I recently installed ubuntu 14.04 on my home PC. Installation proceeded with no problems at all, but now I'm having trouble with the video drivers. The drive I need to install is SiS 671, v.7.14.10.5280, A01, I have the zip file downloaded, but is for windows.   When I go to configurations the drive used is a generic one, and no other option for choice.  I really need to install this driver, cause my screen isn't working very well with the generic one.  Clarification of the question: How to install SiS 671, v.7.14.10.5280, A01 driver on ubuntu 14.04?

I am buing assamble self PC for playing games.  I am wondering, all the drivers, which are most likely for Windows, can i just use them on Ubuntu?  So if i understand you right, it will automaticaly detect the drivers, no need for installs ? or it find custom drivers for ubuntu.  This is the setup, will there be any problem with it?


I've got an optimization problem with these properties:   The goal function is not cheap to compute. It can be evaluated up to around 10^4 times in the optimization. There's a lot of local optima. High values are clustered around the maximum, so the problem is kind of convex. The solutions are constrained to a known hyperbox. The gradient is unknown, but intuitively, the function is smooth. It's a function of up to 50 variables. The graphs below are examples of the 2D special case.   Nelder-Mead gets stuck in the local optima a lot. Above three variables, there's no chance of using brute force. I've looked into genetic algorithms, but they seem to require a lot of evaluations of the goal function.  What kind of algorithm should I be looking for?

Gradient descent and many other methods are useful for finding local minima in cost functions. They can be efficient when the cost function can be evaluated quickly at each point, whether numerically or analytically.    I have what appears to me to be an unusual situation. Each evaluation of my cost function is expensive. I am attempting to find a set of parameters that minimize a 3D surface against ground truth surfaces. Whenever I change a parameter, I need to run the algorithm against the entire sample cohort to measure its effect.  In order to calculate a gradient, I need to change all 15 parameters independently, meaning I have to regenerate all the surfaces and compare against the sample cohort way too many times per gradient, and definitely way too many times over the course of optimization.  I have developed a method to circumvent this problem and am currently evaluating it, but I am surprised that I have not found much in the literature regarding expensive cost function evaluations.  This makes me wonder if I am making the problem harder than it is and that there might be a better way already available.  So my questions are basically this: Does anyone know of methods for optimizing cost functions, convex or not, when evaluation is slow?  Or, am I doing something silly in the first place by rerunning the algorithm and comparing against the sample cohort so many times?


I'm having a pretty big issue that I need to get resolved. Basically I have little experience using Linux and I've been working on a project recentley that involves me having to use quite a lot of Linux commands to run php scripts on my web server.  Basically I've two scripts   get_tweets.php parse_tweets.php   I need these to be running constantly for the next 3 - 4 weeks on my web server. I use the following command to get them to run and they seem to last for the day but when I check in the morning they seem to have stopped working!  nohup php get_tweets.php > /dev/null & and then nohup php parse_tweets.php > /dev/null &   I know that by using & I can keep the scripts running in the background and they run when I log out of ssh but like I said they seem to run fine all day then when I check in the morning they've stopped.   The issue I am having is how I can keep them running non stop. Is there a simple script I could write to check if they are running and if not then restart them or perhaps restart them every 5 hours or something?  I'd appreciate any help guys as this is quite a big issue and I've got no idea how to resolve it.

I am very new to Linux and I've only been using it to SSH to my web server using Putty. The issue I am having is this:  Basically I've got 2 php scripts. One get_tweets.php constantly listens for tweets on twitters Streaming API whilst the other - parse_tweets.php logs these into a db. In order for these to work they've to be kept running continuously.   I've been using the following commands to run them in the background and from what I've seen they run for most of the day, however whenever I log on to my computer in the morning the scripts have stopped and I've to run commands again.  nohup php my_script.php > /dev/null &   I'm just wondering if that is normal based on the commands I am using, should they run indefinitely when using nohup and if not what is the alternative? A CRON job?  Thanks for the help


When you have that you basically have: \begin{align*} \sqrt{x^2} & < \sqrt{1} \iff\\ |x| & < \pm 1 \end{align*} Doesn't that give you 2 options? $|x| < 1, |x| <-1$? The latter is false because $|x|$ is always positive right?  So to solve this $-1 < x < 1$. Correct?

How $\sqrt{x}$ can be a function when $\sqrt{4}$ is equal to $-2$ and $2$?


I have installed a fresh version of Windows 10 while the boot mode was legacy mode in the BIOS. When I change it to UEFI Windows does not boot anymore.   How can I use UEFI mode?

I've installed Windows 10 in BIOS mode and use MBR. How can I convert it to use UEFI and GPT without reinstalling Windows 10? Is this possible?


I don not see any reason why the close tag "/" at the end of  never works when you need to import a JavaScript. I had to go through a thousand line code just to find that this was the bug. Shouldnt HTML automatically parse the end of tag closes?

What is the reason browsers do not correctly recognize:  <script src="foobar.js" /> <!-- self-closing script element -->   Only this is recognized:  <script src="foobar.js"></script>   Does this break the concept of XHTML support?  Note: This statement is correct at least for all IE (6-8 beta 2).


I got a query containing this:  INNER JOIN  com ON com.company_id = pi.company_id AND com.company_name LIKE '%TUTTO PER L'UFFICIO%'   coldfusion show this error:      Incorrect syntax near 'UFFICIO'   How can I fix this?  P.S. can't use cfparam because this is not in a query(is in <cfsavecontent variable = "sql_query"> ... </cfsavecontent>)

I am coding in ColdFusion, but trying to stay in cfscript, so I have a function that allows me to pass in a query to run it with   <cfquery blah >   #query# </cfquery>   Somehow though, when I construct my queries with sql = "SELECT * FROM a WHERE b='#c#'"  and pass it in, ColdFusion has replaced the single quotes with 2 single quotes.  so it becomes  WHERE b=''c'' in the final query.  I have tried creating the strings a lot of different ways, but I cannot get it to leave just one quote.  Even doing a string replace has no effect.   Any idea why this is happening?  It is ruining my hopes of living in cfscript for the duration of this project


I would like a quick way to move between parts of a word e.g.:  this_is_a_variable_name ^    ^  ^ ^        ^  thisIsAFunctionName ^   ^ ^^       ^     This would increase the speed in certain situations when only part of the word needs to be modified / deleted e.g.:  +--------+----------------------+------------------+---------------------+ | change | k_error_write_stream | sendAckMessage   | printMessageAndExit | | to     | k_error_read_stream  | sendReplyMessage | printMessage        | +--------+----------------------+------------------+---------------------+

Often I'll be doing a quick edit to a camel case word in some code and wish I could use something like text-objects to select one part of the camel case word.  For example, given this snippet:  class TextObject:     pass   If my cursor is on the 'x' in TextObject, I would like to quickly select/operate on the word 'Text'.  If my cursor is on the 'j', I would like to manipulate the word 'Object'.    Vim text-objects allow me to quickly manipulate the entire word TextObject (e.g 'caw'), but I've noticed that I quite often want to manipulate only a single word in a camel case string like this.  Any pointers?  Thanks in advance


I was studying the BOTW grass shader and noticed how the . From watching gameplay it appears the . I can't find any way to do something like this in unity and am wondering if anybody has advice, or can guess as to how they did it. Thanks!

. I tried to imitate the LOD effect in unity using crossfade LOD but . I've done some research into the subject but can't seem to find anything about blending foliage in this way so I'm looking for advice. Thanks so much!


I need to prove sum of series: $$\sin \theta+\sin 2 \theta+\sin 3\theta+\dots=\sum_{n=1}^\infty \sin n\theta$$  by using in the first place the complex numbers.

Prove that if $\phi$ is not equal to $2k\pi$ for any integer $k$, then  $$\sum_{t=0}^{n} \sin{(\theta + t \phi)}=\frac{\sin({\frac{(n+1)\phi}2})\sin{(\theta+\frac{n \phi}2)}}{\sin{(\frac{\phi}2)}}$$  Find a similar formula for  $$\sum_{t=0}^{n}\cos{(\theta+t\phi)}$$  where the functions sin and cos appear on the right-hand side.  Find, for all $\theta$, the values of   $$\sum_{t=0}^{n}\cos^{2}{(2t\theta)}$$ and $$\sum_{t=0}^{n}\sin^{2}{(2t\theta)}$$


I have the following code.  I cannot for the life of me find a way to lay the table under the pink figure ..    \documentclass{article}  \usepackage[english]{babel} \usepackage{tikz} \usetikzlibrary{arrows,automata} \usepackage{adjustbox}  \begin{document}  \begin{adjustbox}{center} \begin{tikzpicture}[->, >=stealth', shorten >= 2pt, auto, node distance=8cm, thick] \tikzstyle{every edge}=[draw=black,thick] \tikzstyle{every state}=[fill=white, draw=black, thick, text=black, scale=1] \node[state] (1) {\tikz \draw[->,very thick] (0,1) -- (1,0);}; \path (1) edge [loop left] node[left] { \fbox{\scalebox{.5}{\tikz \filldraw[draw=red,fill=red!20] rectangle (3,3);}} \\ \\ \begin{tabular}[b]{ll} p: 78\%&\\[2ex] $\mu$: -7\% & $\sigma$: 7\%\\ $\alpha$: 0.38 & N: 11977 \end{tabular} } (1); \end{tikzpicture}\end{adjustbox}  \end{document}   any help? thx ! :-)

How can I insert a line break in a TikZ node? Simply putting \\ where I want the break doesn't work (see MWE).  Is there a way to make lines break automatically at some specified width?  And can I control the alignment of the text (left, right, centered, justified)?  \documentclass{article} \usepackage{tikz} \begin{document} \begin{tikzpicture} \node {First line\\second line}; \end{tikzpicture} \end{document}


I know how to do a heat distortion effect in compositing.   What I am looking for is a way to do the same effect with a material set up in cycles.   What would be the best way to create a procedural material that can be placed in front of any object and make it look like heat is rising in front of it (without compositing)?  Any ideas would be greatly appreciated.

