MathJax basic tutorial and quick reference

To see how any formula was written in any question or answer, including this one, right-click on the expression it and choose "Show Math As > TeX Commands". (When you do this, the '$' will not display. Make sure you add these. See the next point.) For inline formulas, enclose the formula in $...$. For displayed formulas, use $$...$$. These render differently. For example, type $\sum_{i=0}^n i^2 = \frac{(n^2+n)(2n+1)}{6}$ to show ∑ni=0i2=(n2+n)(2n+1)6 (which is inline mode) or type $$\sum_{i=0}^n i^2 = \frac{(n^2+n)(2n+1)}{6}$$ to shown∑i=0i2=(n2+n)(2n+1)6(which is display mode). For Greek letters, use \alpha, \beta, …, \omega: α,β,…ω. For uppercase, use \Gamma, \Delta, …, \Omega: Γ,Δ,…,Ω. For superscripts and subscripts, use ^ and _. For example, x_i^2: x2i. Groups. Superscripts, subscripts, and other operations apply only to the next “group”. A “group” is either a single symbol, or any formula surrounded by curly braces {…}. If you do 10^10, you will get a surprise: 1010. But 10^{10} gives what you probably wanted: 1010. Use curly braces to delimit a formula to which a superscript or subscript applies: x^5^6 is an error; {x^y}^z is xyz, and x^{y^z} is xyz. Observe the difference between x_i^2 x2i and x_{i^2} xi2. Parentheses Ordinary symbols ()[] make parentheses and brackets (2+3)[4+4]. Use \{ and \} for curly braces {}. These do not scale with the formula in between, so if you write (\frac{\sqrt x}{y^3}) the parentheses will be too small: (√xy3). Using \left(…\right) will make the sizes adjust automatically to the formula they enclose: \left(\frac{\sqrt x}{y^3}\right) is (√xy3). \left and\right apply to all the following sorts of parentheses: ( and ) (x), [ and ] [x], \{ and \} {x}, | |x|, \langle and \rangle ⟨x⟩, \lceil and \rceil ⌈x⌉, and \lfloor and \rfloor ⌊x⌋. There are also invisible parentheses, denoted by .: \left.\frac12\right\rbrace is 12}. Sums and integrals \sum and \int; the subscript is the lower limit and the superscript is the upper limit, so for example \sum_1^n ∑n1. Don't forget {…}if the limits are more than a single symbol. For example, \sum_{i=0}^\infty i^2 is ∑∞i=0i2. Similarly, \prod ∏, \int ∫, \bigcup ⋃, \bigcap ⋂, \iint ∬. Fractions There are two ways to make these. \frac ab applies to the next two groups, and produces ab; for more complicated numerators and denominators use {…}: \frac{a+1}{b+1} is a+1b+1. If the numerator and denominator are complicated, you may prefer \over, which splits up the group that it is in: {a+1\over b+1} is a+1b+1. Fonts Use \mathbb or \Bbb for "blackboard bold": CHNQRZ. Use \mathbf for boldface: ABCDEFGHIJKLMNOPQRSTUVWXYZ abcdefghijklmnopqrstuvwxyz. Use \mathtt for "typewriter" font: ABCDEFGHIJKLMNOPQRSTUVWXYZ abcdefghijklmnopqrstuvwxyz. Use \mathrm for roman font: ABCDEFGHIJKLMNOPQRSTUVWXYZ abcdefghijklmnopqrstuvwxyz. Use \mathsf for sans-serif font: ABCDEFGHIJKLMNOPQRSTUVWXYZ abcdefghijklmnopqrstuvwxyz. Use \mathcal for "calligraphic" letters: ABCDEFGHIJKLMNOPQRSTUVWXYZ Use \mathscr for script letters: ABCDEFGHIJKLMNOPQRSTUVWXYZ Use \mathfrak for "Fraktur" (old German style) letters: ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz. Radical signs Use sqrt, which adjusts to the size of its argument: \sqrt{x^3} √x3; \sqrt[3]{\frac xy} 3√xy. For complicated expressions, consider using{...}^{1/2} instead. Some special functions such as "lim", "sin", "max", "ln", and so on are normally set in roman font instead of italic font. Use \lim, \sin, etc. to make these: \sin x sinx, not sin x sinx. Use subscripts to attach a notation to \lim: \lim_{x\to 0}limx→0 There are a very large number of special symbols and notations, too many to list here; see this shorter listing, or this exhaustive listing. Some of the most common include: \lt \gt \le \ge \neq <>≤≥≠. You can use \not to put a slash through almost anything: \not\lt ≮ but it often looks bad. \times \div \pm \mp ×÷±∓. \cdot is a centered dot: x⋅y \cup \cap \setminus \subset \subseteq \subsetneq \supset \in \notin \emptyset \varnothing ∪∩∖⊂⊆⊊⊃∈∉∅∅ {n+1 \choose 2k} or \binom{n+1}{2k} (n+12k) \to \rightarrow \leftarrow \Rightarrow \Leftarrow \mapsto →→←⇒⇐↦ \land \lor \lnot \forall \exists \top \bot \vdash \vDash ∧∨¬∀∃⊤⊥⊢⊨ \star \ast \oplus \circ \bullet ⋆∗⊕∘∙ \approx \sim \simeq \cong \equiv \prec ≈∼≃≅≡≺. \infty \aleph_0 ∞ℵ0\nabla \partial ∇∂\Im \Re ℑℜ For modular equivalence, use \pmod like this: a\equiv b\pmod n a≡b(modn). \ldots is the dots in a1,a2,…,an\cdots is the dots in a1+a2+⋯+an Some Greek letters have variant forms: \epsilon \varepsilon ϵε, \phi \varphi ϕφ, and others. Script lowercase l is \ell ℓ. Detexify lets you draw a symbol on a web page and then lists the TEX symbols that seem to resemble it. These are not guaranteed to work in MathJax but are a good place to start. To check that a command is supported, note that MathJax.org maintains a list of currently supported LATEX commands, and one can also check Dr. Carol JVF Burns's page of TEX Commands Available in MathJax. Spaces MathJax usually decides for itself how to space formulas, using a complex set of rules. Putting extra literal spaces into formulas will not change the amount of space MathJax puts in: a␣b and a␣␣␣␣b are both ab. To add more space, use \, for a thin space ab; \; for a wider space ab. \quad and\qquad are large spaces: ab, ab. To set plain text, use \text{…}: {x∈s∣x is extra large}. You can nest $…$ inside of \text{…}. Accents and diacritical marks Use \hat for a single symbol ˆx, \widehat for a larger formula ^xy. If you make it too wide, it will look silly. Similarly, there are \bar ˉx and \overline ¯xyz, and \vec →x and \overrightarrow →xy and \overleftrightarrow ↔xy. For dots, as in ddxx˙x=˙x2+x¨x, use \dot and \ddot. Special characters used for MathJax interpreting can be escaped using the \ character: \$ $, \{ {, \_ _, etc. If you want \ itself, you should use\backslash ∖, because \\ is for a new line. (Tutorial ends here.) It is important that this note be reasonably short and not suffer from too much bloat. To include more topics, please create short addenda and post them as answers instead of inserting them into this post. discussion  faq  mathjax  reference share edited Feb 19 at 11:07 community wiki 55 revs, 18 users 52% MJD

