I want to typeset the &lt; symbol in a string of text inside a math environment using the \text command from the amsmath package. However, for some reason it render something like  \text{&lt;-wrt}   to  ¡-wrt   Why does amsmath do that, and how can I stop it from 'interpreting' my text?
When typing &lt; or &gt; in LaTeX and compiling with pdflatex, the less than and greater than symbols appear at upside down exclamation points. I'm not in math mode.
What is a one-word synonym for "science lover"? I'm searching for a one-word synonym for "science lover". In my case, I love science and I self study it, but I never got a degree in Physics or Chemistry or any of these related subjects (except computer-science). But I enjoy experimenting stuff and see what's going on.  So, what would be a one-word good alternative for "science lover"?  The best one I found is learner, but that's more general I guess. Scientist is probably too much in my case. I saw sciencophile in another post, but I don't really like it–it sounds too complicated. Trace of a commutator is zero - but what about the commutator of $x$ and $p$? Operators can be cyclically interchanged inside a trace: $${\rm Tr} (AB)~=~{\rm Tr} (BA).$$ This means the trace of a commutator of any two operators is zero: $${\rm Tr} ([A,B])~=~0.$$ But what about the commutator of the position and momentum operators for a quantum particle? On the one hand: $${\rm Tr}([x,p])~=~0,$$ while on the other hand: $$[x,p]~=~i\hbar.$$ How does this work out? How is Gauss' Law (integral form) arrived at from Coulomb's Law, and how is the differential form arrived at from that? Unix epoch time to Java Date object I have a string containing the , and I need to convert it to a Java Date object.  String date = "1081157732"; DateFormat df = new SimpleDateFormat(""); // This line try {   Date expiry = df.parse(date);  } catch (ParseException ex) {   ex.getStackTrace(); }   The marked line is where I'm having trouble. I can't work out what the argument to SimpleDateFormat() should be, or even if I should be using SimpleDateFormat(). How do I wrap text in a pre tag? When a spaceship is experiencing a constant acceleration of $10m/s^2$, the astronauts will be moving at nearly the speed of light after about a year in the earth's reference frame. This means the spaceship's energy will start to diverge as a function of the speed $v$ so there will be a huge amount of energy necessary to increase the speed of the ship any further. This way, the speed of light can never be crossed.  All of this is clear to me, but all of this is also formulated in earth's reference frame. But from the astronaut's reference frame: the spaceship is simply accelerating at $10m/s^2$ and so the force on the spaceship is constant. Then why would we need huge amounts of energy to accelerate the spaceship?  For example, I read somewhere that the amount of energy that would be needed to accelerate a large spaceship to half the speed of light is more than 2000 times the current world annual energy consumption. How does this make sense in the astronaut's (non-inertial) frame? How do you use the Dungeon Defender's Portal Gun? The topic pretty much sums up my question. I have not yet figured out how the gun operates aside from the fact that it creates Portal portals. The weapon description indicates that it deals 250+ base damage, but how is that damage applied to the monsters? What is approximate error of Pythagorean Theorem vs. Haversine Formula in measuring distances on sphere at various scales? Many people when first trying to calculate distances between two longitude / latitude pairs  ask if Pythagorean theorem works as an appropriate distance function.  Most often people answer "no, the Pythagorean theorem only works on a 2D Euclidean plane." Rarely, however, do people mention the effect of scale and location on the sphere on how inaccurate the Pythagorean theorem is.  The basic idea being at very small scales, the surface of a sphere looks very much like a plane. At very large scales, it distances along the surface are more curved and therefore the difference between the incorrect Pythagorean Theorem and the correct Haversine Formula is greater.  Does anyone know a formula or rule of thumb that tells you the difference between the two distance measures based on the scale of the distance you are trying to measure?   