求和的公式表達(dá)

內(nèi)嵌公式岂膳，使用$...$. 單獨(dú)展示的一行使用 $$...$$.
渲染的差別望伦，比如

會(huì)顯示 (內(nèi)嵌模式) ，而下面這樣

為獨(dú)立的一塊渲染區(qū)域恕出，它是居中展示的，字體也要更大一些

符號

希臘字母,
\alpha, \beta, …, \omega: .

大寫,
\Gamma, \Delta, …, \Omega: .

上標(biāo)和下標(biāo),
use ^ and _. For example, x_i^2: , \log_2 x: .

分組
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: .
But 10^{10} gives what you probably wanted: .
Use curly braces to delimit a formula to which a superscript or subscript applies: x⁵6 is an error;
{x^y}z is , and x^{yz} is . Observe the difference between x_i^2 and x_{i^2} .

Parentheses(圓括號)
一般的()[]筷登， . 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: (x√y3)

. Using \left(…\right) will make the sizes adjust automatically to the formula they enclose: .

\left and \right apply to all the following sorts of parentheses:

synbol	means
( and )
[ and ]
\{ and \}
|
\vert , \Vert	有問題剃根，可能需要在其他的語境下才生效
\langle and \rangle
\lceil and \rceil
\lfloor and \rfloor

. \middle can be used to add additional dividers. There are also invisible parentheses, denoted by . :
\left. \frac12\right\rbrace is .

If manual size adjustments are required: \Biggl(\biggl(\Bigl(\bigl((x)\bigr)\Bigr)\biggr)\Biggr) gives .
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 . Don't forget {…} if the limits are more than a single symbol.
For example, \sum_{i=0}^\infty i^2 is
.
Similarly,

symbol	redered as
\prod
\int
\bigcup
\bigcap
\iint
\iiint
\idotsint

.

Fractions There are three ways to make these. \frac ab applies to the next two groups, and produces ;
for more complicated numerators and denominators use {…}: \frac{a+1}{b+1} is .
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 .
Using \cfrac{a} command is useful for continued fractions , more details for which are given in this sub-article.

Fonts
Use \mathbb or \Bbb for "blackboard bold": ??????

symbols	for	redered as
\mathbb or \Bbb	blackboard bold
\mathbf	boldface
\mathit	italics	,
\pmb	boldfaced italics
\mathtt	typewriter
\mathrm	roman
\mathsf	sans-serif
\mathcal	calligraphic letters
\mathscr	script letters
\mathfrak	Fraktur (old German style) letters

• Radical signs Use sqrt,
  which adjusts to the size of its argument:\sqrt{x^3} x3 means: ;
  \sqrt[3]{\frac xy} means: .
  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: , not sin x : .
  Use subscripts to attach a notation to \lim: \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:

symbols	redered as
\lt \gt \le \leq \leqq \leqslant \ge \geq \geqq \geqslant \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
\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 \lhd \therefore
\infty \aleph_0
\nabla \partial

• For modular equivalence, use \pmod like this: a\equiv b\pmod n .

• \ldots is the dots in a1,a2,…,an

• \cdots is the dots in a1+a2+?+an

• Some Greek letters have variant forms:
  \epsilon \varepsilon: ,
  \phi \varphi: ,
  and others.
  Script lowercase l is \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.