12   Some capital Greek letters are the same as the Roman equivalents, so they are not separated in LATEX. For a capital beta, one must use something like \mathrm{B}: B –  robjohn♦  Aug 28 '12 at 2:06 36   for a beginner I find this site very helpful –  Monkey D. Luffy  Aug 28 '12 at 4:35 110   Thanks for putting this all together! –  J. M.  Aug 28 '12 at 11:03 3   Two related questions: How do I insert a table when asking a question? and How to show the integral symbol on this site? –  Martin Sleziak  Aug 28 '12 at 13:26 2   @Henning When I ranked features in my mind to decide whether to include them, \varphi and \varepsilon were very close to the threshhold for inclusion. Martin Sleziak has since added them, which I agree is a good idea. –  MJD  Aug 28 '12 at 16:33 11   A quick addition to point 11: If you want to use a sin-like symbol that is not already defined, the command is \operatorname: e.g., \operatorname{Spec} Agives SpecA. –  Charles Staats  Aug 28 '12 at 16:45 6   It might be useful to mention hanging subscripts for things like _5C_3 5C3. You could also mention \frac vs \dfrac. –  axblount  Aug 29 '12 at 18:09 3   My basic idea is that if a beginner can express a formula clearly, then someone else can come in and clean up the typesetting afterwards. I am considering getting rid of the section about \big, \left, and \right for this reason, and trimming the section on spacing. –  MJD  Aug 30 '12 at 2:06 5   Most of the references to TeX or LaTeX in this and the answers ought to be to MathJaX (the exception that I can see being the output of Detexify). I know this is a bit pedantic, but would it be alright to correct this? –  Loop Space  Sep 11 '12 at 14:13 2   @AndrewStacey Thanks for pointing this out. Let's by all means be as correct as possible, particularly when there's no extra cost. –  MJD  Sep 11 '12 at 14:15 4   @MJD Except that this is meant as a tutorial for those who aren't familiar with the distinction (and there really is a distinction: "slightly incompatible implementations" doesn't really fit the bill here). One thing tutorials often include is a "Where to find out more" section. This doesn't. Someone who doesn't know the distinction might be tempted to search for help on TeX or LaTeX instead and wonder why it doesn't work. –  Loop Space  Sep 11 '12 at 14:40 3   @axblount But that's precisely the wrong way around to think about it! The likelihood is that someone will look at this tutorial to figure out how to write something on the Maths-SX site: i.e., to use MathJaX. If they can't find help here, where do they go? If they have the idea that MathJaX is "just a javascript implementation of TeX" then they might think to look for help with TeX, but that is quite possibly not going to be helpful. –  Loop Space  Sep 11 '12 at 15:08 4   @axblount For a start, you've changed the goalposts: "LaTeX math expressions". LaTeX is so much more than just a way of typesetting maths! Second, I don't really know but it wouldn't take me long to cook one up. I don't use MathJaX so I haven't explored it. But I know, for example, that it can't handle catcode changes. Which means that I can't make ( and ) automatically resizeable. I can in LaTeX. –  Loop Space  Sep 11 '12 at 16:04 25   I wish I saw this post when I first joined. This post should be a main link on the home page. There should be a button under each box: NEW TO LATEX, CLICK HERE FOR EXAMPLES. This is extremely useful, concise. –  user1527227  May 31 '13 at 18:09 4   @MJD: I use \mathrm in many places; e.g. dx in integrals and derivatives and for operator names that don't need the full force of \operatorname. \mathrmwas intended for roman symbols in math mode; \text was intended for text because of the way it spaces things. See this TEX thread. Since I don't believe we can use preambles in MathJax, we can't use \DeclareMathOperator, though we can use \newcommand, but that is orthogonal to the use of \mathrm vs\text for math symbols. –  robjohn♦  Jun 10 '13 at 16:23  |   show 45 more comments

25 Answers

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Matrices Use $$\begin{matrix}…\end{matrix}$$ In between the \begin and \end, put the matrix elements. End each matrix row with \\, and separate matrix elements with&. For example, $$ \begin{matrix} 1 & x & x^2 \\ 1 & y & y^2 \\ 1 & z & z^2 \\ \end{matrix} $$ produces: 1xx21yy21zz2 MathJax will adjust the sizes of the rows and columns so that everything fits. To add brackets, either use \left…\right as in section 6 of the tutorial, or replace matrix with pmatrix (1234), bmatrix [1234], Bmatrix {1234},vmatrix |1234|, Vmatrix ∥1234∥. Use \cdots ⋯\ddots ⋱vdots ⋮ when you want to omit some of the entries: (1a1a21⋯an11a2a22⋯an2⋮⋮⋮⋱⋮1ama2m⋯anm) For "augmented" matrices, put parentheses or brackets around a suitably-formatted table; see arrays below for details. Here is an example: [123456] is produced by: $$ \left[ \begin{array}{cc|c} 1&2&3\\ 4&5&6 \end{array} \right] $$ The cc|c is the crucial part here; it says that there are three centered columns with a vertical bar between the second and third. For small inline matrices use \bigl(\begin{smallmatrix} ... \end{smallmatrix}\bigr), e.g. (abcd) is produced by: $\bigl( \begin{smallmatrix} a & b \\ c & d \end{smallmatrix} \bigr)$ share edited Jul 3 '15 at 18:06 Rory Daulton 24.4k 1 4 answered  Aug 28 '12 at 4:17 MJD 38.7k 6 27 53

8   This says "End each matrix row with \\". But there is no reason to end the LAST row of the matrix that way. The double backslash means: now go on to the next row. But there isn't any next row after the last one. –  Michael Hardy  Aug 28 '14 at 5:15 add a comment  |

up vote 133  down vote

Aligned equations Often people want a series of equations where the equals signs are aligned. To get this, use \begin{align}…\end{align}. Each line should end with \\, and should contain an ampersand at the point to align at, typically immediately before the equals sign. For example, √37=√732−1122=√732122⋅732−1732=√732122√732−1732=7312√1−1732≈7312(1−12⋅732) is produced by \begin{align} \sqrt{37} & = \sqrt{\frac{73^2-1}{12^2}} \\ & = \sqrt{\frac{73^2}{12^2}\cdot\frac{73^2-1}{73^2}} \\ & = \sqrt{\frac{73^2}{12^2}}\sqrt{\frac{73^2-1}{73^2}} \\ & = \frac{73}{12}\sqrt{1 - \frac{1}{73^2}} \\ & \approx \frac{73}{12}\left(1 - \frac{1}{2\cdot73^2}\right) \end{align} The usual $$ marks that delimit the display may be omitted here. share edited Apr 22 '15 at 7:36 answered  Aug 28 '12 at 4:28 MJD 38.7k 6 27 53