How can I make a  effect, like you might see around the exhaust of a jet engine?


What causes an f/0 error on a Nikon D700? ... I'm having a problem with my lens (Sigma 24-70mm.2.4 )i get a black frame randomly. Ive tried updating my firmware without results

Recently (and always at the worst possible time) my camera will either freeze and give me an f/0 error code or will shoot with a strange click that sounds like the shutter is getting stuck. The resulting image is always black.   My gut instinct suspects there is either a communication problem between the lens (Nikkor 24-70 ED) and the camera or the aperture diaphragm is in the process of failing.


In ubuntu bash script how to remove space from one variable  string will be      3918912k    Want to remove all blank space.

I have a shell script with this code:  var=`hg st -R "$path"` if [ -n "$var" ]; then     echo $var fi   But the conditional code always executes, because hg st always prints at least one newline character.   Is there a simple way to strip whitespace from $var (like trim() in )?   or   Is there a standard way of dealing with this issue?   I could use  or , but I'd like to think there is a more elegant solution to this problem.


class Test{     public static void main(String[] arg){         String str1="a,,";         String str2="a,,b";         System.out.println(str1+" len="+str1.split(",").length);         System.out.println(str2+" len="+str2.split(",").length);     } }   The output is  a,, len=1 a,,b len=3   Isn't the number of parts supposed to be 3 in both the cases?

Check out the below program.   try {     for (String data : Files.readAllLines(Paths.get("D:/sample.txt"))){         String[] de = data.split(";");         System.out.println("Length = " + de.length);     } } catch (IOException e) {     e.printStackTrace(); }   Sample.txt:   1;2;3;4 A;B;; a;b;c;   Output:   Length = 4 Length = 2 Length = 3   Why second and third output is giving 2 and 3 instead of 4. In sample.txt file, condition  for 2nd and 3rd line is should give newline(\n or enter) immediately after giving delimiter for the third field. Can anyone help me how to get length as 4 for 2nd and 3rd line without changing the condition of the sample.txt file and how to print the values of de[2] (throws  ArrayIndexOutOfBoundsException)?


According with what was sayed on another question:     The spread operator is like Object.assign and does not deeply clone an   object. The reason the JSON thing worked is because you created a   whole new object which would pass the strict equality check, however   all your components would update needlessly because nothing will pass   a strict equality check now.      Object.assign({}, ...prevState, ...newState) would create a new   top-level object, but it would not create a new object for any objects   nested in prevState or newState. However, you would have to carefully   update nested objects so as to avoid needless re-renders. This can get   tricky for deeply nested objects and arrays.   My question is.... what must we do when we need to return a new version of an object that have properties tha contains arrays? For example:  const foo = {   myArray: [1, 2, 3],   name: 'Hello world' };  const clonedObj = { ...foo }   This will create a new object with a copy of name and it's content, a copy of myArray key BUT not with a copy of [1, 2, 3].  JSON.parse + JSON.stringify does the trick but don't look like a clean way.  What alternative do I have?  Thank you

What is the most efficient way to clone a JavaScript object? I've seen obj = eval(uneval(o)); being used, but . I've done things like obj = JSON.parse(JSON.stringify(o)); but question the efficiency.  I've also seen recursive copying functions with various flaws.  I'm surprised no canonical solution exists.


How do you enable USB Debugging on a bootloop-ed device?  Or, at least, how do you determine if a bootloop-ed device has the USB Debugging option turned on?

I successfully flashed a stock ROM on my Galaxy Note 4 using Odin 3.13.1 but, unfortunatelly, the bootloop is not gone.  Device info:    SM-N910C unrooted Android 6.0.1 Marshmallow   Bootloop sequence: Samsung boot screen —> Android is starting... Optimising Apps 2 of 2. —> Android is starting... Starting apps. —> LOOP  What are my options to restore my personal data from now on?


As per Ptolemy, he proposed firstly geocentric model and that model if one see with aspects of relativity he would find true. Here is an example how  Suppose you are in a train which is moving and you are sitting in train. A man at platform is waving you and he is steady at his position. Then you would probably see man going backwards if train is moving forwards.  Question arises from this in one's mind that how absolute motion can be observed in a moving frame.  If you apply this logic to Ptolemy model, You would probably conclude that neither earth is perfectly centre nor sun and earth is stationary(relative to sun) and sun is moving. Then if you are on earth which is itself moving, let's assume heliocentric is true which everyone believes even me, then how we can conclude somehow that sun must be stationary(relative to earth). If someone here argues even me that we have gone to outer space and viewed sun is stationary and earth is moving along it, but here comes another possibility too that maybe the end of our galaxy is moving so again similar thing happen that how absolute motion can be detect from a moving frame. So to have some proper results between heliocentric and geocentric some proper research must be done to solve such questions.  If any of you have some answers please write, I will be pleased if you do so.

Trying to observe the night sky for a few weeks, the motion of the Sun and the stars pretty much fits into the Geocentric Theory i.e. All of them move around the Earth.  What then, which particular observation, made us think that it could be the other way around, that all the planets move around the Sun?


After creating a post in SE Android app, I can't open it for some time as it says "Failed to load question". This started happening suddenly, a week ago. Now I have to use the website. (It loads the question In the website).  I am using SE app on Android 5.0

I recently posted a new question on Android Enthusiasts using the official StackExchange app for Android. Right after posting the question, the app said that my question is not available.     The question is not available, it may have been deleted.   Deleted? Already?...  Then I navigated to my user name to see my recent activity. There it was! I could see the question I just posted. But if I tapped on the link to try to open it, the app kept complaining about my question not being available.     The question is not available, it may have been deleted.   But 7 minutes after posting the question, I could see my question. Here are some screenshots that showcase this issue.      This is not the first time this happens. This appears to be more or less normal behavior of the app. I don't use the StackExchange app very often to post questions. But I had exactly the same message come up when I posted a question a few months ago (and some app version numbers earlier).  This is not a major issue, but you should try to address this nevertheless. It's a small bug, but addressing it might imply much bigger changes... which might explain why it's still present... I don't really know, I'm guessing. I just thought I would let you know about it, in case you are not aware of it.  For the record, the phone is Galaxy S4 Plus (GT-I9506) running Android 4.4.2. Version number of the app is 1.0.50.


For the below code:  String bis = "good"; String cis  ="good"; char[] ch = {'g','o','o','d'}; String temp=""; for (char c:ch){     temp=temp+c;         } System.out.println(temp);  System.out.println(cis==bis); //true System.out.println(bis==temp); //false   'temp' variable evaluates to "good" same as 'bis' and 'cis' but bis==temp returns false unlike bis==cis which evaluates to true.Please let me know why this happens? In String pool "good" object is there.So 'temp' reference should ideally be pointing to it right as done by bis and cis?

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


I have a website mywebsite1.com runing wordpress and hosted on digitalOcean droplet using LEMP (Nginx/php/mysql) on Ubunto server, am trying to duplicate the same site and use a new DNS mywebsite2.com to point to the new droplet IP, the problem is that the new DNS doesn't load and try to connect to the server then stop loading, here what I got on fireFox :  Unable to connect   on chrome :  This webpage is not available ERR_CONNECTION_REFUSED   I am a Linux beginner, so for sure there's something missing .. here what I did step by step :   On my DNS provider I added A type mywebsite2.com to point to my new Droplet IP. CNAME www.mywebsite2.com to point to  mywebsite2.com Updated my databasedump.sql with the new domain mywebsite2.com Updated my config.php file (Wordpress) Renamed my website directory :      /home/html/mywebsite1.com to /home/html/mywebsite2.com   ls -l       Go to :      /etc/nginx/sites-available and renamed mywebsite1.com to mywebsite2.com and updated all the file    Delete the old symlink and create a new one for the new DNS, using this cmd :      sudo ln -s /etc/nginx/sites-available/mywebsite2.com   /etc/nginx/sites-enabled/mywebsite2.com    Restart nginx ..   Note : I have an SSL certificate (Wildcard) that is working on mywebsite1.com, but recently bought a new one for mywebsite2.com and left the same config and put the new certification files (public & private)  Note 2 : Runing ping to mywebsite2.com is working and whois (cmd) give me the right DNS provider.  What am I missing please? Any suggestion is very welcome am trying to figure out what is wrong.  Thanks!

This is a  about Connection Refused    We see a lot of questions to the effect      When I try to connect to a system I get a message      Connection refused      Why is this ?


So as you can see there is some very weird lighting on the body of my model. My initial thought was that it was the normals, however after recalcualting and checking manually that they were facing the correct direction, still nothing changed.  Thoughts? Also, sorry if it's an obvious answer, i'm new to blender

I'm currently working on a model of an X-wing that I'm intending for use in a game and running into a bit of trouble with the shading of the mesh. The upper nose is rounded off where the sensor cone attaches, but at the point it reaches the canopy frame it flattens out and meets at a corner.  Everything is fine and dandy when the sides are modeled:    but once I close it off and add the top of the nose, the shading goes to hell:    As you can see, the smoothing gets confused at the lip of the cockpit.  I've tried a couple different means of getting around this, none of which looks right while maintaining the correct shape. The transition from the rounded to flat is a fairly important part of the ship's character, so I don't want to discard the contours, either.  Any tips or suggestions on modeling this area?  Addendum:  If I eliminate that second angle where the canopy frame meets the fuselage as marked in red:    this also fixes the smoothing. However this is not a solution, as the angle is a part of the design. It DOES give me another thought on fixing, but I won't be able to test it until I get home.


