When I add phablet-team's PPA using  sudo add-apt-repository ppa:phablet-team/tools   I get:  Err:17 http://ppa.launchpad.net/webupd8team/atom/ubuntu disco Release 404  Not Found [IP: 91.189.95.83 80] Reading package lists... Done                        W: GPG error: https://packages.microsoft.com/repos/vscode stable InRelease: The following signatures couldn't be verified because the public key is not available: NO_PUBKEY EB3E94ADBE1229CF E: The repository 'https://packages.microsoft.com/repos/vscode stable InRelease' is not signed. N: Updating from such a repository can't be done securely, and is therefore disabled by default. N: See apt-secure(8) manpage for repository creation and user configuration details. E: The repository 'http://ppa.launchpad.net/mystic-mirage/pycharm/ubuntu disco Release' does not have a Release file. N: Updating from such a repository can't be done securely, and is therefore disabled by default. N: See apt-secure(8) manpage for repository creation and user configuration details. E: The repository 'http://ppa.launchpad.net/noobslab/apps/ubuntu disco Release' does not have a Release file. N: Updating from such a repository can't be done securely, and is therefore disabled by default. N: See apt-secure(8) manpage for repository creation and user configuration details. E: Failed to fetch http://repo.mysql.com/apt/ubuntu/dists/disco/InRelease  Clearsigned file isn't valid, got 'NOSPLIT' (does the network require authentication?) E: The repository 'http://repo.mysql.com/apt/ubuntu disco InRelease' is not signed. N: Updating from such a repository can't be done securely, and is therefore disabled by default. N: See apt-secure(8) manpage for repository creation and user configuration details.   what can I do??
When updating, I get the following error message:   W: The repository 'http://ppa.launchpad.net/mc3man/trusty-media/ubuntu xenial Release' does not have a Release file.   Here, I find another statement on this error:   This recommends removing certain PPAs; and, I'm not sure if I should do that since it might mean not getting the updates that I need.    Is this what I should do?
How to remove or hide the GRUB boot menu? Recently I decided to use only Ubuntu and there is no Windows in my laptop. When I turn on my laptop the GRUB menu is showing but I don't need to choose OS anymore.   How can I remove or hide this? And after removing this how could I access to recovery mode? I have two JSON objects with the same structure and I want to concat them together using Javascript. Is there an easy way to do this? How can I avoid name mangling in C++? I wrote a little bash script that made me stumble across the . I did not know about this problem before and I just dare on posting the --debug output I got from date when my script tried to calculate across this magic date (03:14:07 UTC on 19 January 2038).  date -d "20380119"  date: parsed number part: today/this/now date: input timezone: +01:00 (set from system default) date: warning: using midnight as starting time: 00:00:00 date: starting date/time: '(Y-M-D) 2038-01-19 00:00:00 TZ=+01:00' date: '(Y-M-D) 2038-01-19 00:00:00 TZ=+01:00' = 2147468400 epoch-seconds date: output timezone: +01:00 (set from system default) date: final: 2147468400.000000000 (epoch-seconds) date: final: (Y-M-D) 2038-01-18 23:00:00 (UTC0) date: final: (Y-M-D) 2038-01-19 00:00:00 (output timezone TZ=+01:00) Tue Jan 19 00:00:00 CET 2038   date -d "20380119 + 1 days"  date: parsed hybrid part: +1 day(s) date: input timezone: +01:00 (set from system default) date: warning: using midnight as starting time: 00:00:00 date: starting date/time: '(Y-M-D) 2038-01-19 00:00:00 TZ=+01:00' date: warning: when adding relative days, it is recommended to specify 12:00pm date: error: adding relative date resulted in an invalid date: '(Y-M-D) 2038-01-20 00:00:00 TZ=+01:00' date: invalid date '20380119 + 1 days'   date -d "20380120" --debug  date: parsed number part: today/this/now date: input timezone: +01:00 (set from system default) date: warning: using midnight as starting time: 00:00:00 date: error: invalid date/time value: date:     user provided time: '(Y-M-D) 2038-01-20 00:00:00 TZ=+01:00' date:        normalized time: '(Y-M-D) 2038-01-20 00:00:00 TZ=+01:00' date:  date:      possible reasons: date:        numeric values overflow; date:        missing timezone date: invalid date '20380120'   Is there any way to make GNU date calculate across this date? (on a LINUX 32 bit system)    Operating System: Debian GNU/Linux buster/sid             Kernel: Linux 4.12.0-2-686-pae       Architecture: x86 Generating hatched filling using Region functionality How to read such figures with % as "up (by) 120%" and "increased (by) 120%". Do they mean the same? filter the file type with the file upload control How to properly indent PHP/HTML mixed code? Is temperature a Lorentz invariant in relativity? When installing OpenBSD 5.1, I got the question:   Do you expect to run the X Windows System?   What change does the installer make to my system if I say "yes"? I know what X Windows is, but I don't know why the installer wants to know if I plan to use it. Does it enable/disable X somehow based on my answer? Placeholder for body off in Android app The placeholder for the body field (the word "Body") is strangely placed in the Android app, seems a bit too high:    Could reproduce using:   Samsung Galaxy 4a.  Android version 4.4.2  App version 1.0.54 Moto X (2013), Android 4.4.4 App version 1.0.60 How to get the current user in ASP.NET MVC How do I add the kernel PPA? \AtEveryBibitem{\clearfield{Title}} in beamer? In my beamer presentation, I want to cite the reference without title. So, I tried:  \documentclass{beamer} \usepackage[   backend=bibtex8,   defernumbers=true,   sorting=none,   firstinits=true,   uniquename=init,   uniquelist=false,   refsegment=section,   citestyle=numeric ]{biblatex} \addbibresource{mini.bib} \AtEveryBibitem{\clearfield{Title}} \begin{document} \section{Start} \begin{frame}   first cite\footfullcite{Julie2006}   %\printbibliography \end{frame} \section{2nd} \begin{frame}   Second cite\footfullcite{gyof} \end{frame} \end{document}   with the mini.bib :  @article{gyof,   Author={BLJ},   Title={Some Title},   Journal={joural1},   volume={15},   pages={1337},   Year={1985} } @article{Julie2006,   Author={JBS},   Title={Some Other Title},   Journal={journal2},   volume={74},   pages={144411},   Year={2006} }   with \AtEveryBibitem{\clearfield{Title}} I was expecting no title will be produced, but thats not the case:   Is there any incompatibility between clearfield and footfullcite? Or I am just missing something? Highlight whole TreeViewItem line in WPF jQuery: live() vs delegate() How to create a rounded cone combinatorics: sum of product of integer compositions We now that Fermat's last theorem is true so there are not positive integer solutions to $$x^n+y^n=z^n$$ for $n\in\mathbb{N}$ and $n&gt;2$.  But what about if $n\in\mathbb{R}$ or $n\in\mathbb{R}^+$? So earlier today I came across , and I am having some trouble understanding the solution. The question is as follows:     You throw a fair six-sided die until you get 6. What is the expected   number of throws (including the throw giving 6) conditioned on the event   that all throws gave even numbers?   Quoted from Jimmy Jin in "Elchanan Mossel’s dice problem"  In the paper it goes on to state why a common wrong answer is $3$. Then afterwards explains that this problem has the same answer to,   "What is the expected number of times you can roll only $2$’s or $4$’s until you roll any other number?"  I don't understand why this is the case. If the original problem is asking for specifically a $6$, shouldn't that limit many of the possible sequences?  I also attempted to solve the problem using another method, but got an answer different from both $3$ and the correct answer of $1.5$.  I saw that possible sequences could have been something like:  $$\{6\}$$ $$\{2,6\}, \{4,6\}$$ $$\{2,2,6\}, \{2,4,6\}, \{4,2,6\}, \{4,4,6\}$$ $$\vdots$$  To which I set up the following summation and solved using :  $$\text{Expected Value} =\sum_{n=1}^\infty n\left( {\frac{1}{6}} \right)^n 2^{n-1} = 0.375$$ Obviously this is different and probably incorrect, but I can't figure out where the error in the thought process is.  Any help on understanding this would be greatly appreciated.  A blog post discussing the problem can be found