2   The AMS's Short Math Guide recommends the align environment over eqnarray in LaTeX. In MathJax the spacing seems to be the same , but align requires one less ampersand per line. –  Rahul  Aug 28 '12 at 4:41 2   Thanks. I was not sure whether to discuss that. A detailed argument against eqnarray is in this article. –  MJD  Aug 28 '12 at 4:51 Would you mind if I changed your example to use align then? –  Rahul  Aug 28 '12 at 5:34 @Rahul: Please go ahead and change anything that seems good to change. This is all CW. –  MJD  Aug 28 '12 at 5:44 Also, if you think you have a better example, please use it; I used the first one I found. –  MJD  Aug 28 '12 at 5:49 2   Correct me if I'm wrong, but I don't believe the $$ is necessary before and after the \begin{align}. I've certainly never used it. From experience, the \begin{align} puts you into math-display mode by itself. –  TravisJ  Apr 21 '15 at 12:24 Thanks, I did not know that. –  MJD  Apr 22 '15 at 7:37 I sometimes find that one line of this environment is too close to another, making them uncomfortable to read. The interline spacing can be adjusted by using input such as \\[1ex] instead of \\ . (And of course the 1 can be changed to another value such as 1.5 or .7 in order to get enough space but not too much.) –  David K  Jan 30 at 16:29 add a comment  |

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Definitions by cases (piecewise functions) Use \begin{cases}…\end{cases}. End each case with a \\, and use & before parts that should be aligned. For example, you get this: f(n)={n/2,if n is even3n+1,if n is odd by writing this: f(n) = \begin{cases} n/2, & \text{if $n$ is even} \\ 3n+1, & \text{if $n$ is odd} \end{cases} The brace can be moved to the right:if n is even:n/2if n is odd:3n+1}=f(n) by writing this: \left. \begin{array}{l} \text{if $n$ is even:}&n/2\\ \text{if $n$ is odd:}&3n+1 \end{array} \right\} =f(n) To get a larger vertical space between cases we can use \\[2ex] instead of \\. For example, you get this: f(n)={n2,if n is even3n+1,if n is odd by writing this: f(n) = \begin{cases} \frac{n}{2}, & \text{if $n$ is even} \\[2ex] 3n+1, & \text{if $n$ is odd} \end{cases} (An ‘ex’ is a length equal to the height of the letter x; 2ex here means the space should be two exes high.) share edited Jan 25 at 22:09 MichaelChirico 2,237 1 4 answered  Aug 28 '12 at 4:34 MJD 38.7k 6 27 53

@MJD Do we have to use the additional instruction \displaystyle when the formulas displayed are more complex ? –  jibe  Jul 1 '14 at 14:43 @jibs \displaystyle is enabled automatically in displays, for example between $$…$$. You should not ever have to use it. –  MJD  Jul 1 '14 at 14:50 @jibe In general, the separate cases in this notation should be in text style unless they are very very complex (and then, the { notation is just wrong anyways). –  yo'  Aug 25 '14 at 9:53 add a comment  |

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Symbols In general, you have to search in long tables about a specific symbol you're looking for, things like Ψ, δ, ζ, ≥, ⊆ ... And it turns out that this operation can be frustrating and time consuming, which can cause the buddy to abandon writing the complete LATEX sentence in his answer, or in some cases, the complete answer itself. That's why the tool that I will present you in this post was conceived. Basically, it is a LATEX handwritten symbol recognition. Example in image: Here is the website: Detexify² No more frustration. share answered  Oct 14 '13 at 20:15 community wiki user93957

7   Amazing site!!! –  Silent  Oct 16 '13 at 3:30 2   Wow. Thanks! This really helped –  Siyanda  May 5 '14 at 20:59 add a comment  |

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Arrays It is often easier to read tables formatted in MathJax rather than plain text or a fixed width font. Arrays and tables are created with the array environment. Just after \begin{array} the format of each column should be listed, use c for a center aligned column, r for right aligned, l for left aligned and a | for a vertical line. Just as with matrices, cells are separated with & and rows are broken using \\. A horizontal line spanning the array can be placed before the current line with \hline. For example,nLeftCenterRight10.2411252−1189−83−2020001+10i $$ \begin{array}{c|lcr} n & \text{Left} & \text{Center} & \text{Right} \\ \hline 1 & 0.24 & 1 & 125 \\ 2 & -1 & 189 & -8 \\ 3 & -20 & 2000 & 1+10i \end{array} $$ Arrays can be nested to make an array of tables. For example,min012300000101112012230123max012300123111232222333333Δ012300123110122210133210 As the source for the preceding array is long, please right-click on one of the tables and choose Show Math As ▸ TeX Commands. share edited Aug 28 '14 at 5:17 community wiki 8 revs, 6 users 47% robjohn

3   You'll have to wrap the contents of each cell in \text if you don't want allitalics,weird−lookingspacing,an′oddapostrophes. –  Rahul  Aug 29 '12 at 21:30 @RahulNarain: True. I used words just for illustration, but I guess the example was slightly misleading. If you'd like to modify it please go ahead.–  axblount  Aug 29 '12 at 22:00 1   Thanks! I like your numeric example better, since the widths of the entries are different enough that the alignment differences are visually clear. –  MJD  Aug 30 '12 at 1:37 @robjohn how do you use | while typing , i don't find it in my keyboard...... –  ABC  Mar 28 '13 at 12:05 @exploringnet: on my keyboard, it is the shifted backslash. It may be in different places (or absent) depending on your keyboard. On my mobile device (iPhone), it is in the shifted numerics, to the right of the backslash. In mathmode, \vert gives | and \mid gives ∣, but neither works in the column spec for an array. If you cannot type it on your keyboard, you can alwaays copy and paste it from another document. –  robjohn♦  Mar 28 '13 at 17:39 It should perhaps be mentioned, that in nested arrays there seems to be no option to synchronize column-widths and/or row-heights over the top-level. I didn't find a solution such that if two arrays are stacked vertically one could make their column-widths matching/fit. –  Gottfried Helms  Aug 26 '13 at 9:16 1   This could also be convenient for some people, althought it destroys the joy of writing tables in LATEX by hand! –  nullgeppetto  Jun 3 '14 at 14:18 @Rahul: why did regulars not press developers to enhance HTML formatting instead of doing inconvenient and resource-devouring detours through MathJax? When a table contains (mostly) formulæ, the use of a formula-formatting engine looks determined. But when one wants just a table, why should it run software with completely different purpose? I once tried to speak about it at meta.SE, but was gagged. –  Incnis Mrsi  Dec 3 '14 at 12:11 @IncnisMrsi What kind of pressure could we apply: bribery, threats, kidnapping? A feature request was made, supported by SE communities, and declined by SE (on technical grounds, as they say). At least we have the MathJax workaround, with all of its flaws: SO and others have nothing. –  404  Dec 3 '14 at 15:55 add a comment  |

