I login to my SO mobile android app to browse for questions/answers for very specific tags every time. I wish there was an easy way to do that in one click: like a favorite tags or a recent tags menu/button somewhere on the home screen or feeds page. Right now I have to either search for tags myself or open a similar question, click on the tag to go to tag filter view and then retype the filter. I wish this 2 or 3 step process is reduced to a one click menu/option on the home page/menu.  Thank you guys. Again, the app is wonderful.

When using the web interface, there is a favorite tags section where you can select a list of tags that you view most frequently.  This has become a cornerstone of my normal  on stack overflow, but it doesn't look like this is possible in the Android app.  There should be a mechanism by which you can add some favorite tags to the nav bar. Clicking these tags will take you to a list of similarly tagged questions.  Perhaps also the feed should include a section for each favorite tag.  These would be presented on their own, much like how "hot new questions" and "new unanswered questions" appear in the feed.  Perhaps something like this:


Are there any stats on the user agents that visit the SE sites? So you can tell how many browsers/devices are used to visit SE sites.  Not only will this be interesting, but useful for stackapp developers to see how much of the SE community use the browser/device their app needs and how far their app has gone.  15 upvotes is quite a lot and yet answer from anyone!!!

Google Analytics (and some log parsers) will give you breakdowns on usage of different browsers, different versions of those browsers and screen resolutions.  I'm just curious to know what SO users user. Any chance we could get some stats on that? You may view this as commercial information, in which case I understand (as i'ts relevant to marketing/advertising).  I'm also curious to know the # of users who read and/or post from mobile devices and if so which ones.  UPDATE: Please refrain from personal anecdotes ("I use..."). I'm interested in actual usage, not personal stories. Thankyou.


I am running out of inodes. Only 11% available:  the-foo:~ # df -i  Filesystem               Inodes   IUsed   IFree IUse% Mounted on /dev/mapper/system-home 9830400 8702297 1128103   89% /home   Is there a way to solve this without creating and copying to a new partition?  Details:  the-foo:~ # tune2fs -l /dev/mapper/system-home tune2fs 1.42.6 (21-Sep-2012) Filesystem volume name:   <none> Last mounted on:          /home Filesystem UUID:          55899b65-15af-437d-ac56-d323c702f305 Filesystem magic number:  0xEF53 Filesystem revision #:    1 (dynamic) Filesystem features:      has_journal ext_attr resize_inode dir_index filetype needs_recovery extent flex_bg sparse_super large_file huge_file uninit_bg dir_nlink extra_isize Filesystem flags:         signed_directory_hash  Default mount options:    user_xattr acl Filesystem state:         clean Errors behavior:          Continue Filesystem OS type:       Linux Inode count:              9830400 Block count:              39321600 Reserved block count:     1966080 Free blocks:              22958937 Free inodes:              2706313 First block:              0 Block size:               4096 Fragment size:            4096 Reserved GDT blocks:      1014 Blocks per group:         32768 Fragments per group:      32768 Inodes per group:         8192 Inode blocks per group:   512 Flex block group size:    16 Filesystem created:       Tue Jul  8 08:02:22 2014 Last mount time:          Sun Apr 24 22:33:00 2016 Last write time:          Thu Sep  8 09:18:01 2016 Mount count:              11 Maximum mount count:      10 Last checked:             Tue Jul  8 08:02:22 2014 Check interval:           0 (<none>) Lifetime writes:          349 GB Reserved blocks uid:      0 (user root) Reserved blocks gid:      0 (group root) First inode:              11 Inode size:           256 Required extra isize:     28 Desired extra isize:      28 Journal inode:            8 First orphan inode:       2759586 Default directory hash:   half_md4 Directory Hash Seed:      e4402d28-9b15-46e2-9521-f0e25dfb58d0 Journal backup:           inode blocks   Please let me know if more details are needed.

I have a filesystem that has lots of small files. Currently about 80% of inodes are used (I checked with df -i), however only 60% of disk space is used. How can I 'increase' the number of inodes? If it was just disk space, I know that I could just increase the size of the disk (this disk is on LVM). If I increase the size of the disk, will that make me have more inodes?  I'm willing to grow the filesystem this disk is on, if that'd help.


Today I saw a comic where one of the characters say:     What's that mean?     I am not a native English speaker but that sentence puzzled me.   I would personally use the verb to do here but instead there's a 's which I assume is the verb to be contracted.  The other option is that 's here is the verb to do contracted, but I'm not aware of this contraction to be possible.  Is the sentence correct in English? Or is it some "slang" language. The character is not supposed to speak slang or incorrect English at all, so that's why this sentence drew my attention.

In conversation sometimes I’ll say something like this:     What’s that do?   which uses “s” as a contraction for “does”.  Is this a “real” contraction, or is it incorrect usage of a contraction?


Without manipulating the actual date and time using the datetime module, is there any way to basically say:  # wait x amount of time  call_function()   Is there any way to replicate that without using datetime? If not, how would I do it using datetime?

I would like to know how to put a time delay in a Python script.


///EDIT/// The Question Is Not Asking What A Null Pointer Exception Is, Merely What Might Have Caused It In This Instance. As Such IS NOT A Duplicate Of The Post Linked.   Im trying to search the entire system for any mp3 or wav files. If I use the algorithm for a small tree such as the users desktop it works fine, but if I go for a larger tree such as the users home directory it throws a null pointer exception. Anyone know how I can get around this?  package audioTest;  import java.io.File;   public class Main {       public static void recListFile(File[] list){         for(File i : list ){             if(i.isDirectory()){                 recListFile(i.listFiles());             }             else{                 String filePath = i.toString();                 StringfileExt=filePath.substring(filePath.lastIndexOf(".")+1);                 if(fileExt.equals("wav") || fileExt.equals("mp3")){                     System.out.println(i.getName());                 }             }         }     }//end recListFile       public static void main(String[] args){          File dir = new File(System.getProperty("user.home"));         try {             recListFile(dir.listFiles());         } catch(NullPointerException n) {             // more general: catch(Error n)             // anything: catch(Throwable n)             System.out.println("Caught "+n);             n.printStackTrace();         }     } }   Here is the exception and stack trace   Exception in thread "main" java.lang.NullPointerException     at audioTest.Main.recListFile(Main.java:11)     at audioTest.Main.recListFile(Main.java:13)     at audioTest.Main.recListFile(Main.java:13)     at audioTest.Main.recListFile(Main.java:13)     at audioTest.Main.main(Main.java:30)

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?


What's the difference between a statistical pseudorandom number generator (PRNG) and a cryptographic-strength PRNG?  I've seen a lot of PRNGs that are proposed for statistical uses -- e.g., statistical simulation, games, that sort of thing.  These statistical PRNGs include schemes like linear congruential generators, linear feedback shift registers (LFSR), Mersenne twister, and .  I've also seen many proposals for cryptographic-strength PRNGs: PRNGs designed for cryptographic uses.  These include constructions such as AES-CTR DRBG, HMAC_DRBG, ANSI X9.17, and .  What's the difference between these two kinds of PRNGs?  Is there any difference?  Can I take a PRNG that was designed for statistical use, and use it for cryptographic purposes?  Would that be safe?  If I find some statistical PRNG that looks nifty but wasn't designed specifically for cryptographic use, would it be reasonable to use it for cryptographic uses?  What if I start with a statistical PRNG and then tweak it a little bit -- would it be OK then?  This is intended as a general reference question that we can point others to, when they ask about specific instances of this sort situation.

What is the difference between CSPRNG and PRNG?   Is there performance differential between them? For example: We use PRNG for key generation which is very expensive and CSPRNG for IV/nonce in block ciphers which is fast?  What is the difference between the two types of RNGs?


I have an hp slate 21 running android jelly bean that needs something like ubuntu on it to make it useful.  I accept I need to root it and risk bricking it but it's not much use as it stands so not much lost I have some but not a lot of computer knowledge so need detailed help

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


I know how to add a command to the Unity Launcher, but don't know how to have automatically opened terminal for the command.  Especially needed when sudo command needs password or command result should be seen.

Will Unity allow making custom launcher icons from .desktop files or via menu editing system? (Right now the launcher doesn't give the option to "keep in launcher" on all programs.  For some programs I use, I have to make custom launchers or .desktop files.  For instance, daily blender builds are generally just folders with an executable.  In basic Gnome or KDE, I can make a new menu entry with the menu editing system. Then, I can also add it to Docky either from the menu or by dragging a .desktop file to it. Unity launcher doesn't support drag and drop, so thats not a bug or anything, but when I open a .desktop file, it has unpredictable results. Most time it will not have "keep in launcher". Sometime it will have a pinnable item without the .desktop's icon, and if I pin the item to the launcher, it will not call upon the program again after closing it. I've also gotten it to just work with a .desktop file for celtx.


I need to upgrade some specifics packages from sid on debian jessie stable with their dependencies.  By adding  the following repo :  deb http://ftp.fr.debian.org/debian/ sid main deb-src http://ftp.fr.debian.org/debian/ sid main deb http://ftp.fr.debian.org/debian/ sid main contrib non-free deb-src http://ftp.fr.debian.org/debian/ sid main contrib non-free   to my sources.list, all the existing packages will be upgraded and can damage my system.  How to install a specific package from "sid" on debian jessie "stable"  without breaking my existing system ?  Edit  How to set the pin-priority  to upgrade ? and how can it be used to downgrade a specific package when something went wrong ?

