Using Courier font for mathematical equations (by ignoring math mode)
How to typeset the symbol “^” (caret/circumflex/hat)
Unable to lock the administration directory (/var/lib/dpkg/) is another process using it? Reading Chapter 2 of Koblitz's Introduction to Elliptic Curves and Modular Forms, I got stuck on the following question. I would like to proceed my reading, so I would appreciate any hint to this. I have no background in Algebraic Number Theory, but if someone explains in that language, I would like to see it and learn it as much as I can at this moment. References will also be appreciated!  Let $q$ be a power of prime $p$ such that $q \equiv 1 \mod 4$ and $p \nmid 2n$.  Question. Let $\chi_{4} : \mathbb{F}_{q}^{*} \rightarrow S^{1}$ be the character of order $4$, show that $\chi_{4}(-4) = 1$.  The hint in the book says we may show that $\chi_{4}(4) = \chi_{4}(-1) = 1$ for $q \equiv 1 \mod 8$ and $\chi_{4}(4) = \chi_{4}(-1) = -1$ for $q \equiv 5 \mod 8$.  If $q \equiv 1 \mod 8$, then $\chi_{4}(4) = \chi_{4}(2)^{2} = \chi_{2}(2) = \pm 1$, where $\chi_{j}$ denotes the character of order $j$. So I think $2$ must be quadratic residue in this case, but I cannot figure out why. I was thinking about writing a partial derivative macro that has a similar syntax to the . ()  The syntax could be like this:   \D{f}{x} expands to \frac{\partial f}{\partial x} \D{f}{x,y} expands to \frac{\partial^2 f}{\partial x\,\partial y} \D{f}{{x,2},y} expands to  \frac{\partial^3 f}{\partial x^2\,\partial y} et cetera for any number of derivatives.   Bonus points for an optional argument so that for instance   \D[subscript]{f}{{x,2},y} expands to f_{xxy}   I looked at the  package but the syntax is a little tedious.  For instance, to get \frac{\partial^3 f}{\partial x^2\,\partial y} with that package I would need to do \md{f}{3}{x}{2}{y}{}.  And it doesn't generalize to three variables.  Before I dive in I thought I'd ask the hive and see what's been done. I'm trying to find a simple way to create vertices where two objects intersect and delete the leftover internal planes + then join the meshes so that I have one hollow mesh to sculpt. The reason I need to know this is that on my first sculpt I just joined the meshes, but it didn't create vertices at the intersecting points so when I went to sculpt it just overlapped the meshes as you can see here in the neck.  Here is what I am working on now, it needs to be 1 hollow mesh Use a partitioned live usb I have a USB device and i'm trying to create it in a way that it has 2 partitions: one for a live linux disc and the other for document storage.  I created the partitions using gparted and and set a boot flag to the one I want to use as the live disc. Now, I have a usb like this:  Disk /dev/sdc: 14.6 GiB, 15623782400 bytes, 30515200 sectors Units: sectors of 1 * 512 = 512 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disklabel type: dos Disk identifier: 0xc3072e18  Device     Boot   Start      End  Sectors  Size Id Type /dev/sdc1       8439808 30515199 22075392 10.5G 83 Linux /dev/sdc2  *      51200  8439807  8388608    4G  b W95 FAT32   I then used dd to flash an Ubuntu iso to /dev/sdc2  sudo dd if=/dev/shm/ubuntu-17.04-desktop-amd64.iso of=/dev/sdc2 bs=4M   When the disc is flashed onto the usb drive, I try to boot from my laptop and it shows "Operating system not found". When i try to use qemu/kvm, it shows a kernel panic like this:    How would I be able to do this properly? Which is correct: "drive safe" or "drive safely"? According to , POST is used to create a resource:  The POST method is used to request that the origin server accept the entity enclosed in the request as a new subordinate of the resource identified by the Request-URI in the Request-Line.  According to , PUT is used to create or replace a resource:  The PUT method requests that the enclosed entity be stored under the supplied Request-URI. If the Request-URI refers to an already existing resource, the enclosed entity SHOULD be considered as a modified version of the one residing on the origin server. If the Request-URI does not point to an existing resource, and that URI is capable of being defined as a new resource by the requesting user agent, the origin server can create the resource with that URI.  