4.06-pre7 Copyright (C) 1994-2012 H. Peter Anvin et al  I am trying to boot from a PNY usb flash drive, I know its not the usb because i used this to boot into it brfore also i cant boot into any other linux distro either, so can someone please reply?

I am trying to install linux on my laptop, a Toshiba Satellite C6550-S5200. I did it once but something happened so I removed it then I had to destroy all data on hard drive so now I have nothing on it. Well I got a iso file burned to a CD and to a flash drive. With the flash drive I get.   SYSLINUX 4.06 EDD 4.06-pre7 Copyright (C) 1994-2012 H. Peter Anvin et al  With the CD it will start booting it but somewhere loading it up, the dots turn all orange and stay that way and my CD drive turns quiet.  Oh and some more info the images work because I tried loading them up on another pc and it worked just fine.  I manage to get the CD to boot I just had to let me pc boot up first then insert the CD and have it boot the CD then. Once I get done installing ubuntu it works fine but I have to leave the PC on 24/7 for if I turn it off the PC will freeze 5-10 seconds after booting back up no matter how I install it.


As we already know, the subspace topology is a convenient way to construct topologies from supersets of a set that have a known topology already. Subspace Topology: Suppose you have a set $X$ and a topology on $X$ called $\mathcal{T}_X$. Suppose $Y \subseteq X.$ Then we can find a topology for $Y$, called $\mathcal{T}_Y$, as given by: $\mathcal{T}_Y=\{O \cap Y  \mid O \in \mathcal{T}_X\}$. I'm going to prove that the induced topology only works for $Y \subseteq X$. Namely, I'm going to prove that the subspace topology fails for $Y \not \subseteq X.$ Proof Suppose $X$ is a set and $\mathcal{T}_X$ is a topology on $X$. By way of contradiction, let $Y$ be a set such that $Y \not \subseteq X$ Since $Y \not \subseteq X,$ there is at least one $z \in Y$ such that $z \not \in X.$ Let's attempt to construct a topology $\mathcal{T}_Y = \{Y \cap O \mid O \in \mathcal{T}_X\}$ Then for any $O \in \mathcal{T}_X, O \bigcap X \neq Y$. This is because $z \in Y$ but $z$ will never be in $O$ since $O \subseteq X$ and $z \not \in X.$ Then $Y \not \in \mathcal{T}_Y$ This means that $\mathcal{T}_Y$ is not a topology of $Y$ as it violates the definition of topology Therefore, the subspace topology only works for $Y \subseteq X$ $ \hspace{1cm} \square$

One of the easiest ways to find a topology on a set is to used the Induced Topology. Induced Topology: Suppose you have a set $X$ and a topology on $X$ called $\mathcal{T}_X$. Suppose $Y \subseteq X.$ Then we can find a topology for $Y$ (call it $\mathcal{T}_Y$) as given by: $\mathcal{T}_Y=\{O \cap Y  \mid O \in \mathcal{T}_X\}$. My question is: does the induced topology still hold for sets $Y \not \subseteq X.$ Suppose $Y \cap X = \emptyset.$ Can we still inherit a topology on $Y$ if $X$ and $Y$ are disjoint? I'm going to say no. Here's my test: Let $X =\{1,2\}$ and $\mathcal{T}_X = \{\emptyset,\{1\},\{1,2\}\}$ Let $Y = \{5\}$ Then, following from our induced topology method, $\mathcal{T}_Y=\{\{5\} \cap \emptyset, \{5\} \cap \{1\}, \{5\} \cap \{1,2\}\} = \{\emptyset,\emptyset,\emptyset\}$ But this fails to satisfy definition of topology since $Y=\{5\}$ and $Y \not \in \mathcal{T}_Y.$ So it would seem that we need $Y \subseteq X$ so that $Y \in \mathcal{T}_Y$, otherwise we end up with a bunch of empty sets. Is my reasoning here correct?


