Cannot attach file and include a body while sending an email in Linux
How do I send a file as an email attachment using Linux command line?
Why does the following hold:  \begin{equation*} \displaystyle \sum\limits_{n=0}^{\infty} 0.7^n=\frac{1}{1-0.7} = 10/3\quad ? \end{equation*}  Can we generalize the above to      $\displaystyle \sum_{n=0}^{\infty} x^n = \frac{1}{1-x}$ ?   Are there some values of $x$ for which the above formula is invalid?  What about if we take only a finite number of terms? Is there a simpler formula?     $\displaystyle \sum_{n=0}^{N} x^n$   Is there a name for such a sequence?    This is being repurposed in an effort to cut down on duplicates, see here: Coping with  duplicate questions.  and here: . How to create a Windows 7 installation USB from OS X? I'm trying to create a Windows 7 installation USB (for use on a PC) from OS X.  I've tried following these instructions from a :   Insert the USB flash drive and run the command diskutil list to find out the disk name, we'll use /dev/disk1 as an example Now unmount the disk using diskutil unmountDisk /dev/disk1 dd if=/path/to/Win7.iso of=/dev/disk1 bs=8192   But the instructions don't work. When I insert the created USB drive into my PC and try to boot from it, I get this message:     Reboot and Select proper Boot device or Insert Boot Media in selected Boot device and press a key   What am I missing? New top bar quick reference guide / Where has the link to  gone? Since the new top bar has been rolled out - a number of different people, established and new users alike, have asked questions on where a specific link has disappeared to with the new top bar design. Where has the link to &lt;X&gt; gone? I noticed that $f(x) = x\phi(x)$ seems to be one-to-one, where $\phi(x)$ is Euler's Phi function.  In particular, I'm writing some numerical python code and the line I have looks something like  sorted([n*phi(n) for n in range(1,1000)])   and there are no duplicates in the list.  First, is it one-to-one?  Second, if it is, is there a simple proof sketch? I searched it a while and found some articles regarding Xperia Mini X10 also on XDA but I couldn't understand them easily. So I want help from you geeks who can give me the lighted way with simple steps to root my phone.    I want a step by step guide about to root this model. I'm a not much familiar with this technology so please guide me through some detailed answer. How to replace subscript symbols What differences exist between third-party and official lenses for Canon APS-C DSLRs? I am just another guy who just taken up photography as a social hobby who enjoys taking pics of everyday life, social events / parties &amp; some portraits. Need camera for short overseas trip (2-3 times a year), maybe some landscape pics.   I have done some research and have come up a list of main lenses that I am considering and hope you guys can offer some advice / comments to whether I should make those purchases.   Main reason why I chose "third party lenses" 'cos apparently they cost less, newer and are "award winning" - so I don't see the point of spending more for the original canon lens (which some maybe quite old - ie 3-5 yrs).   Sigma 17-70mm F2.8-4 DC MACRO OS HSM Lens (day to day lens) Sigma 85mm F1.4 EX DG HSM (for portrait &amp; bokeh effects) Wide angle lens (any suggestions)   Main questions / comments please...   Q1) What do you think of the lens choices that I have decided to build my kit?  Q2) Any wide angle lens that you will recommend? (third party or canon) or should I get wide angle zoom lens ? Q3) What are your thoughts that I chose all my lens from Third Party instead of Official Canon ones... is that a "smart move"? Suppose $X,Y$ and $Z$ are multivariate normal with means and full covariance matrix. The conditional expectation $E(X | Y)$ is well know. What is the conditional expectation of $E(X | Y,Z)$ if $Y$ and $Z$ (and $X$) are correlated? Standard textbooks only seem to cover the case when $Y$ and $Z$ are uncorrelated. Are humans the only animal that requires "clean water"? When I use the \tableofcontents macro in a document where the etoc package is loaded, latex pauses and reports an error. If I let the compilation continue a well formed pdf is generated.  Minimal example that can reproduce the error on my machine.  \listfiles \documentclass{article} \usepackage{etoc}  \begin{document} \tableofcontents‎‎ \end{document}   Output from pdflatex on the minimal example.  