So which HTTP method should be used to create a resource? Or should both be supported? What should I do if I want to be able to run a given program regardless of my current directory? Should I create a symbolic link to the program in the /bin folder? Can we have an option to disable notifications on community wiki posts? Pass in an array of Deferreds to $.when() Just doing this for revision, seems much harder than it should be, should I use $x=\tan u$ ? Any help appreciated. Statistical inference when the sample "is" the population Imagine you have to do reporting on the numbers of candidates who yearly take a given test. It seems rather difficult to infer the observed % of success, for instance, on a wider population due to the specifity of the target population. So you may consider that these data represent the whole population.   Are results of tests indicating that the proportions of males and females are different really correct? Does a test comparing observed and theoretical proportions appear to be a correct one, since you consider a whole population (and not a sample)? Basic Electronics Book Tikz: adjusting pin anchor I was looking for a possibility to adjust the anchor of the text of a pin. Tikz does not allow this out of the box.   This question was already asked on the mailing list , Sept. 2009 without any reply till today or feature addition to pgf/tikz:  \documentclass[tikz]{standalone}  \begin{document}      \begin{tikzpicture}[          every pin/.style={anchor=west},          every pin edge/.style={anchor=west}]          \node [pin=60:test] at (0,1) {};          \node [pin={[anchor=west]60:test}] at (0,0) {};      \end{tikzpicture}  \end{document}   There is also a question with a suggested workaround here on  by defining an aligned pin style consisting of another node positioned at the end of the pin using \tikzlastnode:  \tikzset{     aligned pin/.style args={[#1,#2]#3:#4}{         pin={[inner sep=0pt,%               pin distance=#2,% new option, default = 3ex               label={[append after command={%                     node[inner sep=0pt,%                         xshift=-0.1cm,% modified, default = 0                         at=(\tikzlastnode.#3),%                         anchor=#1,%                     ]{#4}%                 }%             ]center:{}}%         ]#3:{}}%     } }   In this code, I have added a second unnamed option for pin distance within the square brackets.  MWE using the workaround showing the desired result:  \documentclass[tikz]{standalone}  \tikzset{     aligned pin/.style args={[#1,#2]#3:#4}{         pin={[inner sep=0pt,%             pin distance=#2,% new option, default = 3ex             label={[append after command={%                     node[%                         inner sep=0pt,%                         xshift=-0.1cm,% modified, default = 0                         at=(\tikzlastnode.#3),%                         anchor=#1,%                     ]{#4}%                 }%             ]center:{}}%         ]#3:{}}%     } } \begin{document} \tikz[pin distance=15mm, every pin/.style={fill=blue,text=white}] \node [circle,draw,     aligned pin={[west,3ex]0:X-Value},%     aligned pin={[west,3ex]45:Y-Value},%     aligned pin={[west,3ex]90:Z-Value}] {my circle}; \end{document}     I would like to add further options such as pin edge to adjust the style of the edge. Another addition would be xshift to finetune the position of the text (and yshift).  Is it possible to change the workaround to allow named options with default values if not specified?  Usage could look like this (without using necessarily all options):  node[aligned pin={[pin anchor=west,pin distance=1cm,pin edge={thick}]90:{txt}}]{};   If someone is interested in the implementation of the pin feature in tikz see  and do a textsearch for pin.  