When I am doing sudo apt-get update I got stuck at this :
apt-get stuck at 0 [Connecting to us.archive.ubuntu.com]
Why can't the end code of an environment contain an argument? Environments are allowed to have arguments, but reference to those arguments can only appear in the opening code of the environment, and not the closing code.  What is the reason for this, and are there preferred ways around it?  e.g.  \newenvironment{foo}[1]% {some code #1} % allowed {some code #1} % not allowed How should spare change be exchanged? So I have about $50 in pennies, dimes and nickels.  What would you do with it?  I'm asking because I don't think spending hours rolling up the change and taking it to the bank is the best/most creative thing.  More info:  I took the change to the bank (not rolled up).  The banker asked me if I knew the exact amount... when all I had was a huge bag of change weighing like 30-40 pounds :-p  I said I didn't know the exact amount.  So the banker put all the change into a different bag, gave me a little receipt and said look for a deposit to your account in about a week.  Next time I'll just find a coinstar machine. I don't like waiting a week to have my change counted.  Also I'm sure the banker could fish out the quarters and no one would be the wiser :-) What is Skynet's ultimate goal after defeating the resistance? Is it stated in any expanded universe what Skynet's plans were after wiping out the Human race (assuming that was its plan)?  Maybe space travel to colonise different planets or something else entirely? In US hotels, what happens if you skip checkout and just leave the hotel? Every time I check out of a hotel, they ask me if my stay went fine, let me review my incidental charges and ask if they should charge the credit card used to check in.   But what if I simply walk out of the hotel without formally "checking out"? They have my credit card on file and these days you don't even have to return your room key if you want to keep a souvenir. Would it be rude and create more work for hotel employees?  The question arose after spending 15 minutes in the check out queue at a major US hotel. Factorial of 0 - a convenience? Proof using Cauchy Integral Theorem $K \subset \mathbb{R}^n$ is compact iff it is closed and bounded I want to prove $\Leftarrow$.  I just need one more step, now. If I find a compact set that contains K, then it will finish the proof. Rudin take a k-cell to do that, but before it he proves that every k-cell is compact, and I think I can take a more simple compact to do this step. I has thinked in the closed ball, but don't know how to prove that it is compact. Can anyone help me to find this set, if it really exists? Thanks. When starring a message from the star board, it's not reflected in the main chat window If you click to star a post on the side (in the starred list), it changes color but not the star by the main chat area (it does add one to the number, but it doesn't change the color). Then when you click the star on the main chat area, it changes color to yellow but lowers the number by one  After clicking in sidebar:     After clicking in the main chat: What license to use while putting papers on the Arxiv? I am new to this and not sure what to make of all the options available. I am interested in putting a machine-learning-related preprint, which will potentially be submitted to places like NIPS/ICLR/ICML in the future.   arXiv.org perpetual, non-exclusive license to distribute this article (Minimal rights required by arXiv.org)  Creative Commons Attribution license (CC BY 4.0)  Creative Commons Attribution-ShareAlike license (CC BY-SA 4.0)  Creative Commons Attribution-Noncommercial-ShareAlike license (CC BY-NC-SA 4.0)  Creative Commons Public Domain Declaration (CC0 1.0) System.FinalException: Record is read-only: Trigger.updateCompetitors: line 24 Where does the phrase "on the lam" come from? According to the Online Etymological Dictionary, lam means:     "flight," as in on the lam, 1897, from a U.S. slang verb meaning "to run off" (1886), of uncertain origin, perhaps somehow from the first element of lambaste, which was used in British student slang for "beat" since 1590s.    Does anyone know of any other explanations? Prove that $\liminf x_n = -\limsup (-x_n)$ why normalize and the definition of directional derivative I'm not understanding how to solve this problem.  I think the problem lies in the fact that I don't understand why normalize and the definition of directional derivative... It's in Portuguese. The question would be: Determine the directional derivative of f in P in direction of vector u: How would you explain covariance to someone who understands only the mean? ...assuming that I'm able to augment their knowledge about variance in an intuitive fashion (  ) or by saying: It's the average distance of the data values from the 'mean' - and since variance is in square units, we take the square root to keep the units same and that is called standard deviation.  Let's assume this much is articulated and (hopefully) understood by the 'receiver'. Now what is covariance and how would one explain it in simple English without the use of any mathematical terms/formulae? (I.e., intuitive explanation. ;)  Please note: I do know the formulae and the math behind the concept. I want to be able to 'explain' the same in an easy to understand fashion, without including the math; i.e., what does 'covariance' even mean? "This is a favorite question" tooltip when not favorite I have a Microsoft XBOX 360 gamepad with the wireless adapter and I was wondering what I would have to install to use them with Ubuntu I do know that when using this on Windows I have to manually install the drivers for the wireless receiver (if that is relevant.) What's the batched Refactor Fields tool "field mapping" syntax in QGIS? In QGIS, there is this nice tool "Refactor Fields" in the Processing Toolbox :    Using it on a single layer is fairly straightforward.  However, when you plan on using it in a batch mode, one can see the "Fields mapping" textbox. I'm looking for an example of the syntax to be used there.  I haven't found any specific documentation yet. Can you help me resolve this paradox for a geodesic orbit? Does it maximize proper time to sit still rather than orbit for 1 year? Can sum of a rational number and its reciprocal be an integer? Can sum of a rational number and its reciprocal be an integer?   My brother asked me this question and I was unable to answer it.   The only trivial solutions which I could think of are $1$ and $-1$.  As to what I tried, I am afraid not much. I have never tried to solve such a question, and if someone could point me in the right direction, maybe I could complete it on my own.  Please don't misunderstand my question.   I am looking for a rational number $r$ where $r + \frac{1}{r}$ is an integer. Whenever adding a new wireless network, android seems to forget the network after disabling then re-enabling wifi. I am forced to manually connect to the network and enter the password each time. This also happens with open networks. The problem occurs on any wireless network, at home, work, public networks, etc.  Further inspection on the /data/misc/wifi/wpa_supplicant.conf file shows "disabled=1" added to the end of each network.    click image for larger version  This has been going on for weeks. Any help would be much appreciated.  Phone: Nexus 4 Version: 4.4.4