I want to install a single package (and its dependencies, but only to the extent those are not satisfiable in Wheezy) from Debian Jessie onto my Wheezy system, without upgrading "everything and the kitchen sink" to the Jessie versions. Specifically, I'd like to install , which is available packaged in Jessie but not in Wheezy.  Everything I've found indicates that I should add the Jessie repositories to my sources list, set pinning to keep everything at wheezy and only take the single package from jessie, and it'll pretty much just fall into place. However, it isn't falling into place for me. If I create /etc/apt.d/sources.list.d/jessie.list with the following content:  deb ftp://ftp.debian.org/debian/ jessie main deb-src ftp://ftp.debian.org/debian/ jessie main   and then create /etc/apt/preferences.d/jessie with:  Package: * Pin: release a=wheezy Pin-Priority: 1001  Package: kpcli Pin: release a=jessie Pin-Priority: 450   and run apt-get -u update followed by apt-get -u install kpcli/jessie, then I expect apt-get to pull in kpcli and maybe a small handful of other packages from Jessie, and leave the remainder of my installed system untouched. (My system is a fully up to date installation of Wheezy.) Alternatively, if I got the pin priority too low, I'd expect it to do nothing. Rather, on my system, apt-get wants to upgrade several hundred packages.  What, exactly, is needed to install just this one single package of a Jessie version while leaving the remainder of my Wheezy system untouched?  Note that in this particular case, the software is actually written in Perl so there's no compilation to binary or anything like that involved; however, there is a handful of Perl module dependencies. Hence, one possible alternative would be to install the .deb (downloaded manually) using something that only (1) allows specifying a single, local .deb archive that is to be installed, like dpkg -i, and (2) handles dependencies in an intelligent way, which plain dpkg -i doesn't. However, for all the searching I've done on several occasions and failed to come up with a simple-to-follow guide for how to do this, a generic solution (one that works for binary, compiled packages as well) would be great.


I had turned 13 last month and entered the exact date I was born in at Roblox, but Roblox still didn't lift the age restrictions. Is this an error, bug or what? I was looking forward for this restriction lift but it doesn't seem to happen somehow.

When I turn 13 years old, will some of my Roblox account restrictions unlock automatically?


I am trying to match content on variable c to variable s and selecting the match but all I get is a black bracket or it repeats variable c.  var s = "flowing through a lava occasionally"; var c = "occasionally, sleep, and, oops"; var re = /(?:^|\W)c(\w+)(?!\w)/g, match, matches = []; while (match = re.exec(s)) {   matches.push(match[3]); } console.log(matches);

I would like to create a String.replaceAll() method in JavaScript and I'm thinking that using a regex would be most terse way to do it.  However, I can't figure out how to pass a variable in to a regex.  I can do this already which will replace all the instances of "B" with "A".  "ABABAB".replace(/B/g, "A");   But I want to do something like this:  String.prototype.replaceAll = function(replaceThis, withThis) {     this.replace(/replaceThis/g, withThis); };   But obviously this will only replace the text "replaceThis"...so how do I pass this variable in to my regex string?


I have a PHP website that takes file uploads, and I want to be able to do certain actions based on the file type. But I don't want to trust what type of file the browser says it is, and would rather read the file's header to determine it. Do any libraries exist for this in PHP? Or would this be something I need to write from scratch?

Ok, so I have an index.php file which has to process many different file types.  how do I guess the filetype based on the REQUEST_URI.  If I request http://site/image.jpg, and all requests redirect through index.php, which looks like this  <?php    include('/www/site'.$_SERVER['REQUEST_URI']); ?>   How would I make that work correctly?  Should I test based on the extension of the file requested, or is there a way to get the filetype?


Because she always talked rubbish about omens, deaths, the Grim, etc, which never happened. Even Professor McGonagall told students not to pay attention to her nonsense. I also wonder why Dumbledore kept her as a teacher.

Throughout the Harry Potter series, Professor Trelawney makes many different prophecies and predictions. Although most of them are implied to be nonsense, often enough they still get fulfilled. Which ones have come true? Which ones have been proven false? Which ones are still possible?  How many of Trelawney's prophecies have come true?  I'm not asking if Divination in Harry Potter is real, or what it is. I am asking for a finite list of which of Trelawney's prophecies came true, and which ones didn't.


How would you make Skype video calls on Ubuntu tablet m10? And how does it work?

How do I install Skype or Viber on Ubuntu Touch?  My platform: Google Nexus 4, Ubuntu Touch stable


This is your typical elastic collision problem except the balls have finite radius.  To be clear:   two billiard balls in the plane each with radius $\sigma$ move at constant velocities $v_1, v_2$ starting at positions $x_1, x_2$   What is the criterion for there to be any collision at all?  When does it happen? And at what angle to they collide?  I need it to write a computer simulation of the .

I'm building a physics simulator for a graphics course, and so far I have it implementing gravitational and Coulomb forces. I want to add collisions next, but I'm not exactly sure how to go about doing it.   A quick summary of how this is working so far is: All objects are spheres of a set radius, mass and charge. The mass's and charges of the spheres are treated as point charge/mass for the calculation. Every step in time (about 1/50th of a second) the forces acting on each object are calculated in a nice big nested for loop that figures out the coloumb and gravitational force between 2 objects, for every set of 2 objects, and then they are summed together. I use this net force to determine the acceleration, and the rest is fairly obvious from there.   What I want to add in is collisions. I can deteremine pretty easily if a collision is happening (if the distance between them <= radius of one + radius of other), what I am not so certain of is how I should add in the collision force (and would need to do it component wise). I want elastic collisions, though for now I'd just be happy with getting conservation of momentum  The information I have easily available are: the velocity of each object (and I mean velocity, speed and direction), the position of each object, the mass/charge (charge obviously not needed here) and the Net force calculated so far for each object for the next step in time. I dont need exact formulas (would prefer if they arent exact), just need a nudge in the right direction.


I noticed that when I login to my bank account online I have to type my password twice in order to see my full checking account number. Then I was writing a check and noticed the entire account number is at the bottom for anyone to see. That seemed like a security issue to me. Am I being too paranoid or would it be wise to avoid using personal checks because of the account number being visible to anyone? Also, is it possible to request personal checks with the account number partially hidden?

I'm managing the utility of the house and I'm sharing with another person. He asks me to provide my bank account number, so that he can transfer his money to my account when paying the utility.    I wonder if it is safe to give out my bank account number?   For example, if I'm correct, many online payments just need the account number to draw money out of it. Is giving out the bank account number safer than handing a check to another person, since there is also the account number printed on the check?


Today I have setup 3 servers (4 including the server sending the SSH commands) with a public SSH key so I can automate some scripts  It works on the 2 first systems but not on the third.. SSH still prompt for the password when sending a SSH command  Generate SSH public/private key on local server  root@local # ssh-keygen -t rsa file > /var/.ssh_keys/id_rsa passphrase > (empty) root@local # ln -s /var/.ssh_keys/id_rsa /root/.ssh/id_rsa   Append key to remote hosts from local server  root@local # cat /var/.ssh_keys/id_rsa.pub | ssh root@host 'path="/var/.ssh_remote_key" && mkdir -p $path && cat >> $path/authorized_keys && ln -s $path/authorized_keys /root/.ssh/authorized_keys'   Local server  # uname -a Linux 3.16.0-4-amd64 #1 SMP Debian 3.16.7-ckt11-1+deb8u3 (2015-08-04) x86_64 GNU/Linux  # sshd -V OpenSSH_6.7p1 Debian-5, OpenSSL 1.0.1k 8 Jan 2015   Remote servers (working)  # uname -a Linux 3.16.0-4-amd64 #1 SMP Debian 3.16.39-1+deb8u2 (2017-03-07) x86_64 GNU/Linux  # sshd -V OpenSSH_6.7p1 Debian-5+deb8u3, OpenSSL 1.0.1t  3 May 2016   Remote server (still prompting for password)  # uname -a Linux 3.16.0-4-amd64 #1 SMP Debian 3.16.7-ckt25-2 (2016-04-08) x86_64 GNU/Linux  # sshd -V OpenSSH_6.7p1 Debian-5+deb8u2, OpenSSL 1.0.1k 8 Jan 2015  CHMOD /root/.ssh = 0700 CHMOD /root/.ssh/authorized_keys = 0644

I'm working from the URL I found here:    My ssh client is Ubuntu 64 bit 11.10 desktop and my server is Centos 6.2 64 bit. I have followed the directions. I still get a password prompt on ssh.  I'm not sure what to do next.


I try to log in on the normal log in screen and the screen goes black for a second and then kicks me back to the log in screen. I can log in with a guest session just fine, however. I've tried this with unity, cinnamon and good old fashion gnome, and the same thing happens with all three. I've looked through the log files, but none of them seem to have anything related to this problem. Right now, cinnamon and unity have been completely removed from the system.

My Ubuntu is stuck in a login loop when trying to enter my desktop. When I login, the screen gets black and soon after that the login screen comes back.   I've read that the problem might be caused by an error depending on the graphics, here's my graphics card: ATI Radeon 7670M


I have an upstart script that needs to run on reboot or shutdown, but it needs to access the network to post an http requests and wait for the replies, I tried  start on starting rc   and  start on starting (rc and net-device-up IFACE=eth0)   but no luck.

Since Ubuntu relies on upstart for some time now, I would like to use an upstart job to gracefully shutdown certain applications on system shutdown or reboot. It is essential that the system's shutdown or reboot is stalled until these applications are shut down.  The applications will be started manually on occasion, and on system shutdown should automatically be ended by a script (which I already have). Since the applications can't be ended reliably without (nearly all) other services running, ending the applications has to be done before the rest of the shutdown begins.  I think I can solve this by an upstart job which will be triggered on shutdown, but I am unsure which events I should use in which manner. So far, I have read the following (partly contradicting) statements:   There is no general shutdown event in upstart Use a stanza like start on starting shutdown in the job definition Use a stanza like start on runlevel [06S] in the job definition Use a stanza like start on starting runlevel [06S] in the job definition Use a stanza like start on stopping runlevel [!06S] in the job definition   From these recommendations, the following questions arise:   Is there or is there not a general shutdown event in Ubuntu's upstart? What is the recommended way to implement a "shutdown hook"? When are the events runlevel [x] triggered; is this when having entered the runlevel or when entering the runlevel? Can we use something like start on starting runlevel [x] or start on stopping runlevel [x]? What would be the best solution for my problem?   Thank you very much


$\{E_\alpha\}_{\alpha\in A}\ ,\ E_\alpha\subset E\subset\mathbb{R}$ where $A$ is an index set (may be uncountable)  is a condition for the axiom of choice in my lecture notes, along with $E_\alpha\cap E_\beta=\emptyset$ if $\alpha\ne\beta$  Why can't we simply write $\{E_\alpha\}_{\alpha\in A}\ ,\ E_\alpha\subset\mathbb{R}$ instead? Cause for any collection of $E_\alpha$'s their union contains them all and is a subset of $\mathbb{R}$  Just for context, our version of the axiom of choice concludes by saying that $\exists V$ that contains one and only one element from each $E_\alpha$

I have noticed that the family of non-empty sets referred to in statements of the Axiom of Choice is sometimes required to be mutually disjoint, and sometimes not. Why is that?