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Fussy spacing issues These are issues that won't affect the correctness of formulas, but might make them look significantly better or worse. Beginners should feel free to ignore this advice; someone else will correct it for them, or more likely nobody will care. Don't use \frac in exponents or limits of integrals; it looks bad and can be confusing, which is why it is rarely done in professional mathematical typesetting. Write the fraction horizontally, with a slash: BadBettereiπ2eiπ2eiπ/2∫π2−π2sinxdx∫π/2−π/2sinxdx The | symbol has the wrong spacing when it is used as a divider, for example in set comprehensions. Use \mid instead: BadBetter{x|x2∈Z}{x∣x2∈Z} For double and triple integrals, don't use \int\int or \int\int\int. Instead use the special forms \iint and \iiint:BadBetter∫∫Sf(x)dydx∬Sf(x)dydx∫∫∫Vf(x)dzdydx∭Vf(x)dzdydx Use \, to insert a thin space before differentials; without this TEX will mash them together: BadBetter∭Vf(x)dzdydx∭Vf(x)dzdydx share edited Jun 4 '13 at 15:47 community wiki 7 revs MJD

2   I think the first adjusted fraction looks better than the original, but I don't like the second. In any case, this minor spacing imbalance is too peripheral to belong in a basic MathJax tutorial IMO. Too likely to scare people away rather than make them feel helped. –  Henning Makholm  Aug 31 '12 at 21:05 1   @Henning Do you mean that the fraction example is too unimportant even to appear in an addendum on fussy spacing, or that the fussy spacing article is too unimportant to appear as an addendum to the tutorial? –  MJD  Aug 31 '12 at 23:57 1   I was talking specifically about the fraction example. Mostly I'm concerned that somebody will come away thinking, Eeek! Do I have to worry about THAT to use the site? But it's also arguable that the disclaimer at the top of the answer ought to take care of that. –  Henning Makholm  Sep 1 '12 at 21:13 1   @MJD I like the less space, but what if we want to list the bounds for multiple integrals? Like if we have say 3 integrals and we have 3 separate bounds for each how would we list each one? Or do we have to do \int_bound1^bound2\int_bound3^bound4\int_bound5^bound6?? –  TheHopefulActuary  Nov 19 '12 at 19:45 @Kyle I think that's exactly what you do in that case. –  MJD  Nov 19 '12 at 20:09 16   Worth nothing you can use \middle with | to get it to work with \left and \right, like \left\{x\middle | \frac{x^2}{2} \in \mathbb{z}\right\}: {x|x22∈z} –  asmeurer  Jun 9 '13 at 22:49 Thanks very much! I wanted to do that, but didn't know how. –  MJD  Jun 10 '13 at 15:47 add a comment  |

up vote  52 down vote

Colors Named colors are browser-dependent; if a browser doesn't know a particular color name, it may render the text as black. The following colors are standard in HTML4 and CSS2 and should be interpreted the same by most browsers:\color{black}{text}text\color{gray}{text}text\color{silver}{text}text\color{white}{text}text\color{maroon}{text}text\color{red}{text}text\color{yellow}{text}text\color{lime}{text}text\color{olive}{text}text\color{green}{text}text\color{teal}{text}text\color{aqua}{text}text\color{blue}{text}text\color{navy}{text}text\color{purple}{text}text\color{fuchsia}{text}text HTML5 and CSS 3 define an additional 124 color names that will be supported on many browsers. Math Stack Exchange's default style uses a light-colored page background, so avoid using light colors for text. Stick to darker colors like maroon, green, blue, and purple, and remember also that 7–10% of men are color-blind and have difficulty distinguishing red and green. The color may also have the form #rgb where r,g,b are in the range or 0–9, a–f and represent the intensity of red, green, and blue on a scale of 0–15, with a=10, b=11, … f=15. For example: #000text#00Ftext#0F0text#0FFtext#F00text#F0Ftext#FF0text#FFFtext #000text#005text#00Atext#00Ftext#500text#505text#50Atext#50Ftext#A00text#A05text#A0Atext#A0Ftext#F00text#F05text#F0Atext#F0Ftext#080text#085text#08Atext#08Ftext#580text#585text#58Atext#58Ftext#A80text#A85text#A8Atext#A8Ftext#F80text#F85text#F8Atext#F8Ftext#0F0text#0F5text#0FAtext#0FFtext#5F0text#5F5text#5FAtext#5FFtext#AF0text#AF5text#AFAtext#AFFtext#FF0text#FF5text#FFAtext#FFFtext You can have a look here for quick reference on colors in HTML. share edited Aug 11 '14 at 18:54 community wiki 6 revs, 3 users 70% MJD

2   We should add that colors can be used on items other than text, such as variables and operators. The '\color' command applies to the next item: surround anything longer with braces. –  Rory Daulton  Feb 21 '15 at 20:30 add a comment  |