After I receivd a notification that someone answer my question, opened app from the notification and app crashed. Unfortunately, it crashes every time I try to open. The app is totally unusable now. Please fix.   iphone 6, os 9.1

Upon clicking on SE icon, blue (starting) screen appears and then I am back to home screen, SE app simply won't start. This kind of behaviour never happened before (on any other app). I tried to remove it from "task manager", reinstalling and logging back in; neither did work. In Settings -> Stack Exchange -> Notices I found a log message:  FILE DOESN'T EXIST, WILL CREATE: users/dev/buildagent/work/{id}/pods/target support files/pods/pods-ack...plist   App Version: 1.4.0 Device: iPhone7,2 OS Version: Version 9.1 (Build 13B143)   TLDR: app starts when cellphone has no internet access. I just noticed when I am on 3G (cellular internet) it crashes ASAP, but when I am on wifi that has no internet (for LAN etc.) app starts normally but no new content, when I turn off WiFi and iPhone switches to cellular; app crashes. Note: I turn off WiFi using control center - so I never leave the app. Another thing, when I force iPhone to use EDGE (slowest possible internet) app starts, and crashes after 5 seconds or so. I assume when app downloads some data from server.  Known workaround (works for me too)  I found a workaround: turn on Airplane Mode, launch the app, then turn Airplane Mode off. – NobodyNada


Is there a way to use Google Web font with Sublime-Text 3 without admin privileges on Windows? I tried  but couldn't get it to work.  I can't install the fonts locally as I do not have admin privileges.

I know you can put custom fonts in say C:\Windows\Fonts and applications will be able to find and use them. However this is only possible when you have administrator access to the machine, which is rarely the case in shared environments.  Is there a general way to use custom fonts from some other location suitable for non-admin users? If not, is there any manner specific for Adobe Fireworks (CS3) and Office 2007?  I'm interested mainly in XP and Vista, but a solution that works for other Windows versions would be great.


I am trying to implement a wrapper library for an Arduino-based ESP8266 which will act as a Modbus controller.   The Modbus library I am using (ModbusMaster) has a function which sets what is to be done before each transmission: _modbus.preTransmission(void( *preTransmission)().   I am trying to figure out how to set my function MyWrapperClass::preTransmission() to be the callback function.  MyWrapperFunction::MyWrapperFunction() {     _modbus.begin(_slaveId, serial); //_modbus defined in header file ModbusMaster _modbus;    _modbus.preTransmission(this->preTransmission);   _modbus.postTransmission(this->postTransmission); }  void MyWrapperFunction::preTransmission() {   //Stuff before transmission }  void MyWrapperFunction::postTransmission() {   //Stuff after transmission }   But I get various compiler errors (depending on what I'm doing), including:  error: no matching function for call to 'ModbusMaster::postTransmission(<unresolved overloaded function type>)'   Also sorry if this is a duplicate - it is very hard to search for similar things when you don't know the terms to search for. I am sure that this has been asked before but I couldn't find an answer.

I'm using an API that requires me to pass a function pointer as a callback. I'm trying to use this API from my class but I'm getting compilation errors.   Here is what I did from my constructor:  m_cRedundencyManager->Init(this->RedundencyManagerCallBack);   This doesn't compile - I get the following error:      Error  8 error C3867: 'CLoggersInfra::RedundencyManagerCallBack': function call missing argument list; use '&CLoggersInfra::RedundencyManagerCallBack' to create a pointer to member   I tried the suggestion to use &CLoggersInfra::RedundencyManagerCallBack - didn't work for me.   Any suggestions/explanation for this??  I'm using VS2008.  Thanks!!


I have a Micro-SD card which I keep permanently inserted in my MacBook Pro using a nifty Mini-drive. I doubt it should matter, but this is a , running High Sierra (hardware doesn't support upgrading to Mojave, and app store actively prevents it).  Since I use this as my long-term "tepid" storage (not disconnected "cold" storage, but not using space on my more actively used SSDs), I would prefer that it be mounted in a manner where it cannot be ejected from the OS, either through Finder, or  or any other means.  Is there a way of flagging the device, through Disk Utility, fstab or some other manner, to do so? Essentially, for it to behave like a permanent/fixed disk, as opposed to it being removable?

I have a Mac Mini with a few external drives connected that I use as a home server. Normally the Eject buttons next to the drive icon are really handy as they let me eject an external drive very easily (compared to Windows for instance).  However on a Mac server, this comes as a detriment. I have some pretty mission critical stuff on external drives and there's a lot of scripts etc. I have set up that are dependent on those drives being there. Being able to so easily accidentally eject those drives makes me rather uneasy.  So far I've just chosen to not show them in the Finder sidebar, that way at least they're a bit harder to eject. However that isn't very ideal because: (1) I need to go to my Mac in the sidebar to access the drives rather than have the drives accessible directly and (2) the eject buttons still show in open/save dialogue boxes for those drives.  Ideally, I'd like a way for them to behave the way internal drives do: no option to easily eject from the finder, but still possible to unmount through disk utility.


I am trying to find an irreducible polynomial of degree 3 in Z5 and then use that polynomial to construct a finite field. I found that the polynomial $x^3 + x^2 + 1$ is irreducible in Z5 (since none of 0, 1, 2, 3,4 are roots). But I'm stuck on how to use that polynomial to construct a finite field.

I want to construct a field with $125$ elements. My idea is to consider the polynomial ring $\Bbb F_5[x]$. It is enough to find an irreducible polynomial $f\in \Bbb F_5[x]$ of degree $3$ because then $\Bbb F_5[x]/(f)$ is a field with exactly $5^3=125$ elements.  How do I find an irreducible polynomial of degree $3$ in $\Bbb F_5[x]$?


We want to prove that the quadratic fields have form $\Bbb Q(\sqrt d) $, where $d\neq 0,1$  is a square free integer.  Proof. Let $F$ be a quadratic field. So we have $F=\Bbb Q(\alpha)$, for some $\alpha \in \Bbb C$. So, the degree of the minimal polynomial of $\alpha \in \Bbb C$ is $\deg f_\alpha = 2$. So, this polynomial has the form $$f_\alpha(X) =X^2+pX+q,$$ where $p, q\in \Bbb Q$. So, since $\alpha $ is a root, it must be $$\alpha=-p/2\pm \sqrt D, $$ where $D = p^2 /4-q \in \Bbb Q$. Clearly $D $ is not $0$. Then, $$F= \Bbb Q(\alpha) =\Bbb Q(-p/2 \pm \sqrt D) =\Bbb Q(\sqrt D). $$  Since $D\in \Bbb Q$, $D=a/b$, for some integers $a,b $ with $b≠0$. So, $b^2D=ab$.  In this point, in my notes it is written *"collecting all squares in $ab$ together, we can write $ab = c^ 2d$, with $c, d \in \Bbb Z \backslash \{0\}$ and d squarefree." *  I can not understand this step. It might be an easy one, but frankly I can't see it. Could you please elaborate?

I'm having some difficulties continuing this problem. I get that $b^2\mid a$ and $c\mid a$ but I am not sure where to go from there.


According to Google Search, "if it wasn't for you <verb>ing" and "if it weren't for you <verb>ing" are both used.   What is the correct usage of wasn't or weren't in this case?

From my research online the correct way is to say "If I were you" and not "If I was you" because this is the "subjunctive mood".  However they don't say the underlying reason for it. They just say use "If I were you" when it is subjunctive.  What if I wanted to say "If he was you", should I use "if he were you" instead? Since most post talk about "If I.." I have no way to know what would be the correct way for "If he...", "If she..", etc.  I read that the subjunctive is a mood and not a Tense. With Tenses you know the conjugation. How does it work with the moods?  I found  which has a long list of conjugations, and it has "I were" for the Past subjunctive.   So, when I am saying "If I were you":   Am I using the "Past Subjunctive"?  And therefore I should also say "If he were you"?


On some of our servers /var/log, which is a separate ext4 partition, shows that 100% of the 4.8G of space is in use. But it actually occupies around 200M of disk space. Application can still write logs to the directory. What could be the cause of this bug?  Other information: Debian version: 9.9 Inodes use 1%

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


I have been developing a MySQL database that makes some use of BLObs. This has now been transferred on to a virtual machine (VM) in preparation for going fully into the 'cloud'. However some of the larger and more complex queries have caused MySQL to drop out!  These were not a problem on my laptop. Investigating this it seems to occur when RAM usage in approaching max and Swap is maxing out. Looking at the configuration my humble laptop has twice as much RAM and fives times more Swap. The perceived wisdom seems to be that for servers the ratio of Swap to RAM is lower than for PCs. The question is how do I go about calculatng the RAM/Swap requirements?  Thank you...

What rules should I follow to determine how much swap space my linux-based computer should have today?


in Euclid for infinite primes we define $p_0= 2, p_n = p_0p_1...p_{n-1}+1$ that way we get a series so that for every $n \in \mathbb{N}$ we get that $p_n$ is divided by a prime not one of $ p_0,...,p_{n-1} $.   my question is: does for every $n \in \mathbb{N}$ we get that  $ p_n $  is a prime itself ?    i will be grateful if someone will give me a counterexample or a proof for this statement.

I've expressed Euclid's proof on the infinitude of primes on Mathematica:  f[x_] := Product[Prime[n], {n, 1, x}] + 1 TableForm[Table[{f[x], PrimeQ[f[x]]}, {x, 1, 20}]]   Which results in:  $\begin{array}{ll}  3 & \text{True} \\  7 & \text{True} \\  31 & \text{True} \\  211 & \text{True} \\  2311 & \text{True} \\  30031 & \text{False} \\  510511 & \text{False} \\  9699691 & \text{False} \\  223092871 & \text{False} \\  6469693231 & \text{False} \\  200560490131 & \text{True} \\  7420738134811 & \text{False} \\  304250263527211 & \text{False} \\  13082761331670031 & \text{False} \\  614889782588491411 & \text{False} \\  32589158477190044731 & \text{False} \\  1922760350154212639071 & \text{False} \\  117288381359406970983271 & \text{False} \\  7858321551080267055879091 & \text{False} \\  557940830126698960967415391 & \text{False} \\ \end{array}$  The proof flaws for all those values, how is it considered a proof then? I guess that there might be infinite prime numbers according to the proof, but what is the guarantee that at some point it won't fail indefinitely?


I would like to add a menu link using the "Link"-Field with Autocomplete, but I would like to add a parameter afterwards.  Pretty much like this:    ...which is not working.  Is that possible? Thanks!