I am an undergraduate student at a Chinese university. Recently I asked for recommendation letters from two professors at my university, one Chinese and the other American, in order to apply for a summer program at a US institution. I have taken courses from both of these professors and performed quite well.   Upon hearing my request, the Chinese professor asked me to first write the recommendation letter for myself and then send it to him so that he can modify and sign it. The foreign professor, on the other hand, wrote the whole letter all by himself. I was later told by my classmates that it is the "common practice" for many professors in China to ask the student to write the recommendation letter for himself and then sign it.  Now my questions are: (1) Is the same thing a "common practice" in western universities? (2) Is it ethical for professors to transfer the load of writing the recommendation letters to students themselves? (3) I feel extremely uneasy when trying to write something that is supposed to praise myself. Is there any method for overcoming this uneasiness?  I would sincerely appreciate any help in answering my questions. Thanks!

If a student needs a reference letter for graduate admissions or that sort of thing, some profs will ask the student to write a reference letter for themself before sending it off to the prof for minor edits and finalization. This seems to be a somewhat common practice given that some graduate schools ask for several letters of recommendation even when it is not reasonable for the student to have developed deep connections with that many professors, and that most professors are just too busy to write quality letters for all the students that ask them to.  Is it acceptable to write most of the reference letter and have the prof make minor edits? Do academic institutions frown upon this practice? Would it be considered an academic offense if a student wrote a reference letter for themselves and had a prof sign it?


Please help me, im begginer here, mastahh notice me

Any ideas what's causing those chunks of geometric artifacts?  Argh.


I have recently found that my MC world does not auto-save (Don't answer on how to do that), so I have to /save-all every 5 minutes or so.  However, I have created a timer hooked up to a /save-all command block. Note that all repeaters are set to max delay.    Basically, what happens is, there is a redstone signal passing through the repeaters. When it reaches the end, it hits out a command block and loops around back to the starting which goes through the timer again.  I have timed this as 2:24.  Is there a much efficient design to the timer or any part of the structure? Is there also a way to increase the time without changing a major part of it?  Please don't suggest any latchology as I am terrible at it.

The only things I've found so far are a cart method (which ceased working in 1.6), a dispenser method (utilizing the decay on dropped items, but this requires occasional feeding), and a binary counter (which won't work for a single input but rather a fluctuating one).  I want to have a circuit that when I apply an input signal, the output signal doesn't change for 2 to 5 minutes.  When the input turns off, I again want a 2 to 5 minute delay.  I could accomplish this with (roughly) 240 to 600 redstone repeaters, but this is far in excess of being useful.  The only method I can think of, but would require a XOR gate (on the button-input and final output) to start and stop a clock attached to a binary counter.  While I can make room for a device of this size, I was hoping for something simpler.


Can someone please explain the bounty system?  I answered a question that featured a 50 rep bounty that no one else answered and I received nothing,   The other day  that featured a 500 rep bounty and got 3 upvotes. Before the bounty ended someone posted another answer and also got 3 upvotes. He got 250 points when the bounty ended but I didn't.   Why is that? and if there is no automatic split system that provides half of the bounty isn't that going to make some people to abuse it?

It's possible to offer and award bounties of reputation on questions.   What is a bounty? How can I find questions that have a bounty attached? How do I start a bounty? When can I start a bounty? Why is the system requiring me to choose a bounty amount that's higher than the minimum? Can I use Markdown formatting in the bounty remarks? Can I edit the remark? How long is the bounty period? How do I award a bounty? Can I award a bounty to my own answer? Can I award a bounty to an old answer? If I offer a bounty on someone else's question, can I award the bounty to their answer? After awarding the bounty, can I remove it or move it to another answer at a later time? What happens if there's no answer after the bounty period? What happens if I feel my question is still unanswered? What is automatic awarding? Are bounty awards exempt from the 200 points/day reputation limit? How does Community Wiki mode affect bounties? How does user deletion or post dissociation affect bounties? Can I award a bounty to an answer from a deleted user or one where the author was dissociated? Can I offer a second bounty after the first one has expired? Can I raise my bounty? What happens if a bounty question is closed or deleted? Why can't I vote to close or migrate a bounty question? What happens if I delete my account while I have an active bounty? Do I keep an awarded bounty when I delete my answer? What happens if a question where I awarded a bounty later gets deleted or migrated? Can I cancel my bounty? Can I affect / divide / share part of my bounty to two (or more) users? How many outstanding bounties can a single user have?      See also:  in the Help Center


In my code I'm getting milliseconds using   // elaspsed time in milliseconds     public long getElapsedTime() {         if (running) {             return System.currentTimeMillis() - startTime;         }         return stopTime - startTime;     }   As long is a whole number Where as I want to get the milliseconds in 00.0000 format  However I've tried this so far  return ((System.currentTimeMillis() - startTime) / 1000f);   but I am not getting to particular format

How do I format a number in Java? What are the "Best Practices"? Will I need to round a number before I format it?  32.302342342342343 => 32.30 .7323 => 0.73  etc.


I think this might have something to do with the fact that Windows 10 is still new and there has yet to be an update in Ubuntu to accommodate the following issue. Nevertheless, I think everyone should be aware of this so we can hopefully find a solution for it. Here we go!  I had Windows 7 and Ubuntu 14.04 dual boot just fine and was able to access my Windows partition (for music, pictures, etc) without any problems. However, upon doing the free upgrade to Windows 10, I had to re-install Linux on the remaining partition (no big deal). But now, the following happens. I can only access the Windows 10 partition if I first boot up Windows 10 and then "Restart" into Linux. Even if I shut down Ubuntu and go back into it, I'll still have access to the partition because the last function I performed in Windows 10 was "Restart." If I go back into Windows 10 and click "Shut Down" and then power back up into Linux, that's when I get the mounting error stating "Unable to access 'Windows 10'"  If you guys have any insight on how to fix this issue or if you believe that Ubuntu has to release an update to correct the problem, please respond either way! Thanks! :)

Whenever I boot Ubuntu, I get a message that it cannot mount my windows partition, and I can choose to either wait, skip or manually mount.  When I try to enter my Windows partition through Nautilus I get a message saying that this partition is hibernated and that I need to enter the file system and properly close it, something I have done with no problem so I don't know why this happens.    Here's my partition table, if any more data is needed please let me know.     Device Boot      Start         End      Blocks   Id  System /dev/sda1            2048    20000767     9999360   83  Linux /dev/sda2        20002814   478001151   228999169    5  Extended /dev/sda3   *   478001152   622532607    72265728    7  HPFS/NTFS/exFAT /dev/sda4       622532608   625141759     1304576   82  Linux swap / Solaris /dev/sda5        20002816   478001151   228999168   83  Linux


I am trying to end a loop when in two different instances: if it is empty and if the objects inside are null. However, when the program executes the second if-statement, I get nullPointerException, what am I doing wrong? (The statements are within a for loop but there is nothing in between them)              if(ER.isEmpty()){                 System.out.println(ER.size());                 break;             }             if(ER.get(0).equals(null)){                 System.out.println(ER.get(0));                 break;             }

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?


There is no any drive with my iMac and I know apple doesn't have program that could play Blu-ray until now, so can anyone give me some ideas about how can I make my iMac play Blu-ray disc movies?

I'd like to buy a Macbook Pro 15 inch instead of a Dell, and I know I can send video to the HDMI TV using the Moshi adapter.  My MacBook doesn't have a drive for Blu Ray discs. Is there a way to solve this?  I kind of want the navigation of chapters and extra features in a Blu Ray disc, so if using makemkv and a Sony external Blu Ray drive to make the Blu Ray disc into an .mkv file, that's not so preferred.  (Is one possible way to use the Sony external BD drive (about $180), and use bootcamp to boot up Windows 7 instead?  Although this method is not so preferred because it needs to boot up only Windows)


I am thinging how to format the table fit the frame size nicely in LaTeX.  I can recall that \tiny/... is not the optimum option here.  Code which output in Fig. 1   \documentclass{beamer} \usepackage[english]{babel} \usepackage{tabularx} \usetheme{Berkeley}  \logo{ %% llx lly urx ury \includegraphics[trim=8cm 2cm 11cm 2cm,clip, height=\headheight, width=\headheight]{example-image} } %\usepackage{hyperref} % Not needed! \begin{document} % https://tex.stackexchange.com/a/384801/13173 \section{1. skills} \begin{frame} \frametitle{Lorem}  % Maybe this one TODO but not \tiny https://tex.stackexchange.com/a/208763/13173 \begin{table}[] \centering %\caption*{Test} \begin{tabularx}{\textwidth}{|l|l|l|l|l|l|l|l|l|} %\begin{tabularx}{\textwidth}{|x|x|x|x|x|x|x|x|x|} \hline Avain lorem & V2 & V1 & V0 & START lorem & P1 & P2 & P3 & Kriittinen lorem \\ \hline  &  &  &  &  &  &  &  & \\ \hline \end{tabularx} \end{table}  \begin{Form} \begin{enumerate} \item \ChoiceMenu[name=football,radio,default=-0]{Do you play football?}{Much (2)=2,Little (1)=1,Not at all (0)=0} \item \ChoiceMenu[name=ice-hockey,radio,default=-0]{Do you play ice-hockey?}{Much (2)=2,Little (1)=1,Not at all (0)=0} \end{enumerate} \end{Form} \end{frame}  \end{document}   Output in Fig. 1    Fig. 1 Output    Proposal tabular format there but I think adjustbox is the worst what you can do   \begin{adjustbox}{max width=\textwidth,center} \begin{table}[hpt] \centering     \begin{tabular}{|l|l|l|l|l|l|l|l|l|}     \hline     Avain lorem & V2 & V1 & V0 & START lorem & P1 & P2 & P3 & Kriittinen lorem \\ \hline      &  &  &  &  &  &  & & \\ \hline     \end{tabular} \end{table} \end{adjustbox}   Output in Fig. 2    OS: Debian 9 TeXLive: 2017

I have a table that I want to insert on a page, but at least one (perhaps both) of the following conditions are met:   The table is too wide to fit within the text block or page. That is, I'm exceeding some horizontal restriction. The table is too tall to fit within the text block or page. That is, I'm exceeding some vertical restriction.   What are my options to make this table fit? If it doesn't fit, regardless of my attempts, what other options exist?


