I have a fixed-column long table, with much text inside, that spans about three pages. I set it using the supertabular package, and for the most part it is working  (I will still have to go back to manually tweak a few things once the document is complete). However, I sometimes wonder if longtable would have been a better choice.   Looking for troubleshooting tips for tables in this site, I noticed that there are a little over three times as many questions tagged for longtable than there are for supertabular. I could speculate that this is either because supertabular has fewer undesirable side-effects or because longtable is the preferred package, therefore more people will have problems with it. I have tried them both, and by putting enough time into them I have gotten the desired results; however, the question still nags me: which one is the right one (or the better one) for which type of long-table?
I have a pretty simple table that needs to span multiple pages. This seems like a job for either the / package or the  package.   The voting on the answers to this  suggest that longtable is the preferred package, yet xtab is much newer and has been revised since that question was asked.  What are the differences between xtab and longtable and when is one preferable to the other?
Identify $P(2014)$ if $P(i)=1/i$ for every positive integer $1\le i\le2013$ How can one motivate the relativistic momentum? Motivating the non-relativistic momentum $$\mathbf{p} = m\mathbf{v}$$ is quite easy: it is meant to represent the quantity of motion of the particle, and since the mass is one measure of quantity of matter it should be proportional to mass (how much thing is moving) and should be proportional to velocity (how fast and to where it is moving). Now, in Special Relativity the momentum changes. The new quantity of motion becomes $$\mathbf{p} = \dfrac{m\mathbf{v}}{\sqrt{1-\dfrac{v^2}{c^2}}}$$ Or, using $\gamma$ the Lorentz factor $$\mathbf{p} = \gamma(v) m\mathbf{v}$$ where I write $\gamma(v)$ to indicate that the velocity is that of the particle relative to the frame in which the movement is being observed. The need for this new momentum is because the old one fails to be conserved and because using the old one in Newton's second law leads to a law which is not invariant under Lorentz transformations. So the need for a new momentum is perfectly well motivated. What I would like to know is how can one motivate that the correct choice for $\mathbf{p}$ is the $\gamma(v)m\mathbf{v}$. There are some arguments using the mass: considering a colision, requiring momentum to be conserved, transform the velocity and then find how mass should transform. Although this work, it doesn't seem natural, and it is derived in one particular example. On my book there's even something that Einstein wote saying that he didn't think it was a good idea to try transforming the mass from $m$ to $M = \gamma(v)m$, that it was better to simply keep $\gamma$ on the new momentum without trying to combine it with the mass. So I would like to know: without resorting to arguments based on transformation of the mass, how can one motivate the new form of momentum that works for special relativity? App Store on Mojave: "We could not complete your purchase. cancelled" 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?! Earlier this year, I read a huge (1000+ pg) novel about a cloistered group of monks that sort of worshiped math. The story involved alternate dimensions or time travel or something. A big thing in the book was coordinates, containing data like for speed or something as an alternate axis. There were several rings of the monastery.   At some point the main character was called out of his monastery to never return. I'm hoping to figure out the name so I can discuss it with my book club. I want to block Facebook (the Facebook site) for concentrating purposes, but I don't want to break the share or like buttons on other pages (like a good article or a nice clip on YouTube I want to like or share). How can I do that? I use both Windows and Linux. How do I keep Python print from adding newlines or spaces? In python, if I say  print 'h'   I get the letter h and a newline.  If I say   print 'h',   I get the letter h and no newline.  If I say  print 'h', print 'm',   I get the letter h, a space, and the letter m.  How can I prevent Python from printing the space?  The print statements are different iterations of the same loop so I can't just use the + operator. I have updated my kubuntu 14.10 to kubuntu 15.04. And now after boot, when I enter my password on welcome screen, I will get black screen. It's looks like screen powered off. No cursor, no change brightness. Nothing. And when I try switch to text consoles (Ctrl+Alt+F1) nothing happening. If I doesn't login in welcome screen I can switch to text console. Compute the period of a decimal number a priori I noticed that , given an operation like $\frac{n}{m},\;n,m \in N$ that result in a periodic decimal number, computes really fast the length of the period.  E.g. $\frac{3923}{6173}$ has a period of 3086: .  I was wondering how this computation is done: is there some method to do this (except the trivial one of executing the division and looking for a sequence repetition) ? Use a shell variable in awk What does 'foo' really mean? I hope this qualifies as a programming question, as in any programming tutorial, you eventually come across 'foo' in the code examples. (yeah, right?)  what does 'foo' really mean?  If it is meant to mean nothing, when did it begin to be used so? I can't use the terminal while gedit command is running Convert 12-hour date/time to 24-hour date/time I have a tab delimited file where each record has a timestamp field in 12-hour format:     mm/dd/yyyy hh:mm:ss [AM|PM].   I need to quickly convert these fields to 24-hour time:     mm/dd/yyyy HH:mm:ss.   What would be the best way to do this? I'm running on a Windows platform, but I have access to sed, awk, perl, python, and tcl in addition to the usual Windows tools. Are battery packs allowed in hand luggage? The Pauli group for $n$-qubits is defined as $G_n=\{I,X,Y,Z \}^{\otimes n}$, that is as the group containing all the possible tensor products between $n$ Pauli matrices. It is clear that the Pauli matrices form a basis for the $2\times 2$ complex matrix vector spaces, that is $\mathbb{C}^{2\times 2}$. Apart from it, from the definition of the tensor product, it is known that the $n$-qubit Pauli group will form a basis for the tensor product space $(\mathbb{C}^{2\times 2})^{\otimes n}$.  I am wondering if the Pauli group in $n$-qubits forms a basis for the complex vector space where the elements of this tensor product space act, that is $\mathbb{C}^{2^n\times 2^n}$. Summarizing, the question would be, is $(\mathbb{C}^{2\times 2})^{\otimes n}=\mathbb{C}^{2^n\times 2^n}$ true?  I have been trying to prove it using arguments about the dimensions of both spaces, but I have not been able to get anything yet. Interpreting plot.lm() I had a question about interpreting the graphs generated by plot(lm) in R.  I was wondering if you guys could tell me how to interpret the scale-location and leverage-residual plots?  Any comments would be appreciated.  Assume basic knowledge of statistics, regression and econometrics. How can I lock a folder so that it CANNOT be erased? On my computer running Windows XP Pro SP3 I have a folder on my desktop that is very important. How can I lock it so that I can alter anything in it, but the folder itself cannot be removed without resetting a (lock/unlock?) switch? Abandoned colony of military engineer corps Can a plan "age" reach zero? Basic Web Development IDE/Editor like Dreamweaver? I've used Windows for many years, using Dreamweaver as my editor as it had a file tree which is based on a project (via Local, FTP or SFTP).  I need a web development IDE with the following functionality:   syntax highlighting for PHP, HTML, CSS, JavaScript  file tree - Local, FTP, SFTP, Project-Based (e.g. via the methods of Local/FTP/SFTP) in other words, like Dreamweaver can open multiple files (tabbed)   Additionally, I wouldn't mind features like debugging, class listings, etc, as long as I can hide them away. I am thinking of buying a camera to learn photography. Most of the time I'll be shooting portraits and landscapes. But I am not sure where I should start. Most of my friends tell me that I should get an entry level DSLR, but I am not sure if I have the persistence and enthusiasm to carry it all day in a backpack. But the camera on my cellphone doesn't seem to be enough to begin with.  So what I want is some expert advice (preferably with professional experience). Can most compact fixed-lens or mirrorless cameras fit the situations I mentioned? Or do I really need to go to a DSLR to get a tool to learn photography?