I'm pretty new to Drupal 8.  I'm trying to figure out how to programmatically add a query string to a menu item link, the specific query string is determined by the node/page the user is currently on.  For example, I've got a link on my primary menu that goes to   If I'm on the 'about me' page I want the link to add a query string of '?origin=about'. ()  If I'm on the 'contact me' page I want the link to add '?origin=contact', etc.  Are there any modules where this can be done, or how might I go about doing this myself?


*Well I have created a basic servlet program Where if user give their USN number correct it will fetch data from database else it will redirect to error.html Whenever I Enter USN number it shows NullPointerException .Since I am using Eclipse There was No sign of error. Note:I have Also Created a html file to enter the USN Number.  Code:  package com.abc.error; import java.io.IOException; import java.io.PrintWriter; import java.sql.*; import javax.servlet.http.HttpServlet; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; public class GetResult extends HttpServlet {  /**  *   */  static final long serialVersionUID = 1L;  Connection con= null;  PreparedStatement pstmt=null;  ResultSet res=null;  public void init(){         try {             Class.forName("oracle.jdbc.OracleDriver");             con = DriverManager.getConnection("jdbc:oracle:thin:@//localhost:1521/XE","system","system");         } catch (ClassNotFoundException | SQLException e) {             e.printStackTrace();         }     }  @Override public void service(HttpServletRequest request, HttpServletResponse response) {     try     {            pstmt = con.prepareStatement("SELECT * FROM VTURESULT_AUG WHERE USN =?");         String key = request.getParameter("USN");         if(key.length()!=12){             response.sendRedirect("/ServletWithError/error.html");         }         else         {             pstmt.setString(1,key);             res =pstmt.executeQuery();             if(res.next())             {                 String usn = res.getString(1);                 String name = res.getString(2);                 int m1 = res.getInt(3);                 int m2 = res.getInt(4);                 int m3 = res.getInt(5);                 PrintWriter pw =response.getWriter();                 pw.println(usn+" "+name+" "+m1+" "+m2+" "+m3);             }         }     }     catch(SQLException | IOException e)     {         e.printStackTrace();     }   } }   Output:  java.lang.NullPointerException com.abc.error.GetResult.service(GetResult.java:36) javax.servlet.http.HttpServlet.service(HttpServlet.java:741) org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:53)

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


Why are the two following result different? The result of the following multiplication should be an integer anyway.  uint16_t test = 500.00 * 128.51; std::cout << test << std::endl; ----> 64254   but  float test = 500.00 * 128.51; std::cout << test << std::endl; ----> 64255

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


The last couple of days I've been trying to understand how the Stack Overflow page views counter works. I wish to add a views counter to a project of mine and investigating the options. Stack Overflow seems to be a good source of useful ideas. Needless to say I've browsed through all of the related questions here on Stack Overflow and on Meta Stack Overflow. I can't say I've found an explanation but some tips (presumably false leading) were given in this answer:  From what I can tell there is now a JavaScript section in each answer page (used to be CSS in 2008):

   The last part of the URL - a947 - seems to be dynamically generated. It is changed every 15-20 minutes and is the same for all questions and presumably users (I tried anonymous access, changing my IP address, it stays the same during the interval). In a comment to the answer  Jeff Atwood gave a bit of a hint:  our view counts are very very strict -- more akin to visits as they are unique per IP per 15 minute interval.  Observing things with Firebug reveals that this URL always returns "204 No Content". So my first idea was that the browser is likely not to retrieve that counter URL on subsequent page requests until the random code changes, thus preventing duplicate counter hits already on the client side for that 15 minutes interval. Watching the things with Firebug doesn't seem to confirm that theory:  As you can see the counter URL is retrieved again and again (even if I don't refresh the page with F5 but just click the page link in the title). More to it. I tried to recreate the same scheme in a test project also returning 204, and I confirm that the counter URL is retrieved again and again. No browser caching. More peculiar, Firefox for some reason calls the URL twice (the number is always even):  At this point the idea behind this counter URL is a mystery to me. What is the point of that last changing part of the URL if it's the same for all questions and users and does not prevent repeated requests from the client-side? In that question a possible explanation is given:   I think I know the answer - they are analyzing the IIS log as Ope suggested. Hidden image src is set to  code] [Random code] is needed because many people may share the same IP address (in a network, for example) and the code is used to distinguish users.  I'm not sure I understand this and I somehow feel it's off course. Can somebody or perhaps the Stack Exchange Inc. folks explain what and how they are doing with the views counter? I'm not trying to understand how it works in order to start gaming the system, I only wish to learn how these things are done. I hope Stack Exchange Inc. won't mind revealing some secrets. UPDATE: I'm beginning to suspect this changing value at the end of the url is used to help aggregate the collected data by dividing time in 15-minute-slots. Still thinking in what way exactly... UPDATE 2: So I've tried my test project with different browsers to see if 204 No Content would result in browser caching. It doesn't. The counter URL is retrieved again when the page is requested next time, but the value at the end of the counter URL is not changed. I tried with Internet Explorer 8 and the current versions of Firefox 3.6, Opera, Safari and Chrome. The behavior is identical and not surprising actually since the response for 204 doesn't contain the "Expires" header (neither does a live response from stackoverflow.com) so there is no reason for the browser to cache the response. I kindly ask again the nice folks what is then the reason of that changing value of the counter URL? It doesn't force temporary browser caching so the reason must be elsewhere.

I saw it's not just a page views number, because, if I press F5 several times, it won't increase the number of views.  They could store my IP address in a table, but wouldn't that make it slow? They would need to query a database one more time for each request.


can anybody help me with what this means: -rwxr-xr-x 1 root root 920788 Mar 28 2013 bash and explain it in detail.


Some people don't have the ability to make up their mind. They keep swapping between two (or even more options). I'm not looking for a description of the type of person (like indecisive), but for a verb to describe this kind of behaviour.  Example sentence:     Bob's {swapping behaviour} is really annoying me!

Let's say I have an important decision to make and I can't decide between two competing things (like break up with a girl or not break up with her). What would be a word/idiom to express that?


How can the  change in the medium when we know that it is always equal to $c$? If we say the speed of light is changing in the medium, it will contradict the Einstein's law of special relativity.

I know that if we solve the Maxwell equation, we will end up with the phase velocity of light being related to the permeability and the permittivity of the material. But this is not what I'm interested in - I want to go deeper than that. We know that the real speed of light is actually not changing, the decrease in speed is just apparent. Material is mostly empty, the light will still travel with $c$ in the spacing. The rare atoms will disturb the light in some way. So I am interested in how the atoms affect the light. Photon absorption-emission theory Some textbooks that I read explain it in a way kind of like this: In a material the photons are absorbed by atom and then re-emitted a short time later, then they travel a short distance to the next atom and get absorbed&emitted again and so on. How quickly the atoms in a material can absorb and re-emit the photon and how dense the atoms decides the apparent speed of light in that material. So the light appears slower because it has a smaller “drift speed”. Interference theory But recently I realize an alternative explanation: Atoms respond to the light by radiating electromagnetic wave. This “new light” interferes with the “old light” in some way that results in delayed light (advanced in phase), this can easily be shown by using simple phasor diagram. Consequently effectively the light covers a smaller phase each second, which gives the impression of a lower phase velocity. However the group velocity is changing in a complicated way. I think that the first explanation does not explain the change in phase velocity of light. if we consider light travelling into a slab of negative refractive index non-dispersive material, let’s say the light is directed perpendicular to the slab. The phase velocity’s direction will be flipped, but group velocity’s direction in the material will not change. Only the second explanation can explain the flipped phase velocity direction. I guess that the velocity that we get in the first explanation is actually belongs to the group velocity. It makes sense to me that the front most of the photon stream determines the first information that the light delivers. So the question is What really cause the phase velocity of light to be decreased?  "drift velocity" of photons (they aren't the same photons, they are re-emitted all the time) phase difference between absorbed and emitted light something else  And also, I still don't really understand detailed explanation of the absorption-emission process for small light's wavelength (for large lambda compare to the atoms spacing, the photons will be absorbed by the phonons). The dispersion relation that we know is continuous and also some material is non-dispersive, therefore the absorption process must occur in all frequency for a certain range. So definitely it doesn't involve the atomic transition, otherwise it will be quantized. My guess is that the relevant absorption process gets smooth out by the dipole moment. What makes the spectrum continuous? EDIT: link for dispersion relation:


I thought this is italic theta. I tried \textit{\theta}, \textit{$\mathcal{O}$} . But, I couldn't get this letter.

I know what my symbol or character looks like, but I don't know what the command is or which math alphabet it came from. How do I go about finding this out?


First graph was given by its adjacency matrix, While the second one was given by its edges coordinates, as the theory says graphs are isomorphic by the number of their nodes (one of the signs), as can be seen both have the same number of  the nodes, but my professor wants me to find 1-to-1 correspondence between these two graphs, how can it be done?

Suppose that we are given two graphs on a relatively small number of vertices. Here's an example:    Are these two graphs isomorphic? (That is: is there a bijection $f$ from $\{A,B,\dots,I\}$, the vertex set of the first graph, to $\{1,2,\dots,9\}$, the vertex set of the second graph, such that $vw$ is an edge of the first graph if and only if $f(v)f(w)$ is an edge of the second graph?)   If not, how can we tell? If so, how can we tell—and how can we find an isomorphism?     This question comes up a lot, usually asking about specific examples of two graphs which may or may not be isomorphic. Sometimes, the fiendish teacher of graph theory will even give three or more graphs and ask "Which of these are isomorphic?"  I'm asking this question so that we can provide  to questions of this type which would be worth linking to when specific instances of this question come up. So all improvements and/or suggestions are welcome!


In order to preserve this state, please don't commit any edits to this question.  The question  begins with the text, "Hi All", but the editor strips seems to strip it out:  Post: Editor:  Are greetings stripped from posts automagically nowadays? Or is this a bug that the text differs?