If I graduated from a university (named X for example) in 2014 and my average (or GPA) was the highest among all students who graduated that year from the same major (let's call it Y). So I want to say in my CV that my rank was the first. How to say that in a proffesional way?  What I'm currently using:     Graduated from X with a B.Sc degree in Y with an average of 90% (class rank: 1)

I have a question about how to write my ranking in a class in my CV. I mean, after graduation from the university for my BSc degree, my ranking due to overall GPA among the class of 30 students was 2. The class and the students in which we started our BSc degree education and graduated after 8 or 9 semesters. I want to high light this ranking in my CV in the section of honors and awards. How should I mention this?


I have to scrape a Website. I using phantomjs for this job. So there is a problem. I have to select form dropdown and then scrape the next page. I Don't know how to select a dropdown using Javascript. So AnyOne Can help me out. E.g We can click of any link using $('Selector').trigger('click'); Thank you for you time.

I have a drop-down list with known values. What I'm trying to do is set the drop down list to a particular value that I know exists using jQuery.  Using regular JavaScript, I would do something like:  ddl = document.getElementById("ID of element goes here"); ddl.value = 2; // 2 being the value I want to set it too.   However, I need to do this with jQuery, because I'm using a CSS class for my selector (stupid  client ids...).  Here are a few things I've tried:  $("._statusDDL").val(2); // Doesn't find 2 as a value. $("._statusDDL").children("option").val(2) // Also failed.      How can I do it with jQuery?     Update  So as it turns out, I had it right the first time with:  $("._statusDDL").val(2);   When I put an alert just above it works fine, but when I remove the alert and let it run at full speed, I get the error     Could not set the selected property. Invalid Index   I'm not sure if it's a bug with jQuery or Internet Explorer 6 (I'm guessing Internet Explorer 6), but it's terribly annoying.


Objects look amazing in the material preview mode, but not in the render preview (and also when rendered). I have attached two screen shots of a metal sphere in both viewports. Can anyone tell me what is wrong?

I'm trying to make a test render of my model. But everytime I render it the render looks completely different from the viewport. The viewport is in render mode so it should look something like that, but this doesn't come even close.   I'm using cycles renderer. And my world note is just the standard one so nothing installed there.  There are 2 sun's in the scene both set to 0.5.  I've tried different hdris but they all have the exact same outcome. I've pressed alt+h to see if there was anything hiddden in my scene that blocked the background and nothing shows up so I don't think that's the problem. I've also copied it to a new Blend file to see if there was anything wrong with the file itself but it also happens there so it must be something in my settings I guess. But I just can't find out which one    this is how it looks in the viewport render.    And this is how it looks when I render it.  I really don't know how to fix this so I hope someone can help me here


I'm trying to change the value of static variable that I passed to Klasa.method() function and sadly return value is ignored. package com.company;  public class Klasa {     public static int metoda(int x){         x += 2;         return x;     }  }  public class Main {     public static int i = 10;      public static void main(String... args) {         System.out.println(Main.i);         Klasa.metoda(i);         System.out.println(Klasa.metoda(i));         System.out.println(i);     } }

I always thought Java uses pass-by-reference. However, I've seen a couple of blog posts (for example, ) that claim that it isn't (the blog post says that Java uses pass-by-value). I don't think I understand the distinction they're making. What is the explanation?


Sometimes when I make a typo in the terminal and accidentally tell Bash to interpret /, I get the output bash: /: Is a directory. Now I believe this output has to deal with the root directory or something of that sort. But what I don't understand is that when I enter increasing amounts of forward-slashes it continues to output the same thing... Examples //// --> bash: ////: Is a directory //////// --> bash: ////////: Is a directory

I mistakenly typed cd // instead of cd /. To my surprise, current directory showed up as //.   What is that directory? Why does it exist?  apple@snipped $ pwd /home/apple apple@snipped $ cd / apple@snipped $ pwd / apple@snipped $ cd // apple@snipped $ pwd // apple@snipped $ cd /// apple@snipped $ pwd /


I have a laptop that came preinstalled with Windows 8 OEM.  I upgraded to Windows 10 when the free upgrade was available.   I want to die a clean install of the OS to remove all of the bloat ware.  My understanding was that you can do this and be legally licensed because of the original OEM license.    Will this still work for me if I install Windows 10 since it originally came installed with Windows 8?

I have a Windows machine (laptop) that needs fixing. The current installation is really badly broken (e.g. the taskbar is unresponsive, but the Explorer windows work, booting takes literally half an hour) and when I try to access the settings app and click on the tile to access the reset settings it instantly crashes. The same happens in Safe Mode.  I have created a USB install medium using the tool offered by Windows on my own Windows desktop machine. I've ensured that both the laptop and the USB tool have the same version of Windows (Home, 64-bit, NL). When I want to reinstall Windows on the laptop with this stick I am asked to enter a serial number which I obviously don't have. I don't want to try and see if I can phone activate it, because if it fails the install is gone.  I need to reinstall this Windows machine from a USB stick. There are a few problems I can't find an immediate solution for on the .   If I use a tool such as  to extract the serial number, will this work? If the above does not work, how can I reinstall this Windows machine?


I'm not sure if this feature is present on the Android app.

I haven't been able to find my favorite questions in the official Stack Exchange Android app.  Looking at my accounts page gives nothing on them.


I am struggling to figure out why the initialization of a multidimensional array in java is not working properly when I try to insert elements in the array one by one. My code is shown below:  public char[][] board; public Board() {       for (int i = 0; i < ROWS; i++) {           for (int j = 0; j < COLUMNS; j++) {               board[i][j] = ' ';           }       }   }   I tried to initialize the board array in setting it to "new char[6][7]" but that did not work. ROWS = 6 and COLUMNS = 7. Any help to figure out why this is giving such an error would be greatly appreciated. Thank you!

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 trying to overscan a tracked shot basically: I've shot some green screen footage, but the studio was not large enough to get the camera sufficiently far enough away from the talent for the shots we need, so I've got to extend/zoom-out the shot using overscan.  So I'm comping my 4k plate on to a 6k or 8k blank background, then tracking the shot, using Syntheyes with an un-distort/re-distort workflow, and outputting a Blender scene for the CG. All good so far, but obviously a pain to work in 6k or 8k regardless.  So I need to render a 6k or 8k image in blender, but 1k or 2k of the border around the shot is all totally redundant. So how can I 'render region' with the region accurately centred, and define the width and height of the region in pixels? So I'm not wasting time rendering a load of pixels which will be thrown away in the composite anyway.  Cheers Mark

I know I can set the render border with Ctrl+B and dragging a box.  But is there  a way I can exactly specify the border dimensions?


Please Note That the Question is Written as Intended Please do not edit my question so that it becomes a duplicate of another question, then flag it as a duplicate. I specifically stated that I am not asking for what is correct at least twice in this post. My question is specifically about the source of that information not the interpretation of the ruling. The Question Questions have been asked in this regards before, but never have I seen actual sources quoted on it.  This is not a question of what is correct. I am looking for a source that is official / authoritative (or from Sage Advice.) In the players handbook it states.   If the Attack involves other damage dice, such as from the rogue's Sneak Attack feature, you roll those dice twice as well. (PHB 196) Some attacks cause special effects in addition to or instead of damage (PHB 194)   The Attack Involves ... The question that has come up is what "the attack involves" means.   I have seen multiple interpretations of what "the attack involves means" and can see most interpretations having valid points.  Seeing as all of the differences hinge on the DM's interpretation of what "the attack involves" means I cannot use the above quote as a sole basis for discussion. Examples that I have encountered;  Paladin's Divine smite. Most argue that it is part of the attack and a Paladin gets to choose what level of spell slot he uses on divine smite after he sees that he gets to double the damage dice.  Some say that it is not involved in the attack and the smite is an a separate ability.  Other smites Most claim same as above, some claim it is a separate spell, and that it is a different instance of damage that Triggers on a hit and is not part of the attack itself. (see also hex and hunter's mark)  Poisoned weapons This one is more evenly split in my experience. Half say it is part of the attack since it triggers on a hit and should have its dice doubled. Others say it is a saving throw effect and so it does not have its effect doubled.  Attacks that trigger saving throws Several monsters have attacks that when they hit trigger saving throws against affects and do additional damage.  Like poisoned weapons above, some argue that it is all part of the same attack so, based on the second quote above, all of the dice should be doubled.  Others say that the damage effect is behind a saving throw and should not be considered "part of the attack".   Some have quoted the below trying to interpret it the way that most benefits them.  Each weapon, Spell, and harmful monster ability specifies the damage it deals... Magic weapons, special abilities, and other factors can grant a bonus to damage. ((PHB 196))  Some have used the above quote claiming that any and all effects that damage a creature that have any association with an attack roll have their damage dice doubled including the Area Effect portion of the Ice knife spell. (Their argument was full of holes but I decided to include it here to have more examples.) Just to be clear, I am not asking for interpretations of these examples. Each of these questions boils down to an interpretation of what is "involved in the attack" for the purpose of Critical hits. What makes for a good answer? what I am looking for is any Wizards of the Coast associated material that can be used to more clearly define what is and is not "part of the attack."

I'm a bit confused on how extra damage works for critical hits. Let's take the following example: A thief with sneak attack rolls a crit. I'm under the impression he rolls double his normal attack damage dice AND double his Sneak Attack damage dice. Is this accurate? Another example, I finished DM-ing my first campaign recently. The Giant Spider enemy monster has an melee attack that causes a constitution saving throw. If the player fails, the enemy rolls an additional 2D8 of damage. In this situation, if there was a critical hit, and the player failed their saving throw, would I also roll double dice on the additional damage? Or is that considered a separate attack?


