I am unable to install synaptic on my system. I have tried the following but no luck.  sudo apt-get update sudo apt-get install synaptic   I get the output:  Reading package lists... Done  Building dependency tree Reading state information... Done  Package synaptic is not available, but is referred to by another package.  This may mean that the package is missing, has been obsoleted, or is only available from another source  E: Package 'synaptic' has no installation candidate   This is the error message I get when I run sudo apt update :  cccc@cccc:~$ sudo apt update [sudo] password for ccccc:  Ign:1 http://gb.archive.ubuntu.com/ubuntu artful InRelease Hit:2 http://archive.canonical.com/ubuntu artful InRelease Ign:3 http://gb.archive.ubuntu.com/ubuntu artful-updates InRelease Ign:4 http://gb.archive.ubuntu.com/ubuntu artful-backports InRelease Ign:5 http://gb.archive.ubuntu.com/ubuntu artful-security InRelease Err:6 http://gb.archive.ubuntu.com/ubuntu artful Release   404  Not Found [IP: 91.189.88.149 80] Err:7 http://gb.archive.ubuntu.com/ubuntu artful-updates Release   404  Not Found [IP: 91.189.88.149 80] Err:8 http://gb.archive.ubuntu.com/ubuntu artful-backports Release   404  Not Found [IP: 91.189.88.149 80] Err:9 http://gb.archive.ubuntu.com/ubuntu artful-security Release   404  Not Found [IP: 91.189.88.149 80] Reading package lists... Done                       E: The repository 'http://gb.archive.ubuntu.com/ubuntu artful 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://gb.archive.ubuntu.com/ubuntu artful-updates  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://gb.archive.ubuntu.com/ubuntu artful-  backports 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://gb.archive.ubuntu.com/ubuntu artful-security  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.   Does anyone know how to install it?
How do I get to the Universe Repository in supported versions of Ubuntu?
Checking via ArcPy if ArcMap is in edit session? Single word describing something "outside of oneself" Differential form is closed if the integral over a curve is rational number. The following problem comes from do Carmo's book Differential Forms and Applications, Chapter 2, Exercise 4:  Let $\omega$ be a differentiable 1-from defined on an open subset $U\subset \mathbb{R}^n$. Assume that for each closed differential curve $C$ in $C$, $\int_C \omega$ is a rational number. Prove that $\omega$ is closed.   Can anyone give some hints? My idea was that we could try to show the integral vanishes if the curve lies in $N_\epsilon (p)$ (i.e. a small neighborhood around $p$) for any $p$ in $U$ and use the Poincare Lemma, but failed. Find the general solution of $xy''-(1+x)y'+y=x^2$ knowing that the homogeneous equation has the following solution: $e^{ax}$, where $a$ is a parameter you have to find.  I have found that $a=1$ or $a=1/x$. I know that the Naruto movies are outside the timeline in the sense that they don't affect whatever happens after them. However, they must fall somewhere in the Naruto timeline — based on who are in the movies and how the characters look like, etc. For example, if Sasuke isn't in the movie, it should take place after he left. For each of the movies, approximately what timeframe (between episodes/arcs) are they set?  The movies:   Ninja Clash in the Land of Snow Legend of the Stone of Gelel Guardians of the Crescent Moon Kingdom Naruto Shippuden the Movie Bonds The Will of Fire The Lost Tower Blood Prison Road to Ninja The Last - Naruto the Movie Boruto: Naruto The Movie Some class features, monster traits, and feats allow you to take a −5 to your attack roll in order to gain a +10 to your damage roll. At first glance this looks really good, but when will it deal more damage than not using it on average?  For instance if you have a total attack bonus of +8 and you deal 1d12 damage. You have to roll a 7 to hit an AC of 15. If you take the −5 that makes it where you have to roll a 12. That's going to reduce your average damage by a lot. What keeps mass from turning into energy? Multiple Inheritance in C# Solving $\sin x\cos3x+\cos x\sin3x=\sqrt{3}/2$ in the interval $[0,2\pi]$ Solve the following trig equation: $$\sin(x)\cos(3x)+\cos(x)\sin(3x)=\frac{\sqrt{3}}{2}$$ in the interval $[0,2\pi]$.  Using trig identities, it is now at $$\sin(x+3x)=\sqrt{3}/2 \tag{1}$$ Next, it has become $$\sin(x+3x)=\sin 60^\circ \tag{2}$$ leading to $$\sin(x+3x)-\sin60^\circ=0 \tag{3}$$ From there, it is unclear what to do. How to re-enable tray icons for applications in Ubuntu? A movie about artificial intelligence gone rogue I have a professor at my university who uses content from an un-cited textbook that he has never referenced anywhere, including his green sheet (syllabus), as an additional resource. At least some slides he has used include parts of content that have been re-worded and others that are 100% the same. I noticed this by Googling for textbooks on the material we're studying in class and found that examples given in one that I found were exactly the same as what he has provided.  Would this technically be plagiarism? Should he be given the benefit of the doubt in this situation? Does anyone know of any good tools (I'm looking for IDEs) to write assembly on the Mac. Xcode is a little cumbersome to me.  Also, on the Intel Macs, can I use generic x86 asm?  Or is there a modified instruction set? Any information about post Intel.  Also: I know that on windows, asm can run in an emulated environment created by the OS to let the code think it's running on its own dedicated machine. Does OS X provide the same thing? I remember after Stargate: Universe was cancelled, that I read, somewhere on the web, either part of an interview or an article by one of the producers about what they were planning if there had been a third season.  (He said they weren't sure whether they'd set it soon after the ending of the second season, or later, or were going to do something else.)  He also wrote that, while he felt okay discussing that, he did not feel like he could reveal how the story about the superstructure the Destiny had found would turn out.  He said that was something the other two producers had worked out and he didn't want to reveal it and would leave it up to them to reveal it if they wanted to.  Was this ever revealed?  Did the other producers ever discuss or reveal anything about what was going to happen with that storyline?    Addition: I'm referring to the superstructure that is the message found in the background radiation throughout the universe, not anything from the planet builders or other easily seen physical structures. I see pictures online of everyone having all these Pokémon to catch being everywhere around them, but it seems like I can only ever see one or two. I live in a rural area, but even walking miles through the farmland, it's rare to find any Pokémon.  Why is this? How can I find more Pokémon? For some reason all of a sudden when I update cells in Excel, my equations are not being updated.  For example, I have a simple equation =SUM(C4:C16).  If I change any of the cells in C4-C16, the answer doesn't get updated...  I don't know what happened I've never seen this fail before.  Any ideas? How to sort a list of strings? What is the best way of creating an alphabetically sorted list in Python? Ways to prove Euler's formula for $\zeta(2n)$ When a PHP application makes a database connection it of course generally needs to pass a login and password. If I'm using a single, minimum-permission login for my application, then the PHP needs to know that login and password somewhere. What is the best way to secure that password? It seems like just writing it in the PHP code isn't a good idea. Did regular Americans speak the way actors in the 30s and 1940s did? I watch a lot of old movies, and I've noticed that American actors of the 1930s and 1940s often spoke in a quasi-generic-posh-British accent.  Katherine Hepburn's accent would be the perfect example. It seems exaggerated, and I imagine it was not common off the stage and screen. What was that? Was it just an accent or was it a dialect? Did real people actually speak that way?