I'm trying to install VLC on Ubuntu by using the following commands:  sudo apt-get update &amp;&amp; sudo apt-get upgrade sudo apt-get install vlc   After trying to run the first command, an error is thrown:  E: Some index files failed to download. They have been ignored, or old ones used instead.   After running the second second command it gives another error:  E: Unable to correct problems, you have held broken packages.   What to do?
Possible Duplicate:             TL;DR: sudo apt-get install ... saying "Unable to correct problems, you have held broken packages."   The problem  I was trying to get the WebApps feature for PP and QQ following .  I ran the sudo add-apt-repository ppa:webapps/preview command to add the repository, but i got a connection error. Since I know my current ISP gives a shaky connection, I tried again and sure enough, it worked.  Then I ran sudo apt-get install unity-webapps-preview, but I realized we had to update apt-get first, so I hit Ctrl + C to stop it. Then I ran sudo apt-get update which worked w/o a fuss, but when I ran sudo apt-get install unity-webapps-preview again later, it showed an error message. Here's the dump:  Reading package lists... Done Building dependency tree        Reading state information... Done Some packages could not be installed. This may mean that you have requested an impossible situation or if you are using the unstable distribution that some required packages have not yet been created or been moved out of Incoming. The following information may help to resolve the situation:  The following packages have unmet dependencies:  unity-webapps-preview : Depends: xul-ext-unity but it is not going to be installed                          Depends: xul-ext-websites-integration but it is not going to be installed                          Depends: xul-ext-webaccounts but it is not going to be installed E: Unable to correct problems, you have held broken packages.   I think this might be because of me interrupting the earlier command. It hadn't got a chance to output anything, though — I stopped it pretty fast.  What I tried  Commands  I tried these:-   sudo apt-get install --fix-broken sudo apt-get autoclean sudo apt-get autoremove sudo apt-get -f install   But even after running sudo apt-get upgrade after every try, none of them worked.  Purging  I tried purging the repository, but that didn't work either. First, I got the package using sudoapt-get install ppa-purgeand then tried to purge the WebApps repo usingsudo ppa-purge ppa:webapps/preview`.  Manually installing dependencies  If you look at the error dump carefully, it says:     Depends: xul-ext-unity but it is not going to be installed   Depends: xul-ext-websites-integration but it is not going to be installed   Depends: xul-ext-webaccounts but it is not going to be installed   So I tried installing them manually. I ran sudo apt-get install xul-ext-unity, but got this:     Depends: xul-ext-websites-integration but it is not going to be installed   Breaks: firefox (>= 15.+) but 16.0~b6+build1-0ubuntu0.12.04.1~mfn4 is to be installed   I have no idea what the second part means, but I tried resolving the first. Running sudo apt-get install xul-ext-websites-integration gave:     xul-ext-websites-integration : Breaks: firefox (>= 15.+) but 16.0~b6+build1-0ubuntu0.12.04.1~mfn4 is to be installed   As a last resort, I tried sudo apt-get install xul-ext-webaccounts, but that gave the sane message too:     Breaks: firefox (>= 14.+) but 16.0~b6+build1-0ubuntu0.12.04.1~mfn4 is to be installed   What does Breaks: firefox (&gt;= 14.+) but 16.0~b6+build1-0ubuntu0.12.04.1~mfn4 is to be installed mean?  Research  I tried searching , looking at a couple of , looking at  and searching on AU, but to no avail. Help would be appreciated.