I think having this explicitly would help in:   explaining why the Pythagorean Theorem isn't perfect; and in letting people who are looking for more "rough" distances know when Pythagoras actually will serve their purposes. This picture is a part of a table i am using, the terms subcases are vertically written but i cant center them vertically also in the next columns terms like A, B, etc are also not vertically centered. I made this table using tabulary package a. My code is  \begin{table}[H]  \centering  \caption{Saturation Table}  \label{tab:5}%  \begin{tabulary}{1\linewidth}{J J J J J J J J J J J J J}  \toprule  &amp; \textbf{Method} &amp; \multicolumn{1}{c}{\textbf{Parameters}} &amp; \textbf{Step 0} &amp; \textbf{Step 1} &amp; \textbf{Step 2} &amp; \textbf{Step 3} &amp; \textbf{Step 4} &amp; \textbf{Step 5} &amp; \textbf{Step 6} &amp; \textbf{Step 7} &amp; \textbf{Step 8} &amp; \textbf{Step 9} \\  \midrule  \multirow{4}[4]{*}{\begin{sideways}\textbf{Subcase A}\end{sideways}} &amp;  \multirow{2}[2]{*}{\textbf{A}} &amp; \textbf{No} &amp; 1 &amp; 2 &amp; 3 &amp; 4 &amp; 5 &amp; \textbf{6} &amp; &amp; &amp; &amp; \\[1mm]  &amp; &amp; \textbf{Maximum Saturation {(\%)}} &amp; 1 &amp; 2 &amp; 3 &amp; 4 &amp; 4 &amp; \textbf{5} &amp; &amp; &amp; &amp; \\  \cmidrule{2-13} &amp; \multirow{2}[2]{*}{\textbf{B}} &amp; \textbf{No} &amp; 1 &amp; 2 &amp; 3 &amp; 4 &amp; 5 &amp; 6 &amp; 7 &amp; \textbf{8} &amp; &amp; \\[1mm]  &amp; &amp; \textbf{Maximum Saturation {(\%)}} &amp; 6 &amp; 6 &amp; 7 &amp; 8 &amp; 9 &amp; 9 &amp; 19 &amp; \textbf{8} &amp; &amp; \\  \bottomrule  \end{tabulary}%  \end{table}% I want to compile my program with the latest version of gcc.  Ubuntu 14.04 comes with gcc 4.8.2, however there's 4.9.0 available, moreover, I see that it is available as a package: . I tried to install it  sudo apt-get install gcc-4.9   but it says  Reading package lists... Done Building dependency tree        Reading state information... Done Note, selecting 'gcc-4.9-base' for regex 'gcc-4.9' gcc-4.9-base is already the newest version. 0 upgraded, 0 newly installed, 0 to remove and 0 not upgraded.   Looks like it is already installed, just not as the default one? How do I utilize it to build my program? If Durmstrang and Beauxbatons were hidden from common knowledge, how did people from other schools go to them for the Triwizard tournament? So in GoF, they state that Beauxbatons and Durmstrang are hidden from view and don't have their locations public.     “Durmstrang’s another wizarding school?” said Harry      “Yes,” said Hermione sniffily, “and it’s got a horrible reputation.      According to An Appraisal of Magical Education in Europe, it puts a   lot of emphasis on the Dark Arts.”      “I think I’ve heard of it,” said Ron vaguely. “Where is it? What   country?”      “Well, nobody knows, do they?” said Hermione, raising her   eyebrows.      “Er — why not?” said Harry.      “There’s traditionally been a lot of rivalry between all the magic   schools. Durmstrang and Beauxbatons like to conceal their whereabouts   so nobody can steal their secrets,” said Hermione matter-offactly.   So how do students get to the other school for the Triwizard tournament? How to make a simple app from an applescript! I've got an applescript that I use to open files such as test.txt in vim, using the terminal.  I usually open a file by right-clicking it an selecting the service open in vim (this service is created by me and basically runs the applescript).  How do I build an actual program, that can be set in the "open with" option for a file?  This way, when I double click test.txt, the applescript gets run and the file gets opened in my vim in terminal.app.  I would also like to create custom icons that will be applied to all files I open using this app (using the "Change All..." button).  