Solving $p^2=2xq^2+2yq+1$
How to find solutions of linear Diophantine ax + by = c?
How to center window title text? Dual-boot boot menu does not show up after installing Ubuntu 15.10 alongside Windows 10 Is it acceptable to add a duplicate answer to several questions? how many terms will there be once you collect terms with equal monomials? What is the sum of all the coefficients? If you expand $(x_1+x_2+\cdots+x_k)^n$, how many terms will there be once you collect terms with equal monomials? What is the sum of all the coefficients?  I'm kind of lost here. This came up with other questions on the topic of binomial coefficients, and i have figured those out. I have spent almost an hour trying to figure where to start and haven't made any progress. Cannot start XAMPP on Ubuntu 11.10 I am a super newbie for Ubuntu and basically need Ubuntu for a Python package.  I would like to run a Python file in say e:/username/folder1/folder2/python.py. I tried every method online and the only reply is bash: cd./e: No such file or directory. I am not sure whether it is because of the bash windows or virtualenv.  When I use bash on Ubuntu on Windows, ls, it says VIRTUALENV_DIR. cd, it says /home/username. The cd .. etc changes the directory a little, but not another drive, nor the folder I would like it to find. Today is the release of Ubuntu 21.04 (Hirsute Hippo). And I can't update to this version. And also I selected ‘Notify me of a new Ubuntu version’ and changed it to ‘For any new version' on the Updates tab on Software &amp; Update, but it's still not working. In addition, in the terminal, I've written: sudo do-release-upgrade -c  And output was: Checking for a new Ubuntu release No new release found.  What should I do? Whenever I try to Get then Install any app from the App Store, I get this message:     We could not complete your purchase.  cancelled   I did some searching online, but barely found any useful hits. What is this about?! Do Dragonborn get tails/wings? The positive integer solutions for $2^a+3^b=5^c$ What are the positive integer solutions to  the equation     $$2^a + 3^b = 5^c$$    Of course $(1,\space 1, \space 1)$ is a solution. Does more reflective aluminum foil make a room cooler compared to less reflective foil? Aluminum foil is said to be not absorbing light at all. It reflects light. So, does it mean that a more shiny aluminum foil will reflect more light and thus make the room more cooler as compared to less shiny foil?  If yes, then where does unreflected light go in case of less shiny aluminum foil?  Does less shiny and more shiny actually make a difference? Why?  In order to keep whole room cool will it help if I stick the foil to the outside of wooden door (exposed to the sunlight) too? What permissions should a udev rule have for a USB device? 644? 755?  For example on Ubuntu I'm looking at this file: /etc/udev/rules.d/99-lpcscrypt.rules sorry fresh user. I installed about 9 days ago and had issues with Unity disappearing which took 5 days of headaches to fix. It never did fix, I reinstalled.   I set up Plex (media server) and while the server is running and can be accessed by external network devices, I can't add files. Plex says this is because of permissions. I have gone up and down the forums here and at Plex to get an answer. It seems everyone says   chmod -R 755 /media/My\ Book/Videos   will change permissions to allow the folder "Videos" on my external USB 2.0 NTFS 3TB Western Digital drive (which is mounted and accessible through the file manager) as well as every sub-directory and file contained therein to be accessible to user "Plex".  I have used file manager and as soon as you click to change permissions it changes right back. When I chmod with -c it tells me every file is changed (usually 600) to 755 as I commanded it to do. I did   ls -l   to verify and there is no change. (I also used ls -l to make sure I knew who the owner was and it is me (mvl1014). ls -al gives me the same info.)  I swear to god I tried to sudo it and after smashing my head against this keyboard for basically the entirety of my day, I tried it as root. I was scared shi-less but couldn't come up with anything else. sudo su to root and then chmod -R -c /media/My\ Book/Videos  Same result. -c told me every single file was changed and a check in Unity or in terminal confirmed not a darn thing changed.  