up vote  52 down vote

System of equations Use \begin{array}…\end{array} and \left\{…\right.. For example, you get this: {a1x+b1y+c1z=d1a2x+b2y+c2z=d2a3x+b3y+c3z=d3 by writing this: $$ \left\{ \begin{array}{c} a_1x+b_1y+c_1z=d_1 \\ a_2x+b_2y+c_2z=d_2 \\ a_3x+b_3y+c_3z=d_3 \end{array} \right. $$ Alternatively we can use \begin{cases}…\end{cases}. The same system {a1x+b1y+c1z=d1a2x+b2y+c2z=d2a3x+b3y+c3z=d3 is produced by the following code $$\begin{cases} a_1x+b_1y+c_1z=d_1 \\ a_2x+b_2y+c_2z=d_2 \\ a_3x+b_3y+c_3z=d_3 \end{cases} $$ To align the = signs use \begin{aligned}...\end{aligned} and \left\{…\right. (see asmeurer's comment){a1x+b1y+c1z=d1+e1a2x+b2y=d2a3x+b3y+c3z=d3 whose code is $$ \left\{ \begin{aligned} a_1x+b_1y+c_1z &=d_1+e_1 \\ a_2x+b_2y&=d_2 \\ a_3x+b_3y+c_3z &=d_3 \end{aligned} \right. $$ To align the = signs and the terms as in{a1x+b1y+c1z=d1+e1a2x+b2y=d2a3x+b3y+c3z=d3 use array with l (for "align left"; there are also c and r) parameters $$ \left\{ \begin{array}{ll} a_1x+b_1y+c_1z &=d_1+e_1 \\ a_2x+b_2y &=d_2 \\ a_3x+b_3y+c_3z &=d_3 \end{array} \right. $$ Vertical space between equations. As explained in Definition by cases to get a larger vertical space between equations we can use \\[2ex] instead of\\. The system {a1x+b1y+c1z=p1q1a2x+b2y+c2z=p2q2a3x+b3y+c3z=p3q3 is generated by the following code $$\begin{cases} a_1x+b_1y+c_1z=d_1 \\[2ex] a_2x+b_2y+c_2z=d_2 \\[2ex] a_3x+b_3y+c_3z=d_3 \end{cases} $$ in comparison with {a1x+b1y+c1z=p1q1a2x+b2y+c2z=p2q2a3x+b3y+c3z=p3q3 whose code is $$\begin{cases} a_1x+b_1y+c_1z=\frac{p_1}{q_1} \\ a_2x+b_2y+c_2z=\frac{p_2}{q_2} \\ a_3x+b_3y+c_3z=\frac{p_3}{q_3} \end{cases} $$ In response to elect's comment. The following code $$ \left\{ \begin{array}{l} 0 = c_x-a_{x0}-d_{x0}\dfrac{(c_x-a_{x0})\cdot d_{x0}}{\|d_{x0}\|^2} + c_x-a_{x1}-d_{x1}\dfrac{(c_x-a_{x1})\cdot d_{x1}}{\|d_{x1}\|^2} \\[2ex] 0 = c_y-a_{y0}-d_{y0}\dfrac{(c_y-a_{y0})\cdot d_{y0}}{\|d_{y0}\|^2} + c_y-a_{y1}-d_{y1}\dfrac{(c_y-a_{y1})\cdot d_{y1}}{\|d_{y1}\|^2} \end{array} \right. $$ produces {0=cx−ax0−dx0(cx−ax0)⋅dx0∥dx0∥2+cx−ax1−dx1(cx−ax1)⋅dx1∥dx1∥20=cy−ay0−dy0(cy−ay0)⋅dy0∥dy0∥2+cy−ay1−dy1(cy−ay1)⋅dy1∥dy1∥2 share edited Jun 29 '15 at 11:10 community wiki 7 revs, 2 users 94% Américo Tavares

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up vote 51  down vote

Continued fractions To make a continued fraction, use \cfrac, which works just like \frac but typesets the results differently: x=a0+12a1+22a2+32a3+44a4+⋯ Don't use regular \frac or \over, or it will look awful: x=a0+12a1+22a2+32a3+44a4+⋯ You can of course use \frac for the compact notation: x=a0+12a1+22a2+32a3+44a4+⋯ Continued fractions are too big to put inline. Display them with $$…$$ or use a notation like [a0;a1,a2,a3,…]. share answered  Aug 31 '12 at 19:46 community wiki MJD

The RHS of the following continued fractiona1b1+a2b2+a3b3+⋱=a1b1+a2b2+a3b3+… can be typeset with the \genfrac command '{\genfrac{}{}{}{}{a_1}{b_1}} {\genfrac{}{}{0pt}{}{}{+}} {\genfrac{}{}{}{}{a_2}{b_2}} {\genfrac{}{}{0pt}{}{}{+}} {\genfrac{}{}{}{}{a_3}{b_3}} {\genfrac{}{}{0pt}{}{}{+\dots}}' –  Américo Tavares  Sep 17 '12 at 20:39 I wonder if something like 12+34 would be good enough? It is much simpler. (\frac12{\vphantom{1}\atop+}\frac34) –  MJD  Sep 17 '12 at 22:30 Yes, it is. I didn't mention it because in User’s Guide for the amsmath Package it is written the following: "Note. For technical reasons, using the primitive fraction commands \over, \atop, \above in a LATEX document is not recommended (see, e.g., amsmath.faq)." –  Américo Tavares  Sep 17 '12 at 22:44 1   Happily, we are not writing LATEX documents here. –  MJD  Sep 17 '12 at 22:44 4   Or write \underset{j=1}{\overset{\infty}{\LARGE\mathrm K}}\frac{a_j}{b_j}=\cfrac{a_1}{b_1+\cfrac{a_2}{b_2+\cfrac{a_3}{b_3+\ddots}}} to get∞Kj=1ajbj=a1b1+a2b2+a3b3+⋱. –  Américo Tavares  Jan 24 '13 at 9:15 1   @AméricoTavares Or use \mathop instead of \overset and \underset: \mathop{\LARGE\mathrm K}_{i=1}^\infty \frac{a_i}{b_i}∞Ki=1aibi –  AlexR  Feb 21 '15 at 20:48 @AlexR It's easier, thanks! –  Américo Tavares  May 17 '15 at 13:24 @AméricoTavares, Why don't you edit the answer and put this extremely helpful command into there, I think that would be more helpful. –  Subhadeep Dey  Jan 24 at 15:44 add a comment  |

up vote  49  down vote

Crossing things out Use \require{cancel} in the first formula in your post that requires cancelling; you need it only once per page. Then use: y+\cancel{x}y+x\cancel{y+x}y+xy+\bcancel{x}y+xy+\xcancel{x}y+xy+\cancelto{0}{x}y+x0\frac{1\cancel9}{\cancel95} = \frac151995=15 Use \require{enclose} for the following: \enclose{horizontalstrike}{x+y}x+y\enclose{verticalstrike}{\frac xy}xy\enclose{updiagonalstrike}{x+y}x+y\enclose{downdiagonalstrike}{x+y}x+y\enclose{horizontalstrike,updiagonalstrike}{x+y}x+y \enclose can also produce enclosing boxes, circles, and other notations; see MathML menclose documentation for a complete list. share edited Aug 4 '14 at 15:20 community wiki 4 revs MJD

