Including equations with TeX formatting is now supported on this forum. Details below, copied from math.stackexchange.com.
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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.)
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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 \sum_{i=0}^n i^2 = \frac{(n^2+n)(2n+1)}{6} (which is inline mode) or type$$ \sum_{i=0}^n i^2 = \frac{(n^2+n)(2n+1)}{6} $$to show
\sum_{i=0}^n i^2 = \frac{(n^2+n)(2n+1)}{6}(which is display mode).
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For Greek letters, use
\alpha,\beta, …,\omega: \alpha, \beta, … \omega. For uppercase, use\Gamma,\Delta, …,\Omega: \Gamma, \Delta, …, \Omega. -
For superscripts and subscripts, use
^and_. For example,x_i^2: x_i^2,\log_2 x: \log_2 x. -
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 do10^10, you will get a surprise: 10^10. But10^{10}gives what you probably wanted: 10^{10}. Use curly braces to delimit a formula to which a superscript or subscript applies:x^5^6is an error;{x^y}^zis {x^y}^z, andx^{y^z}is x^{y^z}. Observe the difference betweenx_i^2x_i^2 andx_{i^2}x_{i^2}. -
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: (\frac{\sqrt x}{y^3}). Using\left(…\right)will make the sizes adjust automatically to the formula they enclose:\left(\frac{\sqrt x}{y^3}\right)is \left(\frac{\sqrt x}{y^3}\right).\leftand\rightapply to all the following sorts of parentheses:(and)(x),[and][x],\{and\}\{ x \},||x|,\vert\vert x \vert,\Vert\Vert x \Vert,\langleand\rangle\langle x \rangle,\lceiland\rceil\lceil x \rceil, and\lfloorand\rfloor\lfloor x \rfloor. There are also invisible parentheses, denoted by.:\left.\frac12\right\rbraceis \left.\frac12\right\rbrace. -
Sums and integrals
\sumand\int; the subscript is the lower limit and the superscript is the upper limit, so for example\sum_1^n\sum_1^n. Don’t forget{…}if the limits are more than a single symbol. For example,\sum_{i=0}^\infty i^2is \sum_{i=0}^\infty i^2. Similarly,\prod\prod,\int\int,\bigcup\bigcup,\bigcap\bigcap,\iint\iint. -
Fractions There are two ways to make these.
\frac abapplies to the next two groups, and produces \frac ab; for more complicated numerators and denominators use{…}:\frac{a+1}{b+1}is \frac{a+1}{b+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+1\over b+1}. -
Fonts
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\mathbbor\Bbbfor “blackboard bold”: \mathbb{CHNQRZ}. - Use
\mathbffor boldface: \mathbf{ABCDEFGHIJKLMNOPQRSTUVWXYZ} \mathbf{abcdefghijklmnopqrstuvwxyz}. - Use
\mathttfor “typewriter” font: \mathtt{ABCDEFGHIJKLMNOPQRSTUVWXYZ} \mathtt{abcdefghijklmnopqrstuvwxyz}. - Use
\mathrmfor roman font: \mathrm{ABCDEFGHIJKLMNOPQRSTUVWXYZ} \mathrm{abcdefghijklmnopqrstuvwxyz}. - Use
\mathsffor sans-serif font: \mathsf{ABCDEFGHIJKLMNOPQRSTUVWXYZ} \mathsf{abcdefghijklmnopqrstuvwxyz}. - Use
\mathcalfor “calligraphic” letters: \mathcal{ ABCDEFGHIJKLMNOPQRSTUVWXYZ} - Use
\mathscrfor script letters: \mathscr{ABCDEFGHIJKLMNOPQRSTUVWXYZ} - Use
\mathfrakfor “Fraktur” (old German style) letters: \mathfrak{ABCDEFGHIJKLMNOPQRSTUVWXYZ} \mathfrak{abcdefghijklmnopqrstuvwxyz}.
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Radical signs Use
sqrt, which adjusts to the size of its argument:\sqrt{x^3}\sqrt{x^3};\sqrt[3]{\frac xy}\sqrt[3]{\frac 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\sin x, notsin xsin x. Use subscripts to attach a notation to\lim:\lim_{x\to 0}\lim_{x\to 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:
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\lt \gt \le \ge \neq\lt\, \gt\, \le\, \ge\, \neq. You can use\notto put a slash through almost anything:\not\lt\not\lt but it often looks bad. -
\times \div \pm \mp\times\, \div\, \pm\, \mp.\cdotis a centered dot: x\cdot y -
\cup \cap \setminus \subset \subseteq \subsetneq \supset \in \notin \emptyset \varnothing\cup\, \cap\, \setminus\, \subset\, \subseteq \,\subsetneq \,\supset\, \in\, \notin\, \emptyset\, \varnothing -
{n+1 \choose 2k}or\binom{n+1}{2k}{n+1 \choose 2k} -
\to \rightarrow \leftarrow \Rightarrow \Leftarrow \mapsto\to\, \rightarrow\, \leftarrow\, \Rightarrow\, \Leftarrow\, \mapsto -
\land \lor \lnot \forall \exists \top \bot \vdash \vDash\land\, \lor\, \lnot\, \forall\, \exists\, \top\, \bot\, \vdash\, \vDash -
\star \ast \oplus \circ \bullet\star\, \ast\, \oplus\, \circ\, \bullet -
\approx \sim \simeq \cong \equiv \prec \lhd\approx\, \sim \, \simeq\, \cong\, \equiv\, \prec, \lhd. -
\infty \aleph_0\infty\, \aleph_0\nabla \partial\nabla\, \partial\Im \Re\Im\, \Re - For modular equivalence, use
\pmodlike this:a\equiv b\pmod na\equiv b\pmod n. -
\ldotsis the dots in a_1, a_2, \ldots ,a_n\cdotsis the dots in a_1+a_2+\cdots+a_n - Some Greek letters have variant forms:
\epsilon \varepsilon\epsilon\, \varepsilon,\phi \varphi\phi\, \varphi, and others. Script lowercase l is\ell\ell. - 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.
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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␣banda␣␣␣␣bare both a b. To add more space, use\,for a thin space a\,b;\;for a wider space a\;b.\quadand\qquadare large spaces: a\quad b, a\qquad b.To set plain text, use
\text{…}: \{x\in s\mid x\text{ is extra large}\}. You can nest$…$inside of\text{…}. -
Accents and diacritical marks Use
\hatfor a single symbol \hat x,\widehatfor a larger formula \widehat{xy}. If you make it too wide, it will look silly. Similarly, there are\bar\bar x and\overline\overline{xyz}, and\vec\vec x and\overrightarrow\overrightarrow{xy} and\overleftrightarrow\overleftrightarrow{xy}. For dots, as in \frac d{dx}x\dot x = \dot x^2 + x\ddot x, use\dotand\ddot. -
Special characters used for MathJax interpreting can be escaped using the \ character:
\$\$,\{\{,\_\_, etc. If you want \ itself, you should use\backslash\backslash, because\\is for a new line.