limit of integral $n\int_{0}^{1} x^n f(x) \text{d}x$ as $n\rightarrow \infty$ I am trying to solve the following problem at the level of a senior undergrad analysis level. So, the problem is as follows: We are given a function $f$ which is continuous on the interval $\left [ 0,1 \right ]$, and the question is to find the limit: $$\lim_{n\rightarrow \infty}\int_{0}^{1}x^{n}f(x)dx\;.$$ The second part of the problem is to deduce the following limit: $$\lim_{n\rightarrow \infty}n\int_{0}^{1}x^{n}f(x)dx\;.$$  For the first part: I just did the following: For every $0\leq x&lt; 1$: $x\leq M$, where $0&lt; M&lt; 1$. Then: $$\int_{0}^{1}x^{n}f(x)dx\leq M^{n}\int_{0}^{1}f(x)dx\;.$$ Then: $$\lim_{n\rightarrow \infty }\int_{0}^{1}x^{n}f(x)dx\leq \lim_{n\rightarrow \infty }M^{n}\int_{0}^{1}f(x)dx= 0.\int_{0}^{1}f(x)dx=0\;,$$ so $$\lim_{n\rightarrow \infty }\int_{0}^{1}x^{n}f(x)dx=\lim_{n\rightarrow \infty }f(1)\int_{0}^{1}1dx=f(1)\;.$$ Does that make sense? If not, please show me the correct one.  As for the second part, I have no idea what to do. Any help? How to input Traditional Chinese in pdfLaTeX I'm trying to write Chinese using pdfLaTeX. But currently I can only write Simplified Chinese Characters, If I try writing Traditional Chinese then the text wont show up.  This is what I have:  \documentclass{article} \usepackage{CJKutf8} \begin{document} \begin{CJK*}{UTF8}{gbsn} 文章内容。 \clearpage\end{CJK*} \end{document}   What would I need to do to get Traditional Chinese? Proving a direct product of groups is a group I use a brick and mortar bank for some of my savings. I’d love to get a CD interest rate closer to what Ally or other online banks offer.   Are brick and mortar banks will to negotiate with customers on interest rates? For instance, if I went into a branch and said I’m moving my money to Ally unless the bank matches Ally’s rates, do I have any chance of getting them to? Location of /etc/fstab in El Capitan I want to activate the . But I can't find the /etc/fstab on my mac. osx 10.11.5 El Capitan What CMYK values should I use for rich black, and how should I handle tints/shades? I'm working on a full color piece in Illustrator which has a few large black and grey areas.  I'd like the black to be a rich black. I was thinking c30 m30 y30 k100. What is the best ways to match my gray areas? Change bounding box of math glyphs in LuaTeX I'm trying to use the Garamond-Math font in LuaTeX (despite the documentation saying I should use it with XeTeX only :-). It's working more or less OK with LuaTeX, except for some unfortunate glyph combinations, mostly at the end of inline math, such as “where $T$ is the period”.  I used \fbox to draw the bounding box of the glyph and noticed that the bounding boxes are different in LuaTeX:        and in XeTeX:        In XeTeX the glyph fits almost entirely in the bounding box, but in LuaTeX it overshoots far too much.  I'm not a font guy, so I have no idea why this happens. I thought the bounding box was a property of the font, so in my imagination the result should be the same. Thus the first question is: what actually happens that the bounding boxes are different?  The second question, in the title, is: can I change the bounding box of specific glyphs (using LuaTeX) so that the output looks more like XeTeX's?  I tried manually adding some spacing after the glyphs, but this looks hideous and will go down the drain if I happen to change the font or engine, so I'd really like not to do that. I also tried using the italic correction \/ but it seems to have no effect in math.  Here's the code to produce the pictures above:  \documentclass{standalone} \usepackage{unicode-math} \setmathfont{Garamond-Math.otf} \begin{document} \fboxrule=1sp \fboxsep=0pt In Lua\TeX{} this \fbox{$T$} looks horrible, but the \fbox{$X$} looks OK. \Huge\fbox{$T$}\quad. \end{document}   I'm using TL 2018:  This is LuaTeX, Version 1.07.0 (TeX Live 2018)  (format=lualatex 2019.3.29)  13 APR 2019 12:43  restricted system commands enabled. **test.tex (./test.tex LaTeX2e &lt;2018-12-01&gt; Lua module: luaotfload-main 2019-02-14 2.96 luaotfload entry point I have two passports/nationalities. How do I use them when I travel? I am a citizen of two different countries, and have two passports.  How should I use my passports when traveling? "It looks straightforward, but actually it isn't" How can I show that "A center of a free group that is non-cyclic is trivial" ? When does the Death Saving Throw happen with respect to sources of automatic ongoing damage? If a character is knocked unconscious with 0HP with a source of automatically dealt damage, for example, into a fire, and takes damage from it each turn, does the automatic Death Saving Throw failure from taking damage at 0hp happen before or after the player's regular Death Saving Throw roll?  If the unconscious PC takes the auto-fail first then they effectively only get 1 Death Saving Throw to survive, because they'd autofail and roll a failure the first turn, then autofail again and die the next turn.   