Where would I begin? Is this easy, because I'm just a novice -although I love programming and would spend much to to get to know all that is needed to do this.  the code is:  on open this_item      tell application "System Events"         if (count (processes whose name is "Terminal")) is 0 then             tell application "Terminal"                 activate                 do script with command "vim " &amp; (POSIX path of this_item) in front window             end tell         else             tell application "Terminal"                 activate                 tell application "System Events" to tell process "Terminal" to keystroke "t" using command down                 do script with command "vim " &amp; (POSIX path of this_item) in selected tab of the front window             end tell         end if     end tell  end open Reason for LCM of all numbers from 1 .. n equals roughly $e^n$ I computed the LCM for all natural numbers from 1 up to a limit $n$ and plotted the result over $n$.  Due to the fast-raising numbers, I plotted the logarithm of the result and was surprised to find a (more or less) identity curve ($x=y$).  In other words, $LCM(1, 2, 3, ..., n)$ appears to be roughly the value $e^n$.  Is a there a simple explanation on why this is so?  $LCM(a, b, c, …)$ shall be defined as the least common multiple of all arguments $a, b, c, …$ Height of Water 'Splashing' Suppose from a height $H$, I throw a ball of mass $M$ and radius $R$ with initial velocity $u$ into a pool of depth $x$ having a liquid with density $\rho$ and coefficient of viscosity $\eta$.  Upto what height will the Water Splash?   This may be a silly question! (Source : my brain) Assume every condition to be identical with no air resistance. Feel free to assume any other parameters if needed.  P.S. $\rightarrow$ I've see similar questions but some of them want an exact answer and some are not so direct while some are incomplete questions...  Small Note : We do not have to consider the highest 'single' drop... Just assuming almost every water droplet jumped upto a height $h$. Ideal conditions...  Feel free to assume the liquid as WATER if required! I installed Ubuntu 14.04.1 on one of my laptops and now I want distribute that exact installation to a few of my friends. I tried making an iso with Gparted on a live session but it makes a 500 GB file (I've only used around 8 GB) .   Thanks in Advance ! Where to find cross section data for $e^{-}$ + $p$ $\longrightarrow$ $p$ + $e^{-}$? Where to find cross section data for $e^{-}$ + $p$ $\longrightarrow$  $p$ + $e^{-}$ ?  does not include it. Constructing a continuous function whose graph seems 'special' I've been reading through Zorich's "Analysis I" book recently, and I came across this nice little exercise.  Let $f: [0,1]\to \mathbb R$ be a continuous function such that $f(0)=f(1)$. Show that    for any $n\in \mathbb N$ there exists a horizontal closed interval of length $\frac 1n$ with endpoints on the graph of this function; if the number $\ell$ is not of the form $\frac 1n$ there exists a function of this form on whose graph one cannot inscribe a horizontal chord of length $\ell$.   The first part can be proven like this: Consider $g: [0,(n-1)/n] \to \mathbb R$ given by $g(x) = f(x) - f(x+1/n)$. Then   $$\sum_{k=0}^{n-1} g(k/n) = 0$$  and therefore either all of these points are zero or there exists both a point where $g$ is positive and a point where $g$ is negative. By continuity, there must then also be a point where $g = 0$. So we are done.  Now, the second statement seemed rather counterintuitive, and I have given it some time now, but don't see a counterexample for $\ell &lt; 1/2$.  (For $\ell &gt; 1/2$ the function $f(x) = \sin(2\pi x)$ will do.)  Can anyone help me out?  Cheers, Is Ubuntu an open source software? Is Ubuntu an open source software (OSS)? View approximate number of users online Is there any way to view the number of users online at any given time (or even an approximation)?  This could be really useful to provide an indication of whether your question is likely to get answered any time soon.  It could also provide a bit of an indication for why your question is getting very low views - if there are only a few users online, then that could be the reason for little interest in a question, whereas if there are lots of users online and the question still doesn't garner many views, then maybe it needs to be rephrased or something.  I know that this can't be used definitively, but it could be used as a rough guide, and could also just be an item of interest.  Perhaps it could show the number of users that have been seen in the past 5 / 10 minutes? (Shouldn't be too hard, since each user page already shows the last time that they were seen). Spheres with csv file