I stumbled upon the following issue.  starts out with "Dear friends", as can be seen in the image below (and hopefully by following the link).    However, when I go to edit the question for some clean-up, I don't see this in the source of the question:    My first guess was that a suggested edit is hanging around somewhere, but I don't see one. So, what's going on? Am I the only one seeing this? Bug? Cache? (New feature? Are we all friends now? ;) )


In connectedApp setting, there is an option called require secret for web-server flow. If I understand that correctly, if we choose that option, when using web-server flow, after authentication, the authorization code will still be sent to the client app. But the client app will only need the authorization code to request for access token - instead of authorization code + client secret.   This flow is actually pretty interesting to me? If the client app doesn't need to provide a client secret to verify, how does the extract round of authorization code provide extra security? Is it almost the same thing as user-agent flow?

After looking into the different OAuth types and reading , I'm still confused on the specific pros and cons of user-agent vs web server flows.  The best explanation I can find says that user-agent tends to be used for mobile but it seems that they can both be used for desktop.   What makes it more appropriate to use one over the other in certain scenarios?


Find the number of monic square-free polynomials of degree j >=1 over the finite field GF(q) ?  I have no idea how to approach this. I was thinking if there was a way to write a monic polynomial uniquely, it might lead to something.  Could someone help with this

I'm trying to figure out how many squarefree polynomials there are of a fixed degree over $\mathbb{F}_2$ specifically (and in general, over any finite field). Looking at some low-degree examples seems to suggest that half of the polynomials of any given degree are squarefree, but I'm not sure how to prove this, or whether the pattern continues at all. I'm considering the possibility of using the formal derivative, and the fact that a polynomial is relatively prime to its formal derivative iff it is squarefree, but I don't see how to proceed with this. So is there a known formula?


What is your recommended tutorial for character creation, rigging and weight painting?  I have watched so many YouTube tutorials on this and most don't go into detail or explain at all WHY they are doing something. Which to a new blender user, would not make sense. As I'm working on my own model not on whatever they are doing in the tutorial some things just go wrong.  I have been working on making a model from scratch to make for VRChat expecting it to only take 3 days has now taken now over a week working on it 12 hours a day. Even some all-nighters. No, this is not an exaggeration.  I've remade/re-edited my model about 25 times now and the joints still are very jagged when they move in VRChat.   I do best learning with Pictures and words rather than just textbook-words. Video is ok too.   Yes, posting on these forums is helpful at times but I'd much rather prefer for my problem to be solved as soon as possible. Rather than waiting for a response and in the mean-time ruining my character more in order to try and work out a solution myself. Most of my problems come from not pressing 1 key.  I don't want someone to do it for me, I want to learn how to do it myself.  I honestly just want to know how to make my character perfectly. I will buy any plugins or pay a tutor or video service to just explain it to me properly.   Is there some kind of website where I can pay to ask a blender-pro any question about blender in exchange for money? I know that my problems take a long time to explain especially because I want a screen shot or step-by-step walkthrough of how to do something or how to fix something with the reason WHY and just explaining what each tool does. It doesn't have to go into a lot of detail just enough for me to understand.  Can anyone give me some advice or links to where I can accomplish this?

Since asking for tutorials, videos, resources, links to other content or downloads is considered off topic here, this is a specifically created Community Wiki which gathers resources for Blender and it has been approved by the .  Just write in the appropriate answer/section. If you have concerns, questions, post a  question, so we don't clutter the comments, but you can link your meta question from the comments.  Questions regarding such resources are not allowed anymore, except for very specific and on topic requests (ask on  if you're unsure about your question). Follow the instructions made in the question about how to post, what can be posted, etc.  Learning             Assets    (also see: )   Reference Images/Blueprints (also see: )    Tools    (also see: )      Other   Special Interest ()     Also see the .


I decided to learn topology from a , however, I have come across a concept that seems to be defined twice in two different ways. At one point in the document it defines a subset of $\mathbb{R}$ to be open if every point in it has a neighborhood (my simplification for the purpose of conciseness). In another place, it has the following text (this is when defining a topological space): "A topological space is a set X together with a collection O of subsets of X , called open sets , such that..." (then the text lists the three axioms of topological spaces), which one may interpret as defining open sets to be sets satisfying the axioms of a topological space, hence my confusion. Thanks in advance

I'm having trouble understanding the notion of an open set when applied to a space without a metric defined on it. I have read that all metric spaces are naturally a topological space, but the converse is not true. Topological spaces definitions I have read use the idea of open sets, and I can't understand this abstract idea of openness or closedness of a set without having a notion of distance.  I can understand the notion of open and closed sets in a metric space from the definitions I have read using the idea of distance and open balls. So for example given a metric space $M$ with the metric $d$, we can say a set $U \subset M$ is open if $\forall x \in U, \exists B(x,r) \subset U$, which says that we can choose any point within the set $U$ and there will always be some sufficiently small distance $r$ that we can move in any direction to another point $y$ that is also contained within $U$. This has an intuitive conceptual meaning in my head regardless of space $M$ or metric $d$.  Now take the example of a space $F$, a fruit bowl with $3$ apples, $3$ oranges and $2$ bananas. There is no metric defined on the space $F$ to determine a distance between its elements, the fruit. Can we define an open set on this space? In order to be a topological space we need to be able to define open sets right?


I configured a Virtual Private Server as send-only mail server with exim4. Anyway, when I send an email to a Gmail account, it is marked as spam, because "it violates the guidelines for the sender recommended by Google.".   I checked if my domain name isn't blacklisted, and it isn't.  I also create a record A with my domain which I used as reverse DNS for my VPS.  I can't figure out the problem. Can anyone help me?

This is a  about avoiding outgoing mail being classified as spam.   Also related:                    I'm wondering how to prevent my emails from my site being marked as spam? I'm using sendmail.  I'm trying to send emails through my ruby-on-rails application. The mails are all written in swedish (if that does make a difference?). I don't know why they keep getting marked as spam.  Are there any things that I can do to minimize the risk?


I have photoshop CS6 installed and working on Wine1.7. It's actually surprisingly smooth. The only issue I have now is that the fonts are a bit limited, and I'm not sure if it's an issue with wine or with the photoshop installation. I tried copying some fonts to the ~/.wine/drive_c/windows/Fonts/ directory but they are not appearing in photoshop.  What should I do?

Is there a way to install fonts on wine?   I'm looking to install fonts so i can use them to render text differently on various apps. Specifically myriad.


I love the auto-correct feature, once I got used to not going "AH! Typo!  furious backspacing Retype correctly!"   I have one beef though.  It seems that the typos I make are nonstandard enough that about 50% of the time, Auto-Correct chooses the wrong word.  This irritates me even more than making a typo in the first place.  It seems to happen often with double letter endings where I miss one, but that's certainly not the only case.  Example:  When typing the word 'will' I often type 'wil', I have no idea why.  Auto-Correct zaps this to 'ail'.  So then, instead of backspace, type another L, space, keep going, I have to delete the entire wrong word.  The reason I am asking here is that I don't want to add misspelled words to the dictionary, I want to train the behavior of the Auto-Correct engine itself.    Is this possible?  I can't imagine that there's no capability for learning in that algorithm.  I dream of a time when I can just mash away at the keyboard, and the computer just knows what I mean and records my rhoughts (There's another one:  it gets instantly set to 'roughest' instead of 'thoughts') accordingly.

I'm running into an annoying issue with OS X's automatic spelling correction where the word nala gets automatically corrected to napa.  I've tried adding nala to my custom dictionary under ~/Library/Spelling/LocalDictionary but it still reliably makes the correction anyway.  How do I configure OS X to not automatically correct a given word short of turning off automatic correction entirely which is not really desirable?


I understand about self invoking anonymous functions like so:  (function () {     //... })();   and that most of the time they are used for creating closures and abstracting variables in frameworks. However I've also seen sources in different sites that declare anonymous functions but they do not invoke them. I'm curious as to how those are used. Are they invoked when the script is loaded? Note that in the sources tab they don't look like .js files. Instead they have a name like so:  extensions::utils, or extensions::Event etc.   They look like they're part of some kind of framework/library? I'm not sure. For example the extensions::Event has this code inside:  (function($Object, $Function, privates, cls, superclass) {'use strict';   function Event() {     var privateObj = $Object.create(cls.prototype);     $Function.apply(cls, privateObj, arguments);     privateObj.wrapper = this;     privates(this).impl = privateObj;   };   if (superclass) {     Event.prototype = Object.create(superclass.prototype);   }   return Event; }) //<-Self invocation missing.   As you can see this is just declared but not used. The only thing I can think of is that this anonymous function is actually assigned to a variable called Event and is part of the extensions object or something?

In javascript, when would you want to use this:  (function(){     //Bunch of code... })();   over this:  //Bunch of code...


This is an old 2GB pen drive I have. I performed a full format on it while in Ubuntu 16.04, then changed its partition to Fat32 using GParted and used Ubuntu's startup disk creator to create an Ubuntu 16.04 installer USB.    Now when I open GParted, I'm shown this error:  I click 'Ignore' and am shown this:     I click 'Ignore' again and GParted shows that it can't recognize the filesystem and also it shows that it is an 8GB pen drive, when in reality it is a 2GB pen drive.     Nautilius shows it correctly as a 2GB pen drive.     Is something wrong here? Is it normal for Ubuntu to create the sdb1 and sdb2 partitions? Why can't it recognize it's own filesystem? Is that why the pen drive size is being wrongly detected?

I was using:  dd  if=/path/to/my/ubuntuiso/ubuntu.iso  of=/dev/sdb1  bs=4M  &&  sync   In order to create bootable Ubuntu USB drives on older Ubuntu versions. It was working perfectly. Sometimes I used the Startup Disk Creator program, which  worked well.  But when I use the same methods on Ubuntu 16.04 LTS, I get some warnings while formatting it afterwards.   The installation media works as expected, but when I try to format that USB stick after my work is done, I get the following warning :    The partitioning of that Pendrive looks strange :    And it also shows my 16GB pendrive as 64GB.  After struggling a lot with Gparted, I will somehow format it. But Why is it happening like this ?? Is there any better methods of creating bootable Ubuntu in 16.04 ?  EDIT : there is a related question . But my question is not about how to format it properly. My question is "How to create a bootable USB without that errors." & "Wht are the causes of that error"


I am working on a basic Hackerrank problem where we append an element to the end of the linked list.   /*   Insert Node at the end of a linked list    head pointer input could be NULL as well for empty list   Node is defined as    class Node {      int data;      Node next;   } */ Node Insert(Node head,int data) {     if(head == null) {         Node node = new Node();         head = node;         head.data = data;         head.next = null;         return head;     }      while(head != null) {         head = head.next;     }      head.data = data;     head.next = null;     return head; }   For some reason, this solution does not compile. I was looking problems other people solved, and they used a temporary node in the non-empty linked list solutions.