For the past couple days, following an attempt to update the OS, my computer shows this on boot-up:    The only reason I'm using it right now is that I booted up from an older version, but I've had problems with installing new version before, and also getting error messages like this:    I believe I've also had problems removing old ones through the terminal.  Anyways, what's the best route at this point?   EDIT:  Understanding it as a kernel panic, I managed to get some info on my boot files. Here's what came up.    => Grub2 (v1.99) is installed in the MBR of /dev/sda and looks at sector 1 of      the same hard drive for core.img. core.img is at this location and looks      in partition 112 for .  sda1: __________________________________________________________________________  File system:       ext2 Boot sector type:  - Boot sector info:  Operating System:   Boot files:        /grub/grub.cfg   sda2: __________________________________________________________________________  File system:       Extended Partition Boot sector type:  Unknown Boot sector info:    sda5: __________________________________________________________________________  File system:       crypto_LUKS Boot sector type:  Unknown Boot sector info:    ubuntu-vg-root': _______________________________________________________________  File system:        Boot sector type:  Unknown Boot sector info:  Mounting failed:   mount: unknown filesystem type ''   ubuntu-vg-swap_1': _____________________________________________________________  File system:        Boot sector type:  Unknown Boot sector info:  Mounting failed:   mount: unknown filesystem type ''   mount: unknown filesystem type ''  ============================ Drive/Partition Info: =============================  Drive: sda _____________________________________________________________________  Disk /dev/sda: 1000.2 GB, 1000204886016 bytes 255 heads, 63 sectors/track, 121601 cylinders, total 1953525168 sectors Units = sectors of 1 * 512 = 512 bytes Sector size (logical/physical): 512 bytes / 512 bytes  Partition  Boot  Start Sector    End Sector  # of Sectors  Id System  /dev/sda1    *          2,048       499,711       497,664  83 Linux /dev/sda2             501,758 1,953,523,711 1,953,021,954   5 Extended /dev/sda5             501,760 1,953,523,711 1,953,021,952  83 Linux   "blkid" output: ________________________________________________________________  Device           UUID                                   TYPE       LABEL  /dev/mapper/sda5_crypt mLMv6i-emLW-vtk7-IRqk-QNrh-WhXk-VLqRFf LVM2_member  /dev/mapper/ubuntu--vg-root 5077026c-b631-4601-b0e9-fc228c6860e9   ext4        /dev/sda1        8fb7c16b-f131-4622-86f0-e3a54e5272c3   ext2        /dev/sda5        37bfa81a-5253-4b9e-bfb3-963476e52b17   crypto_LUKS   ========================= "ls -R /dev/mapper/" output: =========================  /dev/mapper: control sda5_crypt ubuntu--vg-root ubuntu--vg-swap_1  ================================ Mount points: =================================  Device           Mount_Point              Type       Options  /dev/mapper/ubuntu--vg-root /                        ext4       (rw,errors=remount-ro) /dev/sda1        /boot                    ext2       (rw)   ============================= sda1/grub/grub.cfg: ==============================     Specs:   Memory: 3.9 GiB Processor: Intel® Core™2 Quad CPU Q8300 @ 2.50GHz × 4  Graphics: Gallium 0.4 on NV96 OS: 64-bit Disk: 980.1 GB (and yet it says I don't have enough space in boot)