Update after answer by Qrrbrbirlbel:  To achieve almost the same result as my MWE use following code  % use preamble from Qrrbrbirlbel answer \begin{document}  \begin{tikzpicture}[every pin/.append style=draw, every pin edge/.style={thick}] \node[c] [ pin={[pin anchor=south west,pin edge pin anchor=south west,pin distance=6ex]90:Z-Value}, pin={[pin anchor=west,pin edge pin anchor=west,pin distance=6ex]45:Y-Value}, pin={[pin anchor=west,pin edge pin anchor=west,pin distance=6ex]0:X-Value} ] at (0,0) {}; \end{tikzpicture}  \end{document}     However, I would like to finetune the text positioning using inner sep=0 and a slight shift:  \newlength{\xshiftlength} \setlength{\xshiftlength}{0.5\widthof{Z}}   Following works:  \tikzset{   pin inner xsep/.style={tikz@pin@post/.append style={inner xsep=#1}} }   Apparently xshift cannot be added in the same way. It shifts more than only the text. How could a pin text xshift be added? Installing .pkg with terminal ? Is it possible to install a .pkg using a terminal ? (I wanted to install an app through ssh). How to avoid "completely" dark shadow using directional light (as Sun) ? Look at my scene:     Sun is rising and as you can see the scene is realistic; I mean, that what is in shadow is almost completely dark. This is correct, but i would like something less "dark", like an HDR.  These are some parameters i'm using:     This is my unique Light in scene (Sun):     I'm using also a Post-Processing profile with "Eye Adaption" unflagged.  Can you suggest me what i've to change to make my object affected by shadow less.. dark ?   Thanks How to render lightning in Cycles How can you render a lightning bolt using Cycles? Which movie/TV show has an evil cyborg harvesting eyes from androids in a hidden town? I watched it maybe more than 8 to 12 years ago, but as far as I remember there was this place where androids (or maybe they were cyborgs) lived. (I think it was more like a hidden town). This guy finds them by accident (or at least I remember it that way) and tries to help them. I don't remember seeing any aliens or spaceships or anything like that. It was live-action, and I think US-based.  So, what I remember:   The bad guy is a human who has one red flashy robotic eye (not like terminators, it looks like a square eye patch above one of his eyes that functions like a second eye), he is collecting eyes from these androids/cyborgs. He also kills some of these androids/cyborgs but not all of them, some of them he just collects their eyes and doesn't kill (or get to kill). There was this woman who was a sexbot or something, she tried to give pleasure to the bad guy at some point, yet the bad guy added one of her eyes to his collection instead, but didn't/wasn't able to kill her. Towards the end she says something like "I used to give pleasure, now I only want to give pain" The human guy who found them tried to help them defend themselves from the bad guys, but they were in bad shape, many of them needed repair. To repair some of them, they needed spare parts they didn't seem to have, but one of the android/cyborg dudes said something like "we don't really bury our dead" and he brought a box of spare parts (or maybe android/cyborg body parts), they used these parts to repair some of the androids/cyborgs. There was this android/cyborg guy who was an assassin or something, but lost his fingers or hands, they couldn't find any hands compatible to his, but he said something like "I can still feel my trigger finger, just attach the weapons to my hands".   I remember it as a great movie/tv show, but I can't find anything about it. Can someone help me?  Please and thank you in advance... How do I clear Bash's cache of paths to executables? When I execute a program without specifying the full path to the executable, and Bash must search the directories in $PATH to find the binary, it seems that Bash remembers the path in some sort of cache. For example, I installed a build of Subversion from source to /usr/local, then typed svnsync help at the Bash prompt. Bash located the binary /usr/local/bin/svnsync for "svnsync" and executed it. Then when I deleted the installation of Subversion in /usr/local and re-ran svnsync help, Bash responds:  bash: /usr/local/bin/svnsync: No such file or directory   But, when I start a new instance of Bash, it finds and executes /usr/bin/svnsync.  How do I clear the cache of paths to executables? Let $p$ be a prime number and $G$ a non abelian group or order $p^3$. Prove that $Z(G) = [G,G]$.   I have already figured out that $|Z(G)| = p$, and that $G'=[G,G] \lhd G$.  Also, $|G'| = p$ or $p²$.  I suppose I'd have to prove that $G' \subset Z(G)$, but I've been trying and I have no idea how. Any hints? Thanks!