I recall a sci-fi story (probably 1950's) situated on a world where the rotational speed was so high that relativistic effects were involved near the equator... the further away you were, the weaker the effect. individuals' names were longer away from the equator, because you had more time to express things. and, there was an on-planet war. i recall the main character having a name like "Hadolarison" near the pole. Can anybody clue me the title/author?

Trying to remember a short story (most likely from the sixties).  It starts with a soldier at the front line fighting an unknown enemy on the other side of the front line.  He then gets withdrawn and you realise that time is passing slower the further he moves from the front. He then spends years in peace away from the front, before being sent back to the front where only a short time (hours or days perhaps) have passed.      I seem to remember their was an inference that they were actually fighting against themselves, with their attacks coming back at themselves, which was perhaps the entire cause of the war, and an interesting critique on war.  I can't remember if this all this was stated explicitly, or just left for the reader to infer.


I am aware that it is possible to sort primarily by one field and secondarily by another field. For example:   $ echo -e "1 5\n1 4\n8 2\n1 9" | sort -k 1,1n -k 2,2n 1 4 1 5 1 9 8 2 $    However, am I correct that sort always keeps the lines intact, e.g. it is not possible to sort in a way that output would be following:  1 2 1 4 1 5 8 9   If this is not possible with sort, then what would be the correct tool for this?

$ sort -t $'\t' -k 1rn,1 -k 2,2rn -k 3f,4 listaprezzi  2050        900           bananas     5 1905        700           grapes      17 250         4000          oranges     10 230         9200          figs        4 220         5000          lemons      10 200         8000          pears       8   I want to sort 1st column of listaprezzi numerically in reverse (option rn), 2nd also rn, and third alphabetically (f). What is the correct command?  I've tried many ways but having no success.


I have two series of measurements values, first series is X and second is Y. I need to model Y as a function of X, where I know the method that was used to measure X is two times better then the method used for measure Y in terms of error variance.  I red about regression with error term in the independent variable, but I'm not sure what to do when there is also error term in the dependent variable and they are different.  Which technique/tools/constraints should I use for this sort of case?


I try to solve this the number of permutation in $S_{n}$ for $n\geq 4$ which are product of two disjoint $2$-cycles is $\frac{n(n-1)(n-2)(n-3)}{8}$. So after putting $n=5$ and $n=4$ I get different answer. Am I right ? Please help how to solve this. Thanks.

Let $l_{n}$ denote the number of those permutations $f$ on the set $A=\{1,2,....,n\}$ such that $f$ is the product of exactly two disjoint cycles. Show that $l_{5}=50.$    I tried a lot but reached nowhere around the answer. Any help will be appreciated. Thank you.


The three axioms that a measure function $m$ need satisfy are as follows. Let the word "measure" mean the value returned by this measure function, $m$ defined on a set in $\mathbb{R^n}$.   The measure of an interval $I$ is its length: $m(I)= l(I)$; The measure is translation invariant: $m(E+y) = m(E)$; The measure is countably additive over countable disjoint union of sets: $$m(\bigcup_{k=1}^\infty E_k)=\sum_{k=1}^{\infty} m(E_k)$$.   My questions are: Why cannot a set function be defined that satisfy all the above? What is the geometry or structure of $\mathbb{R^n}$ that prevents this from happening?  Considering $\mathbb{R^n}$ is complete, totally ordered, it seems like a space that is not pathological at all, yet it harbors this problem when comes to measure. Could someone explain why? Thank you.  Also, even though existence of a non-measurable set can be shown, can one be actually constructed?

What Is the reason behind the fact that $\Bbb R$ is not a complete measure space? Is it only due to the cardinality of  $\Bbb R$? Or other structures on  $\Bbb R$ also play a role? Can one make every subset of  $\Bbb R$ trivially measurable by assigning them to a number of a complete ordered field of the cardinality $\aleph_2$ ?


In its latest update today, Version 34.0.1847.116 m (April 9, 2014), Google Chrome removed the full URL from the address bar. This is super super annoying to developers who want to be able to see the path and parameters. Instead, Chrome only displays the domain, presumably to make some lame URL hacking exploits () impossible to pull off.    I know the URL is visible if I press Ctrl+L, but that's inconvenient. How can the old style full URL be brought back in the address bar / omnibox?

Something broke in my chrome install and now my current url is outside to the left of my omnibox:    I can even click it as a button and it brings me to that page, also it will always stay blank, even when typing in it.  Is there a way to reset the layout?


In my application i have been using retrofit for my webservice calls. It is not working fine. This is the error that caused when my application started     04-16 07:41:26.162 5860-5860/com.pance.taugaksih E/AndroidRuntime: FATAL EXCEPTION: main                                                                      java.lang.NullPointerException                                                                          at com.pance.taugaksih.activity.SplashscreenActivity$1.success(SplashscreenActivity.java:54)                                                                          at com.pance.taugaksih.activity.SplashscreenActivity$1.success(SplashscreenActivity.java:42)                                                                          at retrofit.CallbackRunnable$1.run(CallbackRunnable.java:45)                                                                          at android.os.Handler.handleCallback(Handler.java:725)                                                                          at android.os.Handler.dispatchMessage(Handler.java:92)                                                                          at android.os.Looper.loop(Looper.java:137)                                                                          at android.app.ActivityThread.main(ActivityThread.java:5041)                                                                          at java.lang.reflect.Method.invokeNative(Native Method)                                                                          at java.lang.reflect.Method.invoke(Method.java:511)                                                                          at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:793)                                                                          at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:560)                                                                          at dalvik.system.NativeStart.main(Native Method)   This is my code that callled retrofit with response NullpointerExeption   RESTClient.get().getPost(new Callback<ResponsePost>() {         @Override         public void failure(RetrofitError error) {             // TODO Auto-generated method stub             progress.dismiss();             Toast.makeText(getApplicationContext(), "AKSES KE SERVER GAGAL" + error.getMessage(), Toast.LENGTH_LONG).show();             finish();         }          @Override         public void success(ResponsePost post, Response response) {             // TODO Auto-generated method stub             if (post.getPost().size() > 0) {                 PostController chb = new PostController(myContext);                 chb.open();                 chb.deleteData();                 for (int y = 0; y < post.getPost().size(); y++) {                     PostModel tmpHasil = post.getPost().get(y);                     chb.insertPost(tmpHasil);                 }                 chb.close();                  Intent sendIntent = new Intent(myContext,PostActivity.class);                 startActivity(sendIntent);                 finish();             } else {                 Toast.makeText(getApplicationContext(), "DATA SEDANG TIDAK TERSEDIA", Toast.LENGTH_LONG).show();             }             progress.dismiss();         }     });   And this is code my RESTClient class  public class RESTClient { private static APIPost REST_CLIENT; private static String URL_TAUGAKSIH = "http://10.108.109.30/taugaksih_slim";  static {      setupRestClient(); }  private RESTClient() {}  public static APIPost get() {     if(REST_CLIENT==null){         setupRestClient();     }       return REST_CLIENT; }  private static void setupRestClient() {     RestAdapter builder = new RestAdapter.Builder().setEndpoint(URL_TAUGAKSIH).build();     REST_CLIENT = builder.create(APIPost.class); }   }


This  asks why isn't the Force used to snap a neck instead of choking. It is harder to snap a neck than to hold someone, so it kinda makes sense that it's not used often.  However, snapping a neck is a very ineffective way of killing if we have a ranged attack that can't be covered. Why not use the Force to pop a vein inside the person's brain? Just scramble a part of the brain and the person is gone. Not much strength is needed, the kill is instant (so you can't really prepare for it).  Why not just cause a stroke to an enemy?

If I can apply enough force to my enemy's neck to choke off his air supply, that same amount of force can be applied to their carotid arteries and render them unconscious instantly. A vastly lesser force could explode a blood vessel in their brain. Why is telekinesis not an instagib weapon in Star Wars?


I am trying to get the image id (which is at the end of the src link, right before file type) from this html but for some reason the regex I've written isn't working. Accessing document object in not an option in this case which is why i need regex for it. Any help would be appreciated thats what I have so far but its failing at sizes check const imgRegX = /
]*>\s*<img alt="?" sizes= "?"/g; Here is how the string looks:

I don't really understand regular expressions.  Can you explain them to me in an easy-to-follow manner?  If there are any online tools or books, could you also link to them?


I used to have a different PC, with Ubuntu on it. That PC broke, so I wanted Ubuntu back, but not fully on my laptop. So, I installed Virtualbox, followed all steps. But at boot, I get   The regular VB boot-up.  The purple Ubuntu screen w/ a man at the     bottom next to a keyboard A black screen w/ a blinking cursor Another purple screen with text saying: Ubuntu 14.04, and small dots     under it After about a minute, some text will show saying:     I can't figure out what to do. I've been to many links, also this (which was most suggested):  But the steps aren't clear. I can't get TO the OS, I can only see this at boot-up.  Thanks in advance.  Edit: I found that if I leave it, it eventually gets into the OS. Any steps from there?

I am trying to boot Ubuntu 13.04 in VirtualBox, but every time I boot, I get an error that says:  SMBus base address uninitialized - upgrade BIOS or use force_addr=0xaddr   This happens right after I start the virtual machine, and the operating system does not even start properly. I see the error, then the screen just goes black and gives me a blinking cursor. The solutions I have found online tell me to open up a terminal only after the OS boots correctly. Sadly, I cannot even get to that stage, so I can't use that solution.  Help?  By the way, I am VERY new to Virtual Box and creating virtual machines, so excuse me if I'm not familiar with some of the terminology. Another thing, if it helps, is that I'm running Windows 7 as my host OS.


I have recently read in book 'Theory Of Everything' that rate of expansion of the universe is changing 5%-10% per 1000 million years, I would like to know how such calculation has been made.   Edit: I want to know the principle and theory of finding the distance between galaxies and rate of expansion of the universe and not just formulae.