This is pdfTeX, Version 3.14159265-2.6-1.40.19 (TeX Live 2018) (preloaded format=pdflatex)  restricted \write18 enabled. entering extended mode (./mwe.tex LaTeX2e &lt;2018-04-01&gt; patch level 4 (/usr/local/texlive/2018/texmf-dist/tex/latex/base/article.cls Document Class: article 2014/09/29 v1.4h Standard LaTeX document class (/usr/local/texlive/2018/texmf-dist/tex/latex/base/size10.clo)) (/usr/local/texlive/2018/texmf-dist/tex/latex/etoc/etoc.sty (/usr/local/texlive/2018/texmf-dist/tex/latex/tools/multicol.sty)) (./mwe.aux)  ! Package inputenc Error: Unicode character ‎ (U+200E) (inputenc)                not set up for use with LaTeX.  See the inputenc package documentation for explanation. Type  H &lt;return&gt;  for immediate help.  ...                                                l.6 \tableofcontents‎                        ‎ ? R OK, entering \nonstopmode...  ! Package inputenc Error: Unicode character ‎ (U+200E) (inputenc)                not set up for use with LaTeX.  See the inputenc package documentation for explanation. Type  H &lt;return&gt;  for immediate help.  ...                                                l.6 \tableofcontents‎‎  [1{/usr/local/texlive/2018/texmf-var/fonts/map/pdftex/updmap/pdftex.map}] (./mwe.aux)   *File List*  article.cls    2014/09/29 v1.4h Standard LaTeX document class   size10.clo    2014/09/29 v1.4h Standard LaTeX file (size option)     etoc.sty    2018/02/23 v1.08n Completely customisable TOCs (JFB) multicol.sty    2018/04/20 v1.8s multicolumn formatting (FMi)  ***********   ) (see the transcript file for additional information)&lt;/usr/local/texlive/2018/te xmf-dist/fonts/type1/public/amsfonts/cm/cmbx12.pfb&gt;&lt;/usr/local/texlive/2018/tex mf-dist/fonts/type1/public/amsfonts/cm/cmr10.pfb&gt; Output written on mwe.pdf (1 page, 16281 bytes). SyncTeX written on mwe.synctex.gz. Transcript written on mwe.log. Why does "touch -a" also set the ctime? Is it touch(1) from coreutils-8.4-37.el6.x86_64 or my brain which is broken?  $ touch abc $ LANG=C stat abc   File: `abc'   Size: 0               Blocks: 0          IO Block: 4096   regular empty file Device: fd04h/64772d    Inode: 10485773    Links: 1 Access: (0664/-rw-rw-r--)  Uid: (3060399/ nodakai)   Gid: (  418/   quant) Access: 2016-10-14 18:42:06.189751847 +0800 Modify: 2016-10-14 18:42:06.189751847 +0800 Change: 2016-10-14 18:42:06.189751847 +0800 $ touch -a abc $ LANG=C stat abc   File: `abc'   Size: 0               Blocks: 0          IO Block: 4096   regular empty file Device: fd04h/64772d    Inode: 10485773    Links: 1 Access: (0664/-rw-rw-r--)  Uid: (3060399/ nodakai)   Gid: (  418/   quant) Access: 2016-10-14 18:42:17.374235446 +0800 Modify: 2016-10-14 18:42:06.189751847 +0800 Change: 2016-10-14 18:42:17.374235446 +0800 $ touch --help | grep 'access time'   -a                     change only the access time   As you see, it was not only atime but also ctime which was updated by touch -a !?!?  The filesystem is ext4 over LVM if that makes any differences. A curious integral The following integral has been on my mind for a while $$\int_0^\infty \frac{\sin(x)}{e^x-1}\,\mathrm d x \tag{$\dagger$}$$    Let us indicate the integrand as $f(x)=\frac{\sin(x)}{e^x-1}$. The following are a couple of observations.   The integrand can be extended by continuity in $0$ since $$\lim_{x\to 0}f(x)=\lim_{x\to 0}\frac{\frac{\sin(x)}{x}}{\frac{e^x-1}{x}}=1$$ This is the original reason I started playing around with this integral. Mathematica yields the result $$\int_0^\infty \frac{\sin(x)}{e^x-1}\,\mathrm d x=\frac{\pi}{2}\textrm{Coth}(\pi)-\frac 12 \approx 1.076674047$$ which, following numerical evidence, seems correct. Complex analysis may be useful here, since the integrand is a holomorphic function on $\mathbb C$. I tried writing $\sin(z)=\frac{e^{iz}-e^{-iz}}{2i}$, but I was not able to find an appropriate integration contour to solve the problem. The $-1$ in the denominator breaks the simmetry of the expression. This made most of my substitutions useless.   Can this integral be evaluated correctly, preferrably through complex analytic methods? Proving $\left(1+\dfrac{1}{1^3}\right)\left(1+\dfrac{1}{2^3}\right)\cdots\left(1+\dfrac{1}{n^3}\right)<3$ for all positive integers $n$ Prove that $\left(1+\dfrac{1}{1^3}\right)\left(1+\dfrac{1}{2^3}\right)\cdots\left(1+\dfrac{1}{n^3}\right)&lt;3$   for all positive integers $n$   This problem is copied from Math Olympiad Treasures by Titu Andreescu and Bogdan Enescu.They start by stating that induction wouldn't directly work here since the right hand side stays constant while the left increases.They get rid of this problem by strengthening the hypothesis.