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


From this link:      Service runs in the main thread of its hosting process; the service   does not create its own thread and does not run in a separate process   unless you specify otherwise.   This means that the service runs in the main thread of the app that starts it. If so, why doesn't the app get blocked when the service is running?  Any help will be appreciated.

What is the technical difference between a process and a thread?  I get the feeling a word like 'process' is overused and there are also hardware and software threads. How about light-weight processes in languages like ? Is there a definitive reason to use one term over the other?


Could I attune a magical item to my pet cat? There don't appear to be any base requirements for attunement.

We have previously determined that  or  can attune to magic items, but one of those is a sapient creature, and the other "always obeys your commands".  A paladin's steed (per the Find Steed spell) is also 'unusually intelligent' and falls within the score range for sapient creatures.  But what about a regular old animal? If my ranger has a wolf companion, can he make that wolf attune to, say, an Amulet of Health? According to the Beast Master archetype, a companion animal "obeys your commands as best it can".  Is spending an hour 'focused only on the item' (as required for attunement) something a beast can manage?  Or what if it's not an Animal Companion, but just a riding horse, a pet dog, a trained magpie?  I know, probably this is going to be down to the DM to determine, but is there any guidance we can use to help decide whether my cat can attune to an item, and whether rubbing it with catnip would help?


I deleted my recovery partition on accident when I was installing Kali. I've tried a method that was posted to this site, but I believe it only works for Windows 7. Any help would be greatly appreciated!

I have Kali Linux currently running on my laptop. I want to install Windows 7. I don't have CD ROM ,how do I make bootable USB having Windows ISO?   Which software will help me?  Or just how to make usb bootable?  I want to install Windows 7 again.


I'm working on a website that should be very safe for the users, so I need the hash the passwords. Usually I'm using the MD5, but I read that it doesn't safe anymore. So I tried PHPass, but then I read that it also has been cracked. So I tried password_hash() of PHP 5.5, but I use HostGator, and the PHP there is 5.4. Also I want to be able to add salt without knowing it (like time() * userid()), like in the password_hash().   The hash strength is very important to me because I want to be 100% sure that my users are safe. So is there a way that very safe and not something like SHA that will be hacked soon?

It is currently said that MD5 is partially unsafe. Taking this into consideration, I'd like to know which mechanism to use for password protection.  This question,   suggests that hashing multiple times may be a good idea, whereas  suggests using salt.  I'm using PHP. I want a safe and fast password encryption system. Hashing a password a million times may be safer, but also slower. How to achieve a good balance between speed and safety? Also, I'd prefer the result to have a constant number of characters.   The hashing mechanism must be available in PHP It must be safe It can use salt (in this case, are all salts equally good? Is there any way to generate good salts?)   Also, should I store two fields in the database (one using MD5 and another one using SHA, for example)? Would it make it safer or unsafer?  In case I wasn't clear enough, I want to know which hashing function(s) to use and how to pick a good salt in order to have a safe and fast password protection mechanism.  Related questions that don't quite cover my question:


So I am just making a little blog project with codeigniter. What I am trying to do is once a comment is added, I want to be able to delete it. Deleting comments works for older comments, but not for the newer ones added. In order for them to be deleted the page has to be refreshed. I have looked through some answers on stackoverflow already but none seem to be my problem. The problem is when I click remove on my new comment, its not registering that I have even clicked the element. If you look below I added a console.log test which should show up when I click the element, but nothing happens. How would I fix this?  EDIT: I noticed something in the console (Using firefox). Near to the remove element there is a black little box with "ev" written in it. It comes up next to the other comments but not the new comment.  EDIT: Ok I should have done a little more digging, I found the answer:  Change   $(".com-delete").click(function()   TO   $(document).on("click",".com-delete",function()   Code:

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.


My question is quite simple: I've installed virtualenv with the following command: sudo  -H pip3 install virtualenv  It seems to be wrong, because in the tutorial that I watch pip downloads other stuff than on my pc. How can I undo it? Thx for your help and stay healthy!

I have accidently installed Python packages to my system using pip instead of apt-get. I did this in two ways:   using an older version of virtualenv, I forgot to append --no-site-packages when creating the virtualenv - after that when I called pip install, the Python packages where installed to the system rather than the virtualenv in a correctly setup virtualenv, I typed sudo pip install somepackage - the sudo installed to the system rather than the virtualenv   I happened to notice this because I typed pip freeze outside a virtualenv, and spotted some Python packages listed that shouldn't be there. So now my question is:   how do I identify all Python packages that have been erroneously installed on the system (that is, Python packages that appear in the pip freeze list, but were not installed with apt-get)? how do I remove them?


I see this since yesterday:        Its tooltip says:     we have posts flagged for moderator attention, perhaps you can help   But when  I see empty page i.e. no flags:        After clicking the number isn't showing for a while but then it come back.  Can the zombie flags please be put to an end? :)

It looks as if the 10k-tools flagged post list is b0rken.  Next to the review link in the toolbar there is a flag counter showing there are 10 flags to be reviewed:    Clicking on that flag counter leads to an empty page:        The moment I visit that page (through clicking on the flags counter, or by going to the review queue first then clicking on Tools, selecting the flags tab if not already selected), the flags counter disappears from the toolbar:    but after a while (half an hour, an hour?) the flag count re-appears in the toolbar.  Either the counter is wrong (presumably taken from a Redis cache somewhere) or the 10k flag review page is falling over every time someone tries to load it.  This at first appeared to happen only on Meta, on Stack Overflow the flags page has plenty to review. However, there are now  on Stack Overflow.


list1=['f','l','a','m','e','s'] #This is the predefined list list2=['e','e','f','a','s','a'] #This is the list with repitition x=list(set(list2)) # I want to remove duplicates print(x)   Here I want the variable x to retain the order which list1 has. For example, if at one instance set(list2) produces the output as  ['e','f','a','s'], I want it to produce ['f','a','e','s'] (Just by following the order of list1). Can anyone help me with this?

Is there a built-in that removes duplicates from list in Python, whilst preserving order? I know that I can use a set to remove duplicates, but that destroys the original order. I also know that I can roll my own like this:  def uniq(input):   output = []   for x in input:     if x not in output:       output.append(x)   return output   (Thanks to  for that .)  But I'd like to avail myself of a built-in or a more Pythonic idiom if possible.  Related question:


I get this error when I insert an interstitial ad. Help me  @Override protected void onCreate(Bundle savedInstanceState) {     super.onCreate(savedInstanceState);     mBinding = DataBindingUtil.setContentView(this, R.layout.module_home_activity_home);     mViewModel = ViewModelProviders.of(this).get(HomeViewModel.class);     getLifecycle().addObserver(mViewModel);      initView();     subscribeUi();      MobileAds.initialize(this, "ca-app-pub-3940256099942544~3347511713");      mInterstitialAd = new InterstitialAd(this);     mInterstitialAd.setAdUnitId("ca-app-pub-3940256099942544/1033173712");     mInterstitialAd.loadAd(new AdRequest.Builder().build());      Button tvOk = (Button) findViewById(R.id.tvOk);      tvOk.setOnClickListener(new View.OnClickListener() {         @Override         public void onClick(View v) {             if (mInterstitialAd.isLoaded()) {                 mInterstitialAd.show();             }         }     });      mPermissionReqHandler = new PermissionReqHandler(self()); }   Logcat Message:      FATAL EXCEPTION: main Process: com.xxx.xxx, PID: 29573 java.lang.RuntimeException: Unable to start activity ComponentInfo{com.xxx.xxx/com.xxx.xxx.app.tally.module.home.HomeActivity}: java.lang.NullPointerException: Attempt to invoke virtual method 'void android.widget.Button.setOnClickListener(android.view.View$OnClickListener)' on a null object reference     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2817)     at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2892)     at android.app.ActivityThread.-wrap11(Unknown Source:0)     at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1593)     at android.os.Handler.dispatchMessage(Handler.java:105)     at android.os.Looper.loop(Looper.java:164)     at android.app.ActivityThread.main(ActivityThread.java:6541)     at java.lang.reflect.Method.invoke(Native Method)     at com.android.internal.os.Zygote$MethodAndArgsCaller.run(Zygote.java:240)     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:767)  Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'void android.widget.Button.setOnClickListener(android.view.View$OnClickListener)' on a null object reference     at com.coderpage.mine.app.tally.module.home.HomeActivity.onCreate(HomeActivity.java:86)     at android.app.Activity.performCreate(Activity.java:6975)     at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1213)     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2770)     at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2892)      at android.app.ActivityThread.-wrap11(Unknown Source:0)      at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1593)      at android.os.Handler.dispatchMessage(Handler.java:105)      at android.os.Looper.loop(Looper.java:164)      at android.app.ActivityThread.main(ActivityThread.java:6541)      at java.lang.reflect.Method.invoke(Native Method)      at com.android.internal.os.Zygote$MethodAndArgsCaller.run(Zygote.java:240)      at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:767)

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


I'm looking for a recommendation for the type and brand of tires to purchase for a vintage 70s "Sport 103" Peugeot.  For casual recreational usage.The original tires were 27 x 1 ¼  gum sided. Do I need to be aware of any discrepancies between older and newer tire mounting configurations on the rims. Is there a brand and model that is made specifically for fitting on older bikes?

I live in a city with plenty of cycling shops, but they are all out of 27 x 1 1/4 tires. Each shop gives me a different answer about the possibility of using a different size of tire. Can I fit a different size onto an old 27 x 1 1/4 rim?