How does the  change with the age of the universe?  This question was posted recently, and I had almost finished writing an answer when the question was deleted. Since it's a shame to waste the effort here's the answer anyway.  Maybe this can be one of the canonical answers .


Im trying to get them to not overlap, but be snapped together. the center of the one i move snaps to the vertex of the idle one.

The following image is my failed attempt to make a sword handle's surface meet the blade's bottom. How can I snap the blade's bottom to the handle?


How do you find the vector of length 2 in ℝ2 making an angle of 30∘ with the x-axis?

How do you find a vector in the form  when only the angle and magnitude are given?  Here is an example where an angle of 80 degrees is given along with a magnitude of 3.


Last night I made candy apples for the second time. The first time they were perfect. Last night I made them at 10 pm and let them sit out over night. This morning they were hard but still sticky.  The only difference with the first batch is the sugar I used, this time it was super fine. The humidity in my house was at 60%. Was it the sugar I used?

When I candy-coat apples and let them sit out, the candy coating becomes sticky. I live in the Southern U.S., so humidity is usually pretty high, but other people in my area make them as well.


given two groups:$$a_{n+1}=\frac{a_n+b_n}2, b_{n+1}=\frac{2a_n*b_n}{a_n+b_n}, a_1=x,b_1=y$$ We need to prove that both series converge to the same limit, and show what the limit is, without knowledge of which value is greater at the start.  I managed to prove that for every $n$, $a_n*b_n=x*y$, which would mean that $b_n=\frac{xy}{a_n}$. I also know that the two series are bounded by x and y, but I still cannot figure out how to carry on from there. Any advice?

I need to show the following:     Starting with a point $S=(a,b)$ of the plane with $a>b>0$, we generate a sequence of points $(x_n,y_n)$ according to the rule: $$x_0=a, y_0=b, x_{n+1}=\frac{x_n+y_n}{2}, y_{n+1}=\frac{2x_ny_n}{x_n+y_n}.$$ Prove that $\lim x_n=\lim y_n=\sqrt{ab}$.   I can show that $x_ny_n=ab$ and $x_n>y_n$ for all $n$, but I am having trouble proving $\lim x_n=\lim y_n=\sqrt{ab}$. Suggestions?


I have a piece of code in jQuery/.NET MVC that looks like this:   $('form').submit(function (event) {                 event.preventDefault();                 event.stopPropagation(); // only neccessary if something above is listening to the (default-)event too                 if ($(this).valid()) {                     $('#confirmLoader').show();                     $('.btnregister').hide();                     var formdata = new FormData($(this).get(0));                     $.ajax({                         url: this.action,                         type: this.method,                         data: formdata,                         processData: false,                         contentType: false,                         success: function (result) {                             if (result.statusCode == 700) {                                 //  var loginWrapper = result.View.find(".loginWrapper").innerHTML;                                  //  var sas = $($.parseHTML(result.View)).find(".loginWrapper").prevObject[45].innerHTML;                                    // $($.parseHTML(result.View)).find(".loginbody").html()                                 //                                 //console.log($($.parseHTML(result.View)).find(".loginbody").html());                                 $(".loginbody").html($($.parseHTML(result.View)).find(".loginbody").html());                                //$("body").html(result.View);                                 //                                 // console.log(result.View);                                 return false;                             }                             else if (result.statusCode == 200) {                                 window.location.href = result.url;                             }                          }                     });                 }                 return false;             });   So the basic purpose of this method is to post the data and log in the user onto the system.  In the case of the when the server responds with error code 700 => I render the entire page in .net MVC action and return it as a result to the user and should be displayed;  So for example, if I entered xy mail and wrong password, the message is displayed the first time, but the second time I get the entire page rendered, without even getting the javascript code to execute.  I have to note two things:  $("body").html(result.View);    Like this, the response always works when the status code is 700 and it always displays the message properly.  However, I don't want to replace the entire DOM of the user, only the portion where the login form is, and display the error message.  Thats why I tried this:  $(".loginbody").html($($.parseHTML(result.View)).find(".loginbody").html());   With this solution it only works first time... Second time it renders me the entire page, and I can see the page being refreshed...  Why is this happening with solution #2?  P.S. this is the code that is returned in  background:  ModelState.AddModelError("WrongUsernamePassword", "Wrong username or password!");  return Json(new { statusCode = 700, View = this.RenderView("Login", model) });   Why doesn't 2nd method works?  Can someone help me out?

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.


so I am making a palindrome checker that ignores any white space or special characters. Below is part of my function. What it does is it takes a c string as an argument, then I create another c string in order to remove the whitespaces and special character from the orignal. When I output the second c string, it still will have the whitespaces or special characters. Could some explain why it is doing that? Thanks  bool isPalindrome(char *line) {    //variables    bool palindrome = true;    int length = strlen(line);    int count = 0;      //copy line to line2 with no spaces and no punctuation    char *line2 = new char[length + 1];    int count2 = 0;     for(int i = 0; i < length; i++)    {       if(line[i] != ' ' && ispunct(line[i]) == false)       {          line2[count2] = line[i];          count2 ++;       }    }    for(int i = 0; i < count2; i++)        cout << line[i];    line2[length] = '\0';

What is the preferred way to remove spaces from a string in C++? I could loop through all the characters and build a new string, but is there a better way?


I am implementing a php site that allows users to upload their pictures, I created the uploads directory at the same level as root but now how can I access those images in html.  I tried following  <img src="../../uploads/<?=$filename?>">

Here is the directory structure  /domain.com  /public_html   /functions   /image   /mobile   /www   the /domain.com/public_html/www folder has a file index.php the default web directory is /user/public_html/www in the index file is an include that includes the functions with include"../functions/function.inc" this works without problem when I want to link to a picture in the image folder I don't get any results for example      Does anybody has any idea why the link to the image does not work and how to link correctly to the image file ?  I tried <img src="<?php echo $_SERVER['PHP_SELF']; ?>../image/graphic/logo.gif" alt="alt text"/>  but that gives me the same result when I build a link around the image to get to the properties I get this as path  the path should be   when I try to browse directly to this url  I get an 404 file not found error because the default web directory is /domain.com/public_html/www I tried  to get to the image folder but that does not help neither.  Anybody any ideas or is it impossible to html link to graphical files outside the default web directory ?  thanks for reading this far  Thanks for the answers so far. I will try to solve my problem with one of the recommended solutions and report my working solution back here. I wanted to have the image folder at the same level as the www and mobile folder because some of the images used for the pc (www) version and the mobile version are the same. Of course it is easier to just get an image folder in the www and in the mobile folder and I think that is what I am going to do.  thank you everybody for the advice. The main reason why I am not going to work with a script is that a script will be a difficult solution to an easy problem and also because I don't really see how you can wrap your image in a css class and how to provide alt text for an image.


My understanding was that when 20.04-1 came along that I would see a prompt on my multiple 18.04 machines that would offer to allow me to do an upgrade. I do know how to force it from the command line but was wondering when I might see the prompt message from the Software Updater GUI screen ? The "Software & Updates" screen does have: Notify me of a new Ubuntu version: For long-term support versions but that doesn't result in the expected prompt and something to click on to do the upgrade. Will this be forthcoming?

I want to use do-release-upgrade to upgrade from 18.04 to 20.04, but I can't do that do-release-upgrade Checking for a new Ubuntu release There is no development version of an LTS available.  It seems that  is used, and it still points to 18.04. Do you know when (or how?) can I upgrade to 20.04?


I have decided to switch to Windows. I would like to completely remove ubuntu, and all the other files on my computer. How do I do this? I basically want to wipe my computer clean.

I have absolutely no experience with Linux, and I desperately need to get my computer back up and running again with Windows.  How do I remove Ubuntu and reinstall Windows?    Editor's note: many of the answers are about removing Ubuntu from dual-boot but keeping Windows (which is a bit complicated), while other answers are about removing Ubuntu from single-boot (which is easy: basically just format the disk while installing Windows). The question as written is ambiguous between dual-boot or single-boot.


I installed current MacTeX version (20150613) and then updated TeXShop to most recent version, Version 3.61.  In the BibTeX engine setting, I wrote biber, and in the document I additionally have:  %!TEX TS-program = xelatex %!TEX encoding = UTF-8 Unicode %!BIB TS-program = biber  \usepackage[backend=biber]{biblatex} \addbibresource{bibliography.bib}   I'm typesetting with XeLaTeX through Typeset ⌘T command multiple times and references are not resolved. It seems that biber is not invoked. If I go to terminal and manually invoke biber document.bcf, my references get resolved in the next typesetting pass.  What am I missing?

I am trying to use BibTeX on my Mac to produce some simple citation references.   I copied some example code from online tutorials into a .tex file and a .bib file. The first LaTeX run on TeXShop gives me a PDF without any references. An .aux file is generated and valid. But I am failing at the next step. Normally BibTeX should run on the recently produced .aux file and generate an .bbl file which LaTeX uses in his second compile run, right? It doesn't. There is no .bbl file produced and I am getting no messages about it. It appears that the step "BibTeX runs on the .aux file to generate an .bbl file" never starts.  I am using TeXShop on Mac OS. Any ideas? How do I even start the BibTeX thing on Mac OS? When I'm working on Windows in TeXnicCenter it does this step by itself.


I'm taking a time difference between two LocalDateTime values. I'm using the Duration for that. And now I want to convert it into hh:mm:ss format as a String value. I've been checking how this can be done but still no luck. Any guidance will be appreciated.    LocalDateTime startTime = some value  LocalDateTime endTime = some value  Duration totalWaitingDuration = Duration.between(endTime, startTime);  String waitingTime = String.valueOf(totalWaitingDuration.toHours());    In this, I'm getting the time difference only in hours. How can i get it in hh:mm:ss format?

I'd like to format a duration in seconds using a pattern like H:MM:SS. The current utilities in java are designed to format a time but not a duration.


Title sums it up, but I'll break it down into two parts.  Part 1: Will console commands disable achievements in Steam? Part 2: If achievements are disabled will it be forever or just for game session?

I'm wondering in case I get stuck in an area that I'm unable to get out of or if I clip into a wall and I suddenly can't move. I've had to disable clipping to get out of certain areas in Skyrim before but I want to make sure that things like my achievements and stuff won't shut out on my playthrough.  If I enable something, spawn an item that didn't spawn for me, or just basically use the console command to fix any bugs, what will happen achievement and game-wise?