2   Can I use \enclose{counterstrike}? :P –  Akiva Weinberger  Jul 27 '15 at 19:19 1   That sneaky 19/95=1/5. Nice one! –  Darth Geek  Dec 8 '15 at 23:57 add a comment  |

up vote  38  down vote

Additional decorations \overline: ¯A ¯AA ¯AAA \underline: B_ BB_ BBB_ \widetilde: ˜C ~CC ~CCC \widehat: ˆD ^DD ^DDD \fbox: E EE EEE \underleftarrow: F← FF← FFF← \underrightarrow: G→ GG→ GGG→ \underleftrightarrow: H↔ HH↔ HHH↔ \overbrace: ⏞(n−2)+⏞(n−1)+n+(n+1)+(n+2) \underbrace: (n−2)+(n−1)+n+(n+⏟1)+(n+⏟2) \overbrace and \underbrace accept a superscript or a subscript, respectively, to annotate the brace. For example, \underbrace{a\cdot a\cdots a}_{b\text{ times}} isa⋅a⋯a⏟b times Additional accents \check: ˇI \acute: ˊJ \grave: ˊK share edited Jun 9 '14 at 5:10 community wiki 6 revs, 4 users 71% Américo Tavares

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up vote  38 down vote

\implies (⟹) is a marginally preferable alternative to \Rightarrow (⇒) for implication. There's also \iff ⟺ and \impliedby ⟸. \to (→) is preferable to \rightarrow or \longrightarrow for things like f:A→B. The reverse is \gets (←). share edited Feb 15 at 19:29 community wiki 3 revs, 3 users 75% leonbloy

1   Why is it preferable? –  MJD  Jul 9 '13 at 20:00 9   implies looks nicer as the arrow is longer and \to is quicker to right (and it's also what you say in your head while typing it). at least that's what I think. –  John Salvatierrez  Jul 29 '13 at 13:21 1   Remember the difference between \to and \mapsto as in T:R→R,x↦x+1 produced by T:\mathbb R\to \mathbb R,\; x\mapsto x+1 –  yo'  Aug 25 '14 at 9:57 2   I prefer using \to when it appears as part of a larger propositional formula, rather than at the top level, i.e. p∧((q∨r)→s), because the spacing is similar to that of other binary operators. \implies is better for sentence- or clause-level implications, or in displays, i.e.x+2=4−x⟹x=1. –  Mario Carneiro  Feb 2 '15 at 14:22 add a comment  |

up vote 37  down vote

Tags & References For longer calculations (or referring to other post's results) it is convenient to use the tagging/labelling/referencing system. To tag an equation use\tag{yourtag}, and if you want to refer to that tag later on, add \label{somelabel} right after the \tag. It is not necessary that yourtag and somelabel are the same, but it usually is more convenient to do so: $$ a := x^2-y^3 \tag{*}\label{*} $$ a:=x2−y3 In order to refer to an equation, just use \eqref{somelabel} $$ a+y^3 \stackrel{\eqref{*}}= x^2 $$ a+y3(*)=x2 or \ref{somelabel} Equations are usually referred to as $\eqref{*}$, but you can also use $\ref{*}$. Equations are usually referred to as (*), but you can also use *. As you can see, references are even turned into hyperlinks, which you can use externally as well, e.g. like this. Note that you can also reference labels in other posts as long as they appear on the same site, which is especially useful when referring to a question with multiple equations, or when commenting on a post. Due to a bug blocks containing a \label will break in preview, as a workaround you can put $\def\label#1{}$ in your post while editing and remove that on submission - unfortunately this means you won't spot misspelled references before submitting... Just don't forget to remove that \def again share answered  Oct 31 '13 at 10:21 community wiki Tobias Kienzler

3   Also works in comments: \eqref{*} yields a clickable (*) –  Tobias Kienzler  Oct 31 '13 at 10:22 To enable automatically tagging your queations with incremental numbers, add <script type="text/x-mathjax-config"> MathJax.Hub.Config({TeX: { equationNumbers: {autoNumber: "all"} }}); </script> to your header. –  Gerald Senarclens de Grancy  Jan 20 at 20:56 @GeraldSenarclensdeGrancy That would however yield a global numbering on all answers to one question, not per-answer. And it would break the current expectation of by default not having tags despite using unstarred \begin{align} etc.... Though personally I'd agree with this –  Tobias Kienzler  Jan 21 at 7:19 add a comment  |

up vote  36  down vote

Using \newcommand I would like to remark that it is possible to define LaTeX commands as you do in your TeX files. I felt so happy when I first discovered it! It's enough to insert something like $ \newcommand{\SES}[3]{ 0 \to #1 \to #2 \to #3 \to 0 } $  at the top of your post (remember the dollars!). Then you can just use your commands as you are used to do: in my example typing $$ \SES{A}{B}{C} $$will produce the following: 0→A→B→C→0 It's also possible to use plain \def: \def\ses#1#2#3{0 \to #1 \to #2 \to #3 \to 0} and then $\ses{A}{B}{C}$ will produce the same output. share edited Feb 12 '15 at 12:43 community wiki 3 revs, 3 users 67% Abramo

2   Be aware that this affects the entire post, possibly even the frontpage, so it should be used with great care. –  AlexR  Feb 21 '15 at 20:55 add a comment  |

up vote  34 down vote

Commutative diagrams AMScd diagrams must start with a "require": $\require{AMScd}$ \begin{CD} A @>a>> B\\ @V b V V= @VV c V\\ C @>>d> D \end{CD} to get this diagram: Aa→Bb↓=↓cC→dD @>>> is used for arrow right @<<< is used for arrow left @VVV is used for arrow down @AAA is used for arrow up @= is used for horizontal double line @| is used for vertical double line @. is used for no arrow Another example: \begin{CD} A @>>> B @>{\text{very long label}}>> C \\ @. @AAA @| \\ D @= E @<<< F \end{CD} A→Bvery long label→C↑∥D=E←F Long labels increase the length of the arrow and in this version also automatically increase corresponding arrows. $\require{AMScd}$ \begin{CD} RCOHR'SO_3Na @>{\text{Hydrolysis,$\Delta, Dil.HCl$}}>> (RCOR')+NaCl+SO_2+ H_2O \end{CD} RCOHR′SO3NaHydrolysis,Δ,Dil.HCl→(RCOR′)+NaCl+SO2+H2O share edited Feb 4 at 15:04 community wiki 9 revs, 4 users 68% Lehs

\begin{CD}  RCOHR'SO_3Na @>{\text{Hydrolysis,\Delta, Dil.HCl}>> (RCOR')+NaCl+SO_2+ H_2O \end{CD} Why does this code not give the correct output? –  Quark  Feb 4 at 10:04 @Quark: The main error was a missing bracket after HCl. –  Lehs  Feb 4 at 11:38 @Lehs Thanks. That was a silly mistake :| What if I wanted to write something below the arrow? Also, could you suggest some online website to learn MathJax? –  Quark  Feb 4 at 11:58 @Quark: then you move a > sign: @>>{\text{very long label}}> I learn MathJax from the examples i.e. in this tread. –  Lehs  Feb 4 at 15:06 @Lehs Why did you rollback my edit...? You removed the formatting from the list, broke again (in Chrome) the example diagram, and reinserted your duplicate example. Why? –  Najib Idrissi  Feb 4 at 15:25 @NajibIdrissi: because your edit appeared as a mess in IE. The diagram wasn't even written out. Maybe there is something wrong in your or in my web-program. Now it looks good in IE. –  Lehs  Feb 4 at 15:44 @NajibIdrissi: Now it also looks good in Chrome for Windows and for Android, plus Safari for Androids. I don't know what the problem is with the current version. –  Lehs  Feb 4 at 15:56 add a comment  |