$$\left(1+\dfrac{1}{1^3}\right)\left(1+\dfrac{1}{2^3}\right)\cdots\left(1+\dfrac{1}{n^3}\right)\le3-\dfrac{1}{n}$$ and then proceed by induction.  The problem is that I can't find a motivation for the above change.I mean,we could have subtracted a lot of things from the RHS but what should nudge us to try $\dfrac{1}{n}$?The rest of the proof is quite standard,but I can't see how I am supposed to have thought of it.Is it just experience?Or is it a standard technique?A little guidance and motivation will be appreciated. Do we still need to avoid using frames and iframes for SEO? I thought frame and iframe were bad for SEO, but today I was doing a search for "numismatica" on Google.it.  The 3rd site is lemonete.com which is all made with frames. A competitor site (nummus.com) that has no frames ranks much lower when searching for the same word: "numismatica".  So can we use frames without taking an SEO hit now?  Any explanation (possibly simple) would be appreciated also about the fact the 2nd site ranks much lower. :) How can I see flags I cast from all sites? This morning I flagged something on one of the sites where I have fairly low rep. Now I can't remember which site it was. I've checked my flag history on about half of them, even editing the URL for the site where I have no helpful flags, and I can't find this flag. I've been to my network profile and looked at the Activity tab, but it only shows public things like asking, answering, commenting, editing, and reviewing.  Is there a way to see my flagging history across sites? Can we have such a feature, if it's not possible? "Think of" versus "think about" Could someone help me to understand when I should use think of and when think about in sentences?  What is the difference between using one or the other? Maximal Ideals in Ring of Continuous Functions Dummit and Foote, 7.4.33(a): Let $R$ be the ring of all continuous functions $[0,1] \to \mathbb{R}$ and let $M_c$ be the kernel of evaluation at $c \in [0,1]$, i.e. all $f$ such that $f(c) = 0$. Show that if $M$ is a maximal ideal in $R$ then $M = M_c$ for some $c$.    I am aware of proofs that use the compactness of $[0,1]$; however I have been told that a simpler proof exists using only the isomorphism theorems for rings along with basic facts about ideals. I have tried on my own to prove it this way but still have no success; is it possible?  (My attempts go something like: since $M$ is maximal, the quotient ring $R/M$ is a field. Then it would be nice to use the fact that $R/M$ has no zero divisors, but I can't quite make it work. Alternatively, consider $M \cap M_c$.) How do I set up file sharing between two Ubuntu laptops on my wireless network? I have two laptops running Ubuntu 12.04. Both connect to the same WIFI network to access internet.  How do I connect them to each other so that I can access files on one from another and vice versa?  Also, how do I manage the user permissions, etc. on them? Projectile Motion - Arrow In a 2D game, I simply want to draw the trajectory of an arrow in flight. With the code below, the trajectory (the parabola) looks right, but the angle (or rotation) or the arrow isn't.   float g = -9.8f; float x = (launchVelocity * time); float y = (launchVelocity * time) + (0.5f * g * (float)Math.Pow(time, 2)); float angle = (float)Math.Tanh(y / x);   What am I missing? Thanks. I've come across some strange interaction between overlay specification and \pause. Basically I have an itemize and after some text(or block). I want to step through the itemize and after that show the text/block.  I've tried to put a simple \pause between the itemize and the text, but in this way two slides are created, both with the full itemize and no text.  If I don't put the \pause the text is visible from the start(which I don't want).  I've already found a simple work-around: instead of using itemize[&lt;+-&gt;] I can specify the slides on the items(e.g item&lt;1-&gt;, ...item&lt;2-&gt;,... \pause), but I don't like this solution for some reasons:   I have to type more than before I have to hard-code the slide numbers This is solution is not robust. Modification on the item order, removal or addition of new items would break it. I think there has to be some better solution.   So, how should I do?  By the way, a minimal example:  \documentclass{beamer}  \usepackage[utf8]{inputenc} \usepackage{default}  \begin{document}  \begin{frame}     \begin{itemize}[&lt;+-&gt;]         \item A         \item B         \item C     \end{itemize}      \pause  % double pause here      Some text. \end{frame}  \end{document}