If they get to roll first, then they only effectively get two death saving throws before they die. Prevent specific sites from being overrepresented in the hot questions list Some sites appear far more often in the hot questions list than other sites. I don't have any hard data on that, as that kind of data is just not publicly available, but I'm pretty sure my subjective impression on that is reasonably accurate.  Those sites don't appear more often because they are inherently more interesting, but because they have certain voting and answering patterns that favor them in the hot questions algorithm. I would argue that the goal of the hot questions list is to present questions from a large variety of SE sites to the whole network, and to show possibly interesting questions to users that would not have found them otherwise.   To achieve this goal, the spots in the hot questions list should be distributed among all SE sites. The algorithm should try to get a good sampling of all sites, and it should try to normalize the results for varying voting behaviour. At the moment, sites that intrinsically get more votes and more answers per question seem favored in the algorithm.  So I think one part of the algorithm should try to identify questions that get an unusally high amount of votes and views for that site, and give the smaller sites a chance this way.  I'm not sure on how exactly this weighting should be done, as a complete normalization would likely not work across the huge difference in scale for all the SE sites.  As a specific example that the current algorithm is broken I'll present . I don't think any site should occupy a third of the whole list.   Here's another instance where one site is overrepresented at the top of the list: Prove that $x^2 + y^2 = z^4$ has infinitely many solutions with $(x,y,z)=1$.   Do I use the terms $x= r^2 - s^2$, $y = 2rs$, and $z = r^2 + s^2$ to prove this problem?  Thanks for any help. Why use sucrose rather than glucose in an injectable vaccine? How do I turn on workspaces? (Why do I only have one workspace?) Create Yosemite install disk on a Windows machine I have a 2009 Mac with a new blank SSD. I have a Snow Leopard install disk but it doesn't work (it was a replacement installer disk and has never worked), so I don't have a working OS X install.  I do have a Windows 7 machine.  How should I go about installing Yosemite? All instructions I can find require OS X at some point in the process. I can't even download it from the store unless I'm on a mac. Random operators Let $(\Omega, \mathcal F,P)$ be a probability spaces and $H$ be a Hilbert space. By a random operator $A$ from $H$ to $H$ we mean a linear continuous mapping from $H$ into the Frechet space $L_0^H (\Omega, \mathcal F,P)$ of all $H$-valued random variables. My question is: How Can we define $|A|$ and the adjoint $A^*$? My internet connection used to be a direct LAN connection to my provider. Back then, everything would load fine on both Windows and Ubuntu (dual boot). However, a while ago they started needing me to dial (PPPoE) using a username and password. Gateway, subnet mask, IP, DNS servers all stayed the same. But since then, I haven't been able to browse certain websites on Ubuntu, even though there have been no such issues on Windows. Some example websites are -  (although share.ovi.com loads fine, and nokia.com loads fine),  (works on Chrome(ium) and Opera but not on Firefox (both 3.6 and 4)) Mozilla  and other random websites.  Some of the websites that don't load show timeout messages and for some websites (like the moz addons one), the browser will keep trying to load without an end (I've left it like that even for hours but not noticed anything different happen).  I have tried changing the DNS servers to public ones. I have even tried booting from a Fedora LiveCD and then changing the DNS to those (and even to the ones of OpenDNS), but the exact same thing happens. What could be inherently wrong with some config within Linux itself that is causing this problem?  Does anyone know why this is happening and how it can be fixed?  Note: This question has been  on SU, but not gotten any responses.  Update: Just saw  that someone else was having similar problem and solved it by putting a NetworkManager.conf file in /etc/NetworkManager. What needs to be in that file? What is a comprehensive definition of Philosophy? Alternatively, is it impossible to define Philosophy? This is a pseudo- question, but it seems like it belongs here. I'm reading . Then I'm not able to figure out the difference between hard voting and soft voting in context to ensemble based methods.  I quote descriptions of them from the book. The first two images from the top are description for hard voting, and last one is for soft voting.        In my view hard voting is majority decision, but I don't understand soft voting and the reason why soft voting is better than hard voting. Would anyone teach me these?