up vote  33 down vote

Big braces Use \left and \right to make braces - (round), [square] and {curly} - scale up to be the size of their arguments. Thus $$ f\left( \left[ \frac{ 1+\left\{x,y\right\} }{ \left( \frac{x}{y}+\frac{y}{x} \right) \left(u+1\right) }+a \right]^{3/2} \right) $$ renders asf([1+{x,y}(xy+yx)(u+1)+a]3/2). Note that curly braces need to be escaped as \{ \}. If you start a big brace with \left and then need to match that to a \right brace that's on a different line, use the forms \right. and \left. to make "shadow" braces. Thus, $$ \begin{aligned} a=&\left(1+2+3+ \cdots \right. \\ & \cdots+ \left. \infty-2+\infty-1+\infty\right) \end{aligned} $$ renders asa=(1+2+3+⋯⋯+∞−2+∞−1+∞). There is also a \middle construct which is useful when one has a mid-expression brace which must also scale up: $$ \left\langle q \middle\| \frac{\frac{x}{y}}{\frac{u}{v}} \middle| p \right\rangle $$ renders as⟨q∥xyuv|p⟩. Note that constructs like \left\langle, \left| and \left\| are also possible. share answered  Oct 25 '13 at 17:47 community wiki E.P.

Note: \Big( ... \Big) produces (…) but this bracket size is fixed in all situations unlike \left( ... \right) which varies in size with its contents. \Big can be useful in various situations. –  Nick  Dec 19 '14 at 6:34 add a comment  |

up vote 28 down vote

Arbitrary operators If an operator is not available as a built-in command, use \operatorname{…}. So for things likearsinh(x) write  \operatorname{arsinh}(x) since  \arsinh(x) will give an error and  arsinh(x) has wrong font and spacing:  arsinh(x) . This was already mentioned in a comment by Charles Staats. You might consider this an addition to the FAQ section on \lim, \sin and so on. For operators which need limits above and below the operator, use \operatorname*{…}, as inResz=1(1z2−z)=1 share edited Sep 16 '15 at 3:13 community wiki 2 revs, 2 users 62% MvG

We can also use {\rm ...}. For example, {\rm arsinh} yields arsinh. –  Felix Marin  Aug 12 '14 at 0:27 8   @Felix: \rm will change the font but not the spacing. \operatorname{arsinh}x renders as “arsinhx” while {\rm arsinh}x renders as “arsinhx”. Notice the added space between operator and operand in the first example, which is missing in the second. On the whole, I'd say that operatorname is a lot more in the spirit of semantic markup, declaring what you want to write instead of how you want to write it, so I'd strongly suggest using this. –  MvG  Aug 13 '14 at 11:27 3   Thanks. I didn't know there was a difference between them. I always avoided operatorname because it was too long. –  Felix Marin  Aug 13 '14 at 14:41 1   Thanks for this. I thought carefully about whether to put \operatorname in the main post, and decided to leave it out. The reason is simple: If a beginner omits \operatorname, the resulting formula will still be perfectly clear, and a more experienced user will have no trouble inserting the\operatorname where it is needed. So including it in the main post would not be a good use of space. –  MJD  Aug 16 '14 at 6:28 1   ... I always use "\text{operator }". Hmmm, arsinh x vs arsinhx. –  Jp McCarthy  Feb 10 '15 at 16:48 If you use the same operator many times, I think you can do \DeclareMathOperator{\arsinh}{arsinh} at the post's top. Never tried it though… –  MickG  Aug 15 '15 at 17:28 add a comment  |

up vote 26 down vote

Limits To make a limit (like limx→1x2−1x−1), use this syntax:  First, start off with $\lim. This renders as lim. The backslash is there to prevent things like lim, where the letters are slanted.  Second, add \limits_{x \to 1} inside. The code now looks like $\lim \limits_{x \to 1}$, and renders as limx→1. The \to inside makes the right arrow, rendered as →. The_ makes the x→1 go underneath the lim. Finally, the pair of curly braces { } makes sure that x→1 is treated as a whole object, and not two separate things. Lastly, add the function you want to apply the limit to. To make the limit mentioned above, limx→1x2−1x−1, simply use $\lim\limits_{x \to 1} \frac{x^2-1}{x-1}$.  And that is how you make a limit using MathJax. share edited Jul 17 '14 at 12:25 community wiki 2 revs, 2 users 94% JChau

9   Why not just \lim_{x\to 1}limx→1? As I understand it  \limits is only needed for operations that don't already understand limits, for example if you want to use  + and get k+i=1 instead of +ki=1 When used inline, your suggestion will produce  limx→1  instead of the more compact form  limx→1  that mathjax normally chooses. Are you sure this is good advice? –  MJD  Feb 26 '14 at 14:10 @MJD $\lim_{x\to 1} renders to limx→1, and $\lim\limits_{x\to 1 renders as lim\limits_{x\to 1}. Note how the x→1 is separated from the first limit, and not directly underneath. We do not write limits like that in real life, so we use \limits. –  JChau  Feb 26 '14 at 16:19 I meant that the second limit renders to limx→1 –  JChau  Feb 26 '14 at 16:28 6   Limits are usually written that way in typeset materials like papers and books when the limit is inline, rather than a displayed formula, and that's why MathJax typesets it that way. –  MJD  Feb 26 '14 at 16:41 4   The issue with this answer is that it is trying to "force" display mode on inline code. Doing so makes the text look less pretty. For example, see how the spacing between the lines change when I force display mode using \lim\limits_{x\mapsto 1}\dfrac1x: limx↦11x. On the other hand, when I let TEX do what it wants to do, using \lim_{x\mapsto 1}\frac1x, the spacing between the lines stays the same, which is much neater: limx↦11x. This is much easier on the eyes. If you want to make your math mode more prominent then take a new line using $$-$$ –  user1729  Jul 17 '14 at 12:30 2   The moral is: TEX was written by a jolly clever chap. Let it do what it wants, because it does it for a reason! –  user1729  Jul 17 '14 at 12:35 Part 11 of the "question" shows how to write limits in the way they were meant to be written in LaTeX and MathJax. –  David K  Nov 14 '15 at 23:17 add a comment  |

up vote 18  down vote

Absolute values and norms The absolute value of some expression can be denoted as \lvert x\rvert or, more generally, as \left\lvert … \right\rvert. It renders as ∣x∣. The norm of a vector (or similar) can be denoted as \lVert v\rVert or, more generally, as \left\lVert … \right\rVert. It renders as ∥v∥. (You may also write\left\|…\right\| instead.) In both cases, the rendering is better than what you'd get from |x| or ||v||, which render with bars that don't descend low enough and sub-optimal spacing. At least on some browsers, so here is a screenshot how it looks for me, using Firefox 31 on OS X: And here is the same formula rendered by your browser: |x|,||v||⟶∣x∣,∥v∥ It was typeset as $$|x|, ||v|| \quad\longrightarrow\quad \lvert x\rvert, \lVert v\rVert$$ share edited Aug 13 '14 at 11:59 community wiki 4 revs, 3 users 89% MvG