Given $(x+y+z)^{15}$ find the coefficient of $x^2y^{10}z^3$   Weak in this chapter. Don't know how to proceed. Please help  Sorry for the typo made before

What is the coefficient of the term $a^i b^j c^k$  in the expansion of   $(a+b+c)^n$ ?   Given solution:     Before collecting like terms, each term in the expansion is a product   of $n$ factors each  of which is $a, b,$ or $c$.  Those terms which   have exactly i a’s, j b’s and k c’s can be combined into   the single term $a^i b^j c^k$ and the number of such terms will be   equal to the number of n letter strings containing i a’s, j b’s and k   c’s, which by the Mississippi rule is $\frac{n!}{(i!\times j! \times  k!)}$.   I understand that this problem is actually about the derivation of the coefficient of the multinomial theorem,but I am not sure about the combinatoric reasoning,what I mean is that I understand the analogy problem but what I couldn't is how the analogy holds here,Could anybody explain this to me?


I tried the various solutions offered in the question of which mine appears to be a duplicate. Some of them did not actually convert the time, one of them did convert the time but the year was wrong and it did not replace the existing value in the file, it added a new column to the output. The answer I accepted below met my needs perfectly.  Sorry if this is a duplicate, I searched extensively and didn't find questions matching my situation. I use Linux frequently but my "programming" skills are limited to simple shell scripts.   I have a csv file with a column of date/time stamps written in the epoch (i.e. Unix) format. Please see below example. I would like to convert and replace the Unix time with the ISO 8601 format.   Example of existing output:   foo, 1439856000000000000, foo, foo foo, 1439856360000000000, foo, foo foo, 1439856720000000000, foo, foo foo, 1439857080000000000, foo, foo   Example of Desired output:  foo, YYYY-MM-DD HH:MM:SS.nnnnnnnnn, foo, foo foo, YYYY-MM-DD HH:MM:SS.nnnnnnnnn, foo, foo foo, YYYY-MM-DD HH:MM:SS.nnnnnnnnn, foo, foo foo, YYYY-MM-DD HH:MM:SS.nnnnnnnnn, foo, foo


I needed to create a list of lists in Python, so I typed the following: my_list = [[1] * 4] * 3  The list looked like this: [[1, 1, 1, 1], [1, 1, 1, 1], [1, 1, 1, 1]]    Then I changed one of the innermost values: my_list[0][0] = 5  Now my list looks like this: [[5, 1, 1, 1], [5, 1, 1, 1], [5, 1, 1, 1]]    which is not what I wanted or expected. Can someone please explain what's going on, and how to get around it?


I had 2 os on my computer Windows and Ubuntu, I wanted to remove windows and did this with OS uninstaller,but all the space from windows left there and I cant move that space to my ubuntu using Gparted The ext3 is deleted Windows and i need to move that space to ubuntu(ext4). Thanks for Help.

Previously, I have installed Windows 7 on my 320 GB laptop with three partitions 173, 84 and 63 GB each. The 63 GB partition was where the Windows was installed. The rest were for file containers.  Now I changed my OS to Ubuntu 12.04 LTS. I installed Ubuntu by replacing the entire Windows 7 on the 63 GB partition. The rest of the partitions remain as an NTFS Windows partition and I can still access them both (the 173 and 84 GB partitions).  Now I want to change the two partitions of Windows into an Ubuntu format partitions plus most importantly, I want to extend the 63 GB partition to more than a 100 GB because at the moment I am running out of disk space. Whenever I try to install any application, especially using wine, it always complains for a shortage of disk space.  How do I do the extending activity before I entirely format my laptop again and lose all the important files on my partitions?


I know you can take vials and fill them to be vials of water, and add feathers to arrow shafts, but is there anything faster and more effective?

I have 99 magic, 99 fletching, 91 firemaking and 83 woodcutting, and no money.  How can I make money using the skills I listed above?


I am studying the Linux command line. But the book which I'm reading says that su -l(-) username is starting a new shell session and loading the environment of the user I want to change to, but su doesn't.  When I was root user, I entered the command su testuser, so I am testuser. But after that, I entered echo "$USER", and it says testuser. It means that it loads testuser's environment, doesn't it? Is there something wrong?  And what does "starts a new shell session" mean exactly? Does shell have a mechanism like login, logout?

What is the difference between the following commands:  su sudo -s sudo -i sudo bash   I know for su I need to know the root password, and for sudo I have to be in the sudoers file, but once executed what is difference?  I know there is a difference between su and sudo -s because my home directory is /root after I execute su, but my home directory is still /home/myname after sudo -s. But I suspect this is just a symptom of an underlying difference that I'm missing.


The two biggest computer companies in the world use opposite scrolling directions!  When you switch from Windows to Apple, you'll notice that Apple has its scrolling reversed. But maybe it's Windows who has its scrolling reversed..  Which makes me wonder:  what scrolling direction is the right direction and should it be different than a the swiping direction of a touch pad?  Things to consider:    What's natural? In what direction would a first time user scroll to go down the page?  Should a mouse have the same scrolling direction as a touchpad?

I am wondering whether there are any usability studies out there regarding natural vs. reverse (traditional) scrolling. I tried to google the matter a bit and it seems natural scrolling took off with some Mac OS version - but remains controversial even in the Mac community.  I generally find using a trackpad clumsy - mainly with regards to scrolling. I have, however, only really used reverse scrolling. My issues are only compounded by natural scrolling, but I am wondering whether it might end up being a better experience if I invested the time needed to get used to it.  I guess Apple must have had some intelligent reason for imposing a standard that needs so much getting used to on the part of their users. IS there any evidence that natural scrolling is a switch worth making?


I want an example of a sequence that satisfies $\mid x(n) - x(n-1)\mid \to 0$ but not Cauchy ? I tried to find such sequence  $x(n)=1/2,1/3,1/2,1/3,1/4,1/2,1/3,1/4,1/5,,,,$ it's not Cauchy since it is not converges (has infinitely limit points) and the difference between any successive terms goes to zero .. I asked my doctor but he said the difference is constant (not zero)since the sub-sequences here are constants  So can any one gives me a hint for this problem :)? thanks in advance ^^

Give an example of a sequence $(x_n)$ of real numbers, where $\displaystyle\lim_{n\to+\infty}|x_n-x_{n+1}|=0$, but $(x_n)$ is not a Cauchy sequence


I've extracted strings I'm interested in from another file and now have a list like this:  StringA StringB StringA StringA StringB StringC StringB   How can I extract the number of occurrences each string has using common command-line tools?  I would like to end up with a list like this:  StringA 3 StringB 3 StringC 1

I had a command which would work through a text file, count all the occurrences of the words and print it out like this:  user@box $˜ magic-command-i-forgot | with grep | and awk | sort ./textfile.txt 66: the 54: and 32: I 16: unix 12: bash 5:  internet 3:  sh 1: GNU/Linux   So it does not search line-by-line, but word by word, and it does it for all the words, not just for 1 word. I'd found it somewhere on the internets a long time ago, but I cannot find or remember it..


I've installed wine with: sudo apt-get install wine  I've downloaded OfficeSetup.exe from the official Microsoft website (student license) and then I typed in the terminal:  sudo su ... wine "OfficeSetup.exe"  I see the Office logo with the loading animation, and after a few seconds it appears to me an error message saying that the installation can't proceed with these possible motivations:  internet connection down, no space available on disk,  but any of these are true in my situation. No other replies in the terminal, no other warnings from wine, anything. What could I do?

How can I get playonlinux to install Microsoft Office 2016. The options from the install menu only go up to 2013.   Is there a more recent version of PlayOnLinux (or indeed Wine) I can download to enable installation of MS Office 2016?  The steps I take are:   open PlayOnLinux  click Install Click Office returns a list of several software packages including MS Office 2007, 2010 and 2013 (but alas not 2016)


I'm using a skin modifier to create a straight line between two vertices, to simulate a cord being stretched between two moveable points.  I'm following the suggestion in this response  (minus using soft bodies, since my cord doesn't need to have curves).  The cord shows up in editing and even in Rendered Mode for viewport shading, but it's not in my final renders. I have 'Use modifier for render' set to true for all four modifiers for this line (the anchor hook, the moveable hook, the skin, and the subsurf) but I'm not sure what else I need to set to make this show up in the actual render.      (I'm also new to blender so I'm guessing I'm missing something obvious, but I haven't found any other questions on this)

This is meant to solve this problem once and for all. What is every reason an object isn't showing up in a render or viewport in when using the cycles render engine?


When people say about wave-like nature of a photon, what do they mean:   Pressure-like wavefront - it moves as a sphere (or a bulge on a surface) and then if we measure pressure at one single point (after the front moved further) - it will raise and fall "drawing" a wave. Something like an arrow - it moves in the space, but it also has internal vibrations. Different points of it have different curvature. Something that just moves along one axis, but also moves up-and-down along the other axis. Something else?   Option #1 means the photon itself doesn't "know" anything about waves - the wave is the impact that was left after it. Option #2 and #3 mean that crests/troughs are intrinsic to the photon.

We know a sound wave is a disturbance that moves through a medium when particles of the medium set neighboring particles in motion. And using the pressure variations we can plot a  pressure/time graph which looks like a 'wave'in the drawing sense.  What do we mean when we say light is a wave and particles? using the above system, can we  say that light is the disturbance that moves through a medium of photons( forgive me that makes no sense). When we draw a light 'wave', what does it mean? a photon goes up and down?  Please keep the answer as 'not complicated math' as possible.


I have to prove this result:      If $P$ be the power set, and $B$ and $C$ are two sets, then if $B \subseteq C$ prove that $P(B) \subseteq P(C)$.   Now, it seems obvious to me that since all the elements of B are in C, all possible combinations of the elements of C must include those that of B. But other than this straightforward argument, I'm at a loss to see what kind of proof can be given for statements like these.   Can anyone suggest something more "proper"?