Now it seems to me that even if that isn't the thing stopping Plex from working there is still a problem with this command not going through.  12.04LTS -- on gen 1 i7 (2.7 GHz I believe) with 6 GB ram   I've attempted to attach a screenshot but I'm told I need 10 reps to do so, which means I'm copy/pasting too.  Please excuse my obfuscation, but Lorem Ipsum seemed unnecessary. And I tried multiple ways to format this but it looks perfect every way and messed up each time in the preview below. (Ugh, I'm a mess.)  $ chmod -R -c 755 /media/My\ Book/Videos  .....  .....  .....  mode of `/media/My Book/Videos/xxxx/xxxx/xxxx.mkv' changed from 0600 (rw-------) to 0755 (rwxr-xr-x)    ls -al shows:  mvl1014@FX6800:/media/My Book/Videos$ ls -al   total 88  drwx------ 1 mvl1014 mvl1014     0 Aug 28 15:17 .   drwx------ 1 mvl1014 mvl1014 20480 Sep  3 14:29 ..  drwx------ 1 mvl1014 mvl1014  8192 Aug 28 15:18 xxxx drwx------ 1 mvl1014 mvl1014 49152 Aug 16 14:02 xxxx drwx------ 1 mvl1014 mvl1014  8192 Aug 27 21:36 xxxx drwx------ 1 mvl1014 mvl1014  4096 Jul 23 19:09 xxxx   I apologize if this has been asked. I looked through this place plus at all the suggested "Similar Questions". The closet thing I got to an answer , but running the provided code with my own UID didn't work either. Python 3 with QGIS on Mac? I want to make a generic class that accepts only serializable classes, can it be done with the where constraint?  The concept I'm looking for is this:  public class MyClass&lt;T&gt; where T : //[is serializable/has the serializable attribute] Is there a way to have a copy of any message sent from a Gmail account sent to another address?  I've got any messages coming to my address copied to another (see  for one solution, setting up filters is another), but I haven't yet found a way to have outbound messages automatically copied.  Is there a way? A sequence includes $a_p=\sqrt2$, $a_q=\sqrt3$, $a_r=\sqrt5$ for some $1\leq p<q<r$. Can these be terms of an arithmetic progression? harmonic? Does the Mordenkainen's Magnificent Mansion spell's mansion exist on a separate plane of existence? In particular: the  spell (PHB, p. 281) states:  [...] The creature can be anywhere on the same plane of existence as you. The spell ends if you or the target are no longer on the same plane. [...]  Can telepathy connect two characters, one inside the extradimensional dwelling created by the  spell and the other in the same plane as the portal to the magnificent mansion? What is the proper way to write the plural of a single letter? Or a word used as a word ('mention' usage)? (another apostrophe question) When writing (a blog post, script, etc..) what is the proper way to indicate two or more instances of a single letter? For instance, in Monty Python's Bookshop Sketch:     C: I wonder if you might have a copy of "Rarnaby Budge"?      P: No, as I say, we're right out of Edmund Wells!      C: No, not Edmund Wells - Charles Dikkens.      P: (pause - eagerly) Charles Dickens??      C: Yes.      P: (excitedly) You mean "Barnaby Rudge"!      C: No, "Rarnaby Budge" by Charles Dikkens.  That's Dikkens with two Ks, the      well-known Dutch author.      P: (slight pause) No, well we don't have "Rarnaby Budge" by Charles Dikkens      with two Ks, the well-known Dutch author, and perhaps to save time I      should add that we don't have "Karnaby Fudge" by Darles Chickens, or      "Farmer of Sludge" by Marles Pickens, or even "Stickwick Stapers" by Farles      Wickens with four M's and a silent Q!!!!!  Why don't you try W. H. Smith's?      C: Ah did, They sent me here.   I had always believed that plural never uses an apostrophe before the 's' (it's only used for possession), but I have rarely seen in written material the format "four Ms". (On a side note, whoever wrote  also used "two Ks".)  On a side note, and perhaps this should be a separate question, if a Compact Disc is a CD, then two Compact Discs would be two CDs right? (I see "CD's" written everywhere) Recommendations for Numerical Analysis texts?