4   You can use \|x\| instead of \lVert x \rVert; ∥x∥ and ∥x∥. (I don't think that there is a difference between them. I've tried [asking on SE](tex.stackexchange.com/questions/77767/whats-the-correct-way-to-write-norm).) –  Martin Sleziak  Jun 24 '14 at 8:48 On my browser |x| and \lvert x\rvert (|x| and ∣x∣) look identical, contrary to your claim. Perhaps you need to show an example more complicated than just 'x'? –  MJD  Jun 24 '14 at 12:39 @MJD: What's your browser? I included a screenshot to support my claim. –  MvG  Aug 13 '14 at 11:24 Usually various versions of Firefox on either Linux or Windows. I happen to have Windows 8 booted now, so here's a screenshot from there:a.pomf.se/jrujkq.PNG The bar height looks good on both pairs of symbols; the spacing is a little off for the || version. On Linux they looked the same. –  MJD  Aug 13 '14 at 17:02 Here's a screenshot with FF 31.0 under Linux: a.pomf.se/fhwmjo.png –  MJD  Aug 16 '14 at 6:23 add a comment  |

up vote  16  down vote

Left and Right Implication Arrows Another way to display the arrows for right and left implication instead of using $\Rightarrow$, $\Leftarrow$ and $\Leftrightarrow$ which produces ⇒, ⇐ and ⇔ respectively, you can use $\implies$ for ⟹, $\impliedby$ for ⟸ and $\iff$ for ⟺ The latter of which produces longer arrows which may be more desirable to some. share edited May 6 '14 at 22:15 community wiki 3 revs, 2 users 74% jnh

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up vote  9  down vote

Long division $$ \require{enclose} \begin{array}{r} 13 \\[-3pt] 4 \enclose{longdiv}{52} \\[-3pt] \underline{4}\phantom{2} \\[-3pt] 12 \\[-3pt] \underline{12} \end{array} $$ 134524_1212_ One important trick shown here is the use of \phantom{2} to make a blank space that is the same size and shape as the digit 2 just above it. This is adapted from http://stackoverflow.com/a/22871404/3466415 (which uses slightly different but not less valid formatting). share edited Jul 27 '15 at 20:19 community wiki 5 revs, 3 users 93% David K

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up vote 8 down vote

The degree symbol for angles is not ^\circ. Although many people use this notation, the result looks quite different from the canonical degree symbol shipped with the font: 90° renders as 90° while 90^\circ renders as 90∘. If your keyboard doesn't have a ° key, feel free to copy from this post here, or follow these suggestions. Note that comments below indicate that on some configurations at least, ° renders inferior to ^\circ. And I recently had a post of mine edited just for the sake of turning ° into ^\circ, indicating that someone felt rather strongly about this. So the suggestion above does seem somewhat controversial at the moment. I maintain that from a semantic point of view, ° is superior to ^\circ, and if the rendering suffers from this, then it's a bug in MathJax. After all, LaTeX offers a proper degree symbol in the tex companion fonts, indicating that someone there, too, decided that ^\circ is not perfect. But if things are broken now, I can't fault people from pragmatically sticking with the rendering they prefer. Personally I prefer semantics, also for the sake of screen readers. share edited Jul 12 '15 at 6:28 community wiki 3 revs, 2 users 91% MvG

If mathjax loads siunitx or gensymb, there is then \degree in latex which is the degree symbol. –  dustin  Feb 17 '15 at 22:29 @dustin: I couldn't find siunitx or gensymb mentioned anywhere in the MatJax source repository. Are they available as some kind of third-party extension? If so, where? Since MathJax is not LaTeX, packages can't be loaded unless they have been migrated. By the way, all occurrences of “degree” in the MathJax sources refer to something else, as far as I can tell, so there really doesn't seem to be a \degree macro. There should be one, imho. –  MvG  Feb 17 '15 at 23:39 I am not a mathjax expert. I just know latex. I just gave that suggestion in case they were available. Siunitx would be a great package to have. If you aren't familiar, you will see the advantage by scanning the documentation on ctan. –  dustin  Feb 17 '15 at 23:43 7   On my display, ° looks bad and ^\circ looks good: a.pomf.se/xnlfyg.png –  MJD  Mar 24 '15 at 21:10 add a comment  |

up vote  8  down vote	To highlight an equation, \bbox can be used. E.g, $$ \bbox[yellow] { e^x=\lim_{n\to\infty} \left( 1+\frac{x}{n} \right)^n \qquad (1) } $$ produces ex=limn→∞(1+xn)n(1) or $$ \bbox[border:2px solid red] { e^x=\lim_{n\to\infty} \left( 1+\frac{x}{n} \right)^n \qquad (2) } $$ produces ex=limn→∞(1+xn)n(2) share edited Jan 10 at 20:02 community wiki 2 revs webbertiger
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up vote  8  down vote	Giving reasons on each line of a sequence of equations To produce this:v+w=0Given−w=−w+0additive identity−w+0=−w+(v+w)equations (1) and (2) write this: \begin{align} v + w & = 0 &&\text{Given} \tag 1\\ -w & = -w + 0 && \text{additive identity} \tag 2\\ -w + 0 & = -w + (v + w) && \text{equations $(1)$ and $(2)$} \end{align} share edited Feb 15 at 18:33 community wiki 2 revs David K
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up vote  4  down vote

Pack of cards If you are asking (or answering) a combinatorics question involving packs of cards you can make it look more elegant by using \spadesuit, \heartsuit,\diamondsuit, \clubsuit in math mode:♠♡♢♣ Or if you're really fussy: \color{red}{\heartsuit} and  \color{red}{\diamondsuit} ♡♢ share edited Feb 1 at 13:10 community wiki 2 revs, 2 users 83% David