I installed Ubuntu 13.10 alongside windows 8.1 in a separate partition. But on start up , windows 8.1 automatically boots without giving me options to choose between windows and Ubuntu. Plz help! I want to choose OS on start up!

I installed Windows 7, which ate Ubuntu's boot file. When starting up the computer, it now goes straight to Windows, without giving me the option of booting Ubuntu.   How can I get Ubuntu back?


I'm trying to make code to ask for your name, which then says, "Hello, _____, my name is Dolly." Then three buttons appear with options of what to do to Dolly.   Is there any way I can add a function onclick of the spawned buttons to create a response accordingly? I apologize if it's a bit messy and not dry, I'm kinda new to this.

Please enter your name
         <input type="text" id="name" value="" placeholder="Please enter your name">          <button id="submit" onclick="yourName()">Enter</button>


In order for Territory Assignment rules to fire on Account creation and Update, I have got 2 Classes working (with Triggers), however I am struggling to create a Test class for these, any help would be greatly appreciated. Class that calls the queueable callout: public class RunTerritoryRulesCallout {      public static void RunTerritoryRulesCallout(List<Account> AccsToUpdate){          //run ETM assignment rules         Map<ID, Account> AcctMap = new Map<ID, Account>(AccsToUpdate);         Set<String> AccIDs = new Set<String>((List<String>) New List<ID>(AcctMap.keyset()));           if(!System.isQueueable()){                           RunTerritoryRules Job = new RunTerritoryRules();                 Job.accntIds = AccIDs;                                     System.debug('Queuing ETM assignments');                 System.enqueueJob(job);         }        }    }  The callout class: public class RunTerritoryRules implements Queueable, Database.AllowsCallouts  { public Set<String> accntIds = null; private String sessionId = null;     public void execute(QueueableContext context) { sessionId = Page.GetSessionId.getContent().toString();          List<String> lstAccString = new List<String>();     if(accntIds != null){         for(String accId:accntIds){             lstAccString.add(accountTag.replace('{ACCID}', accId));          }     }      requestTemplate = requestTemplate.replace('{ACCLISTS}', String.join(lstAccString, ' ')) ;     requestTemplate = requestTemplate.replace('{SESSID}', sessionId) ;             HttpRequest request = new HttpRequest(); request.setEndpoint(System.URL.getSalesforceBaseUrl().toExternalForm()+             '/services/Soap/u/41.0/'+UserInfo.getOrganizationId());     request.setMethod('POST');     request.setHeader('Content-Type', 'text/xml;charset=UTF-8'); request.setHeader('SOAPAction', '""');     request.setBody(requestTemplate); String s = String.valueOf(new Http().send(request).getBodyDocument());     System.debug(s); } String accountTag = '<urn:sObjects> '+                         '<urn1:type>Account</urn1:type>  '+                 '<urn1:Id>{ACCID}</urn1:Id>   '+                     '</urn:sObjects> ' ;     String requestTemplate = '<soapenv:Envelope '+             'xmlns:soapenv="http://schemas.xmlsoap.org/soap/envelope/"'+             ' xmlns:urn="urn:partner.soap.sforce.com"'+             ' xmlns:urn1="urn:sobject.partner.soap.sforce.com">'+                             '<soapenv:Header> '+                               '<urn:AssignmentRuleHeader> '+                                   '<urn:useDefaultRule>true</urn:useDefaultRule> '+                                  '<urn:assignmentRuleId></urn:assignmentRuleId> '+                               '</urn:AssignmentRuleHeader>  '+                               '<urn:SessionHeader> '+                     '<urn:sessionId>{SESSID}</urn:sessionId> '+                               '</urn:SessionHeader> '+                            '</soapenv:Header> '+                            '<soapenv:Body> '+                   '<urn:update> '+                    ' {ACCLISTS}'+                                '</urn:update> '+                            '</soapenv:Body> '+                         '</soapenv:Envelope>';}

This is a canonical question and answer developed by the community to help address common questions. If you've been directed here, or your question has been closed as a duplicate, please look through the resources here and use them to shape more specific questions. To browse all canonical questions and answers, including more unit test resources, navigate to the  tag.  This canonical question is intended to address several classes of common questions by providing a quick summary and links to comprehensive resources:   How do I start writing my first unit test?  How do I unit test this code?  I need help writing this unit test.   Salesforce Stack Exchange looks for detailed, specific questions that the community can help you with, and can't write tests on your behalf. We feel that working with the resources below can help you get started, and we encourage you to make an attempt to write your test and return to SFSE with your specific questions when you encounter challenges you can't resolve.


I am trying to create a program, that takes asks the user to enter a Contact name, and a contact number, and then stores that contact in my ArrayList entries. Once the user has entered the first contact, they are given the choice to add another contact to the array list, or to not add any more contacts, exiting the loop, and simple displaying all of the contacts stored in entries.  I am currently having trouble exiting my while loop, the first contact adds correctly to the array list, and then displays the "Add Another?" message, however from there it falls apart, if i type Y, the console simply just hangs with the cursor flashing, instead of asking for the next contacts name and number, and if i type N, it once again just hangs and does nothing, instead of exiting the loop and displaying the contents of  my ArrayList like intended.  Any help towards solving this issue would be much appreciated! I have a feeling it may be something to do with my loop, but can't for the life of me see what!  Thanks in advance!  while (addMore != false)     {         System.out.print("Contact name: ");         String name = sc.nextLine();         System.out.print("Contact Number: ");         String TelNo = sc.nextLine();          // add the user inputted contact to ArrayList entries.         entries.add(new TelEntry(name, TelNo));           System.out.print("Add Another?(Y/N): ");         if(sc.nextLine() == "N")         {             addMore = false;             break;         }          else if(sc.nextLine() !="Y" && sc.nextLine() !="N")         {             System.out.println("Please Select Y or N");         }          addMore = true;      }      // FOR LOOP TO PRINT ALL ENTRIES IN ARRAY     for(int i=0; i<entries.size(); i++)     {         System.out.println(entries.get(i));     }

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


I've studied simple harmonic motion and the relation that force $\mathbf F$ is proportional to $-x$ and time period of motion. But if in some other motion, $\mathbf F$ is proportional to some other power of $x$ say $- \mathbf F$ proportional to $-x^3$, and we just doubled the amplitude of motion, then how would the time period change?

How would I find the period of an oscillator with the following force equation?  $$F(x)=-cx^3$$  I've already found the potential energy equation by integrating over distance:  $$U(x)={cx^4 \over 4}.$$  Now I have to find a function for the period (in terms of $A$, the amplitude, $m$, and $c$), but I'm stuck on how to approach the problem. I can set up a differential equation:  $$m{d^2x(t) \over dt^2}=-cx^3,$$  $$d^2x(t)=-{cx^3 \over m}dt^2.$$  But I am not sure how to solve this. Wolfram Alpha gives a particularly nasty solution involving the hypergeometric function, so I don't think the solution involves differential equations. But I don't have any other leads.  How would I find the period $T$ of this oscillator?


I would like to know of a good and easy-to-use application to create simple but visually appealing vector figures such as spheres, planes, lines.  It should permit transparencies for example, and 3D coordinate representation to be able to show concepts in the 3D space, such as tangency or crossing.  Thanks!

I would like to have suggestions of good software for drawing illustrations in research papers. I already know about , but this works only on Linux and is at times, clunky when it comes to text. Moreover the resolution is not always perfect making it difficult to manoeuvre the objects. Besides it is tough to learn and master, with all its weird click procedures.   I would love to know about better alternatives. Not talking about graphs here, just block diagrams and explanatory illustrations.


When I run a function in js it seems to work fine but will this be fine?  function myfunction(){ }  VS  var myfunction = function(){ }  Because both are called the same so does it make no difference? Sorry new to js so i'm just making sure it's good to learn this style. (The first function is what i'd prefer to use.)

I've recently started maintaining someone else's JavaScript code. I'm fixing bugs, adding features and also trying to tidy up the code and make it more consistent.  The previous developer used two ways of declaring functions and I can't work out if there is a reason behind it or not.  The two ways are:  var functionOne = function() {     // Some code };     function functionTwo() {     // Some code }   What are the reasons for using these two different methods and what are the pros and cons of each? Is there anything that can be done with one method that can't be done with the other?


this is my code,   \begin{tikzpicture}  \node (A) at (-4, -3) {A};  \node (o) at (0, 0) {o};  \draw [name path = circle] (o) circle (3.5cm);   \end{tikzpicture}   Given a point A outside a circle, I want to:    draw a tangent line to the circle which come through point A.  find the intersection point (between the tangent line and the circle) and denoted this point as B. (I need to use this point to connect to another point later).  Is there a way to do it? Thanks. :)

I'm trying to draw a tanget on a circle, but I'm not happy with the result I get from the tangent option.    particularly, I'd like to have the lines ending smoothly in the circle. The problem is shown enlarged here:      Here is the code for this mininmal example  \documentclass{standalone} \usepackage{tikz} \usetikzlibrary{calc}  \begin{document}   \begin{tikzpicture}[thick]     \node[draw,circle,xshift=2.2cm] (big) [minimum size=25mm] {};     \node[draw,circle] (small) [minimum size=2mm] {};     \draw (small.south) -- (tangent cs:node=big,point={(small.south)});     \draw (small.north) -- (tangent cs:node=big,point={(small.north)},solution=2);    \end{tikzpicture} \end{document}   I'd greatly appreciate any advice allowing me to do this!


I have been struggling with the following for quite some time now. If anyone can give me some help, it will be much appreciated:  Let $f$ bounded, measurable and $E$ be a set of finite measure. Let $A \subset E$ be measurable. Prove that:  $\displaystyle \int_{A} f = \int_{E} f \chi_A $

Let $f$ be a bounded measurable function on a set of finite measure $E$.  For a measurable subset $A$ of $E$, show that $\int_A f = \int_E f \cdot \chi_A$     Lemma: Let $f$ be a bounded measurable function on a set of finite measure $E$.  Suppose $A$ and $B$ are disjoint measurable subsets of $E$.  Then $\int_{A \cup B} f = \int_A f + \int_B f$.   My first approach was to view the problem like this utilizing the above lemma:  $$\int_E  f \cdot \chi_A = \int_{E\setminus A} f \cdot X_A + \int_A f \cdot \chi_A $$  I'm not really sure how the result follows from the above.