Can someone please verify this?     Show that if $B \subseteq C$, then $\mathcal{P}(B) \subseteq \mathcal{P}(C)$   let $x \in \mathcal{P}(B)$.  Then, $x \subseteq B$  This implies that $$\forall a \in x, a \in B$$  This further implies that $$\forall a \in x, a \in C$$  Therefore, $$x \subseteq C$$  This implies that $$x \in \mathcal{P}(C)$$


Please can we get a filter or additional tab within the profile screen to show questions I have asked with no accepted answer.  Perhaps render the acceptance %age as a link to said questions.  In this way we could quickly see the sorts of questions that someone has been unable to accept answers to.

I think it's helpful if we can go to a page and view all our own questions that   Does not have an accepted answer, and/or Does not have an answer yet.   The reason I asked for them is because, I sometimes need to review through all the questions, and pick those that don't have proper answers so that I can perform further operations on them ( such as offering a bounty, or accept an existing answer).


My first attempt at using a stream and a lambda expression:   Stream<TableType> myTTStream = Arrays.stream( T[source] ); // T[source] is a 1D row from a 2D array     Optional<TableType> closest = myTTStream              .filter( tt -> !tt.visited ) // tt is each TableType object in the stream; select for unvisited             .sorted( (tt1, tt2) -> Integer.compare(tt1.dist, tt2.dist) ) // sort them by distance to an output stream             .findFirst() // get the first (lowest) distance (returns a possibly empty Optional describing the first element)             ;      return ( !closest.isPresent() || closest.get().dist == Integer.MAX_VALUE ) ? -1 : closest.get().dist; // have to get the value from the Optional   The code creates a stream from a row of the T[][] array, filters it for the boolean visited false, sorts the result, and returns the first (lowest-valued) item of the stream. It seems to work except when no items get through the filter, in which case findFirst() causes an error leading ultimately to a null pointer exception.   I don't understand this because findFirst() returns an Optional, which according to the docs, may be empty. So what's the problem? If it's due to the sorted() method being fed an empty stream, then why doesn't that line cause the error?   I'm pretty sure there are no null elements in the T array.   The stack trace (the code above is the body of the method "closestUnvisited"; line 238 is the ".findFirst()" call):   Exception in thread "main" java.lang.NullPointerException at GraphM.lambda$0(GraphM.java:236) at java.util.stream.ReferencePipeline$2$1.accept(ReferencePipeline.java:174) at java.util.Spliterators$ArraySpliterator.tryAdvance(Spliterators.java:958) at java.util.stream.ReferencePipeline.forEachWithCancel(ReferencePipeline.java:126) at java.util.stream.AbstractPipeline.copyIntoWithCancel(AbstractPipeline.java:498) at java.util.stream.AbstractPipeline.copyInto(AbstractPipeline.java:485) at java.util.stream.AbstractPipeline.wrapAndCopyInto(AbstractPipeline.java:471) at java.util.stream.FindOps$FindOp.evaluateSequential(FindOps.java:152) at java.util.stream.AbstractPipeline.evaluate(AbstractPipeline.java:234) at java.util.stream.ReferencePipeline.findFirst(ReferencePipeline.java:464) at GraphM.closestUnvisited(GraphM.java:238) at GraphM.findShortestPath(GraphM.java:167) at GraphM.main(GraphM.java:343)

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?


In    it is said:  "question eligible for bounty since Feb 16" but there is no link to start the bounty ...  Could someone explain what is going on there?  P.S. I just deleted my answer and yet there is no link to start the bounty ... So what is happening now?

I have 78 reputation and  is eligible for bounty 2 days ago. Yet I cannot offer a bounty on my question.    It appears that because I have an answer on my question, the system requires me to offer a minimum bounty of 100. But since my answer is already deleted, what can I do to offer a bounty on my question now?


I get that the mods do not want people to abuse the edit system just to rack up the edit counts, but stack overflow is primarily about code. Therefore we must be exact.  I recently came across a post with a missing parenthesis, other than that it was spot on. This may only take someone a few seconds/minutes to find if they copy paste, but why make it hard to correct this.  Maybe a better idea would be to allow edits that are within code tags to be less than 6 char.

, to correct a misspelled library enum in an answer. Since the edit was only one character, I also had to add a superfluous sentence to get over the character limit required to edit a post.  I've hit this problem before in other edits, always in code snippets. Since the edit limit exists to prevent trivial edits, and since there are many cases where one character code edits are not trivial (= to == etc), would it make sense to have a lower edit minimum inside code snippets?


I read this maybe 10-15 years ago.   Aliens have conquered earth. Possibly quite some time before the time then novel is set in. They have built their own cities. They conduct periodic athletic competitions for humans similar to the current olympics. The winners are take into the city to act as servants to the masters. The protagonist is part of a human resistance movement who is competing in the games. The plan is to infiltrate the city, gather intel and escape. He wins, get in, finally has to kill his master and escape down a waste disposal system which ends up outside the city.   Anybody knows which one I am talking about?

I remember reading a series when I was around 7th or 8th grade about aliens who had taken over Earth by putting metal caps on people when they were "entering adulthood" to control them (not direct control, but it would keep them from rebelling). There was a faction of people who able to escape and had fake caps and would save teens who were about to be capped.  The main protagonist was a teen boy who was a boxer (or training to be a boxer or something). The aliens would hold tournaments for the humans and whoever won would be "worthy" to serve as personal slaves to the aliens.     The protagonist won and was able to get inside to try and learn more about the aliens from the inside.


I'm writing a document that uses the degree symbol extensively. I know I can use 40$^\circ$ but it's cumbersome so I defined a command \degree for use in text mode. The problem is I can't add a space after using \degree.  How do I add a space after the degree symbol for the second line?  For example:  \newcommand{\degree}{$^\circ$}  Take bearing 40$^\circ$ North for 20 minutes  Take bearing 40\degree North for 20 minutes

I have a definition:  \newcommand{\arnold}{Arnold Schwarzenegger}   When I refer to it by:  \arnold is a   it is rendered as:   Arnold Schwarzeneggeris a    In order to have a space in front of "is" I would need to write  \arnold\ is a   Is there some other shorter way?


The following problem I'm working on is for one of my favorite past-times: game development.  Problem: We're in 3D space. I'm trying to determine if a line between two vectors in said space is passing through a circle; the latter of which consists of: center vector, radius, yaw & pitch. In order to determine that, my aim is to convert the circle to a plane which can either be infinite or just have the diameter of the circle for all it's sides. Should the line between the two vectors in fact pass through that plane, I am left with the simple task of determining whether that intersection point is within the radius of the circle, in which case I can return either true or false.  What's already working: I have my circles set up and the general framework is there. The circles are appearing/rendered in the 3D space exactly as specified, great!  What was already tried: Copied some github gist codes and tried to make them work for my purposes. I kinda worked, sometimes at least. Unfortunately due to the nature of how the code was written, I had no idea what it was doing and just scrapped all of that. Researched the topic a lot, too. But due to me not really understanding the language people speak when talking about line/plane intersections, I could have read the answer without recognizing it as such.  Question: I'm stuck at line intersections. No idea where to go and how it works logically! So, where do I go from here and how can one comprehend all of this?  Note: I'm working with Java, but I'm not looking for spoon-fed code. It's a logical issue I'm trying to get past. If explained well enough, I will make the code work with trial and error!

I was reading something about: “Intersection of a line with a plane”. But I don’t fully understand how to calculate it on their way.  The goal is to calculate where the plane and the line will “cross”. These items are given:   The eye is in position: O(0,0,-10)   A point of a 3D-object is P(10,20,30) The screen has the equation z=0   I have a questions about how they calculate this:    This part is clear. That is the location form the eye (vector representation).   They specify the location of the plane, there is nothing strange here (vector representation).   Now they calculate what part of the line will cross, how did they calculate this? How did they know a = 1/4? And b = 10/4?  This is everything that was given.


I know that, when moving a file, you need to git add the "new" file and git rm the "old" file so git can see it as renamed rather than removed... but how can you fix a (pushed) commit that didn't do this properly?  I made a commit directly in Visual Studio and I wasn't paying enough attention - it renamed multiple files, and they now show as if the old files were removed and new ones were added, rather than the old files being renamed. I only realised this after having pushed multiple commits on top. Is there a way to fix it?  (And bonus question - why didn't Visual Studio handle this properly and how could I make it work next time, without having to use separate terminal commands?)

I've moved a file manually and then I've modified it. According to Git, it is a new file and a removed file. Is there any way to force Git into treating it as a file move?


I want to ask if there is this result $$\sum_{p\text{ are prime numbers}}\dfrac{1}{p^2}\approx 0.452224742...<\dfrac{1}{2}?$$ I sincerely thank you.

I am trying to prove $\sum_p p^{-2} < \frac{1}{2}$, where $p$ ranges over all primes. I think this should be doable by elementary methods but a proof evades me.   Questions already asked here (eg.  and ) deal with the exact value of the above sum, and so require some non-elementary math.


Just installed Ubuntu 12. on my new computer. When trying to download files I want to use Transmission but after I choose a file to download Transmission is not in the list of programs to run with (infact it's empty) and when I click "Choose a program" (or whatever it says in english") and find the folder Transmission there's no file or program to choose from (I also choose "show hidden files", the folders within the Transmission folder are empty exept for settings.json. When I go to the list of settings in Firefox, Transmission are not among these and I don't know how to add it. Please, help. Want to getting started downloadning again.

Every time I download a torrent file (.torrent), Firefox thinks I should open it with a text editor. How can I get it to open with Transmission? In Edit -> Preferences -> Applications, there's no setting for torrent files, and no apparent way to add a new filetype.


What is it called when object A is accelerating at rate B, but rate B is also accelerating at rate C. What is it called? How does it work? How can I apply it?

I know this may seem a weird question, but it always bothers me. My physics book (Resnick,Halliday,Walker), and also various sites never say anything beyond acceleration.   But when a moving body is being acted by a variable force , its acceleration will definitely change: it will either increase or decrease. Then there will be rate of change of acceleration with respect to time. So, why don't books mention this? What is the cause for not measuring $\frac{d\vec{a}}{dt}$ ? If it exists, what is the use of it?