求和的公式表达
内嵌公式,使用$...$
. 单独展示的一行使用 $$...$$
.
渲染的差别,比如
会显示 (内嵌模式) ,而下面这样
为独立的一块渲染区域,它是居中展示的,字体也要更大一些
符号
希腊字母,
\alpha, \beta, …, \omega
: .
大写,
\Gamma, \Delta, …, \Omega
: .
上标和下标,
use ^ and _. For example, x_i^2
: , \log_2 x
: .
分组
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;
{xy}z is , and x{yz} is . Observe the difference between x_i^2 and x_{i^2} .
Parentheses(圆括号)
一般的()[], . 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 |
有问题,可能需要在其他的语境下才生效 |
\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}{b}
command is useful for continued fractions , more details for which are given in this sub-article.
Fonts
Use \mathbb or \Bbb for "blackboard bold": ℂℍℕℚℝℤ
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
: , notsin 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+⋯+anSome 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.