I have the following MWE for a Beamer presentation to create a simple color table:  \documentclass[xcolor={dvipsnames,table}]{beamer}  \usepackage{multicol} \usepackage{multirow}  \usepackage{array} \newcommand*{\arraycolor}[1]{\protect\leavevmode\color{#1}} \newcolumntype{A}{>{\columncolor{red!20}}c} \newcolumntype{B}{>{\columncolor{blue!20}}c}  \usepackage{makecell}  \mode<presentation> {     \usetheme[compress]{Singapore}     \usecolortheme{orchid} }  \begin{document}  \begin{frame} \centering \sffamily \arrayrulecolor{white} \arrayrulewidth=1pt \renewcommand{\arraystretch}{1} \rowcolors[\hline]{2}{.!50!White}{} \begin{tabular}{A|A|A|A|A|B|B|B}     \rowcolor{.!50!Black}     \multicolumn{5}{A}{\arraycolor{White}\bfseries {\footnotesize 14 affected subjects}} & \multicolumn{3}{B}{\arraycolor{White}\bfseries {\footnotesize 10 healthy subjects}}\\     \rowcolor{.!60!Black}     \multicolumn{3}{A}{\arraycolor{White} {\footnotesize Surface sampling}} & \multicolumn{2}{A}{\arraycolor{White} {\footnotesize Follicular extraction}} & \multicolumn{3}{B}{\arraycolor{White} {\footnotesize Surface sampling}}\\     {\tiny No lesion} & {\tiny \makecell{Non-inf\\lesion}} & {\tiny Inf lesion} & {\tiny \makecell{Non-inf\\lesion}} & {\tiny Inf lesion} & {\tiny Cheek} & {\tiny Forehead} & {\tiny Nose}\\     14 & 15 & 19 & 42 & 42 & 10 & 10 & 10\\     \end{tabular} \end{frame}   \end{document}   It produces this table, which shows some problems:    There is no space between multicolumn cells, see how "Surface sampling" and "Follicular extraction" are fused together.  When using \makecell to split a cell in two lines, the cell is grayed out, see "Non-inf lesion".  The last thing is I have to change the text size of each cell one by one, but I do not seem to find a way to apply that to a whole row; see how the second row should be all \footnotesize, and the third row all \tiny.  I would appreciate if someone could help me out with these problems. Many thanks!

When I try to use multicolumn inside a tabularx environment, I get this weird behaviour; where the column doesn't fill the whole width.  Anyone know why this is happening, and how I can fix it?  \documentclass[12pt]{article} \usepackage{tabularx,lipsum}  \begin{document}  \begin{tabularx}{\textwidth}{|X|X|}      \hline     \multicolumn{2}{|X|}{\sffamily Lorem ipsum dolor sit amet,}\\\hline     \multicolumn{2}{|X|}{\lipsum[2]}\\\hline      \sffamily Lorem av:&\sffamily Ipsum:\\     foo&bar\\\hline  \end{tabularx}  \end{document}


The door is locked and I can't read the last book how do I get the key to the door?

I cannot get the key off of Neloth at Tel Mithryn that would allow me to get the black book from his locked room. I think my game has a glitch. I am playing on PS3.


I'm reading Axler "Linear agebra done right" and in Chapter 1 he discusses subspaces and direct sum. My question is, are there subspaces of the infinite-dimensional vector spaces, e.g. a functional Banach space with sup norm $V$ that directly sum to the entire space $$V = U_1\oplus U_2$$ (except for trivial $U_1=\{0\}$, $U_2 = V$).

I am trying to prove that all vector spaces can be written as the direct sum of two subspaces.  My attempt: If each vector in vector space V can be uniquely written as the sum of two other vectors in V, the two vectors can be categorized into subspaces and thus V can be written as the direct sum of these subspaces. I am not sure how to show that this is true for all cases though. Edit Sorry for the confusion,to clarify I meantGiven a vector space V with a subspace W, prove that there exists a subspace W' such that the direct sum of W and W' is V.I am not sure about my proof method at all. Thank you.


I have the following setup:  Windows 8.1 on PC at Work. I use a local account.  My personal/private hotmail address, with all my personal data in Skydrive.  In Windows 8, I used to be able to have the Skydrive/Onedrive desktop app running, and connect it to my personal hotmail address. I could access, edit and sync my skydrive files at work: great!  Now upgraded to 8.1, it seems it is no longer possible? I installed the desktop app, but it cannot be opened?  As said here, it is all baked in:   Now, this is very annoying, obviously: I can no longer access my files!  Is there any solution to this?

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?


Is there any published, statistical data that shows social logins (such as OpenID, Facebook, etc.) are preferable over traditional username / password login with regards to registration rates?  For example, for the same amount of user visits (of the same profile such as age, gender, education, etc.), which would gain more registrations / sign-ups? The social logins or in-house username / password login?  If no such data are present, anyone care to provide some insights from your own website analytics for comparison? I ask this is because I personally asked a few of my users and neither was more favored over the other given in-house registration is simple to complete.

I am developing a niche social networking iPhone app of my own.   I was wondering if it would be best to allow the user to connect to social networks such as Facebook and Twitter to login to my app (and of course an eMail/Password fallback) or just go with regular eMail and Password login.  Any thoughts would be appreciated! :)


My GPA of bachelor is about 3.0, and I just want to know how much it would approximately be in German Grade? Would it be lower than 2.7 in German Grade? I have read other questions on this website, but none of them could help me, can you simply tell me how to convert GPA to German grading system?

I'm trying to figure out the equivalence between grade schemes in different countries.  According to some Google results:   If you are a U.S. citizen, you need a GPA of 3.2+ (it varies, some say 3.2 and some others say 3.6, etc) to apply for a position in the UK (job or university) where the prerequisite is to have a minimum grade of 2:1. In UK 2:1 is earned if you have a 60-69% of the points. I've read that 2:1 is the same as 67%. In Spain we use a grading scheme of 10 points. So according to (2), for have a UK 2:1 you need to have 6-6.9 points. If you are Spanish and have 6.7, when converting it to GPA the result is 1.5.   However, if you take the above points and treat them as a math equation, the final result will be GPA 1.5 = GPA 3.2, which doesn't make any sense.  GPA 3.2 = UK 2:1 UK 2:1 = Spain 6.7 Spain 6.7 = GPA 1.5   Replacing now...  UK 2:1 = GPA 1.5     GPA 3.2 = GPA 1.5   My question is if someone has a better explanation on converting grades obtained in different countries.


my java is not that great and i am trying to append the values in a linked list to a Text area however it is not displaying the values and i am getting an error but i cannot get to the bottom of it. Please help.  if (event.getSource()==btnDisplay)     {            String s = "";         Booking selectBooking = new Booking();          txtArea.setText("");         s="LessonType           No.InParty  Surname   Forename   InstructorCode \n";         txtArea.append(s);         s="--------------------------------------------------------------------------------\n";         txtArea.append(s);          ListIterator li = bookings.listIterator();         while(li.hasNext());         {             s = li.next().toString();             txtArea.append(s);         }      }   I am getting an error  s = li.next().toString();   Any help would be greatly appreciated. Thanks!!

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


I am trying to do some tests to see if I can execute a shell script in a variables contents, similar to the Invoke-Expression function in powershell. I am getting the contents of the variable from curl: a=$(curl https://some.site/test.sh) however, whenever I print out the variable, it only gives the last line of the shell script. Is there something I'm missing here? I'm using echo $a to print the variable.

Or, an introductory guide to robust filename handling and other string passing in shell scripts.  I wrote a shell script which works well most of the time. But it chokes on some inputs (e.g. on some file names).  I encountered a problem such as the following:   I have a file name containing a space hello world, and it was treated as two separate files hello and world. I have an input line with two consecutive spaces and they shrank to one in the input. Leading and trailing whitespace disappears from input lines. Sometimes, when the input contains one of the characters \[*?, they are replaced by some text which is is actually the name of files. There is an apostrophe ' (or a double quote ") in the input and things got weird after that point. There is a backslash in the input (or: I am using Cygwin and some of my file names have Windows-style \ separators).   What is going on and how do I fix it?


I'm looking for a book that I once read where wizards were divided into different factions.  One of those factions had a foot as a banner and they provide the source (e.g. the magic) that the other wizards need to do their magical works. If done properly they calculate how much a wizard needs.  Since they can only draw on magic (but not apply the energy themselves) they have to walk whereas other wizards can float/fly. Hence their order name.  Which book am I thinking is this?

I have a vague recollection of a book I devoured while in college; it was from the late 80's or early 90's. I remember that there were two 'classes' of mages, the ones who could harvest magical energy from the environment and supply that power to the other 'class' of mages.  The main character learned that he could reverse the flow and sap the other mage of his/her power. I also seem to remember that there was a lot of technological warfare and travel to the planets moon(s)?


When I ran Setup.exe on the Microsoft Office 2019 DVD, it automatically installed all the components with any user interaction - not even a single confirmation dialog.  How can I only install the components / programs that I wish to use?  Running E:\Setup.exe /? is useless.  I feel my computer is being force-infected with Microsoft's entire office ecosystem.  Is there a way of doing this without downloading another tool?

I just started the Office 2016 Setup/Installation on my Windows 10 PC. The installation worked fine and started automatically showing only this dialog:    But there are no additional settings possible! I need to choose which programs I want to install and also add additional tools that are often missing when doing a default installation.  How can I change the Office Installation Settings?   Choose programs to install Add/Remove Office Tools (Maybe) Office installation directory   When I check after the installation in the the windows settings, the Office can only be uninstalled - no modifications available:


Is there any difference between   SELECT * FROM TABLE_A a JOIN TABLE_B b   ON a.propertyA = b.propertyA           And the query  SELECT * from TABLE_A a, TABLE_B b where a.propertyA=b.propertyA.

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