My /boot partition is nearly full and I get a warning every time I reboot my system. I already deleted old kernel packages (linux-headers...), actually I did that to install a newer kernel version that came with the automatic updates.  After installing that new version, the partition is nearly full again. So what else can I delete? Are there some other files associated to the old kernel images?  Here is a list of files that are on my /boot partition:  :~$ ls /boot/ abi-2.6.31-21-generic         lost+found abi-2.6.32-25-generic         memtest86+.bin abi-2.6.38-10-generic         memtest86+_multiboot.bin abi-2.6.38-11-generic         System.map-2.6.31-21-generic abi-2.6.38-12-generic         System.map-2.6.32-25-generic abi-2.6.38-8-generic          System.map-2.6.38-10-generic abi-3.0.0-12-generic          System.map-2.6.38-11-generic abi-3.0.0-13-generic          System.map-2.6.38-12-generic abi-3.0.0-14-generic          System.map-2.6.38-8-generic boot                          System.map-3.0.0-12-generic config-2.6.31-21-generic      System.map-3.0.0-13-generic config-2.6.32-25-generic      System.map-3.0.0-14-generic config-2.6.38-10-generic      vmcoreinfo-2.6.31-21-generic config-2.6.38-11-generic      vmcoreinfo-2.6.32-25-generic config-2.6.38-12-generic      vmcoreinfo-2.6.38-10-generic config-2.6.38-8-generic       vmcoreinfo-2.6.38-11-generic config-3.0.0-12-generic       vmcoreinfo-2.6.38-12-generic config-3.0.0-13-generic       vmcoreinfo-2.6.38-8-generic config-3.0.0-14-generic       vmcoreinfo-3.0.0-12-generic extlinux                      vmcoreinfo-3.0.0-13-generic grub                          vmcoreinfo-3.0.0-14-generic initrd.img-2.6.31-21-generic  vmlinuz-2.6.31-21-generic initrd.img-2.6.32-25-generic  vmlinuz-2.6.32-25-generic initrd.img-2.6.38-10-generic  vmlinuz-2.6.38-10-generic initrd.img-2.6.38-11-generic  vmlinuz-2.6.38-11-generic initrd.img-2.6.38-12-generic  vmlinuz-2.6.38-12-generic initrd.img-2.6.38-8-generic   vmlinuz-2.6.38-8-generic initrd.img-3.0.0-12-generic   vmlinuz-3.0.0-12-generic initrd.img-3.0.0-13-generic   vmlinuz-3.0.0-13-generic initrd.img-3.0.0-14-generic   vmlinuz-3.0.0-14-generic   Currently, I'm using the 3.0.0-14-generic kernel.


So I was wondering if I will get back my IAPs after reinstalling an app from the Google Play Store. It's because I have an app where I've made a lot of IAPs and I've uninstalled it due to insufficient storage.  Any help would be appreciated.

I'm trying the free version of an app, and I'm considering to upgrade to the Premium version. The said app is .  From what I see, the Premium version in not directly available on Play Store, and it can be purchased only in-app.  How do these purchases work? If I  uninstall the app then reinstall it later, or if in the future I change my phone, this purchase will still be recognised?  Will I be able to use the full version again without having to pay once more for it?   It appears that the purchase is managed by Google Play:


please help me to solve this error.i tired from searching solution... error: SQLSTATE[42000]: Syntax error or access violation: 1064 You have an error in your SQL syntax; check the manual that corresponds to your MariaDB server version for the right syntax to use near 'WHERE name=NULL' at line 1  my database have 3 column=id(int),name(varchar),comment(varchar) and i want insert comment to it.  my php code :  <?php include "./Config.php"; include './MyPDO.php';    $response = array() ;   $connect = MyPDO::getInstance();    $name = $_REQUEST['name'];   $comment=$_REQUEST['comment'];          $query =  " INSERT INTO user "                 . " (comment) "                 . " VALUES "                 . " (:comment) "                 . " WHERE name=:name ";          $stmt = $connect->prepare($query);         $stmt->bindParam(":name",$name);         $stmt->bindParam(":comment",$comment);         try {                 $stmt->execute();                 $response['massage'] = "sucess";                 echo json_encode($response);                 exit;         } catch (PDOException $ex) {                  $response['massage'] = "error";                 $response['error']=$ex->getMessage();                 echo json_encode($response);         }

What's wrong with this query: INSERT INTO Users( weight, desiredWeight ) VALUES ( 160, 145 ) WHERE id = 1;  It works without the WHERE clause. I've seemed to have forgot my SQL.