MathJax 基础教程

Greek letters

Formula	Symbol	Formula	Symbol	Formula	Symbol	Formula	Symbol
\alpha	α	\Alpha	A	\nu	ν	\Nu	N
\beta	β	\Beta	B	\xi	ξ	\Xi	Ξ
\gamma	γ	\Gamma	Γ	\omicron	ο	\Omicron	O
\delta	δ	\Delta	Δ	\pi	π	\Pi	Π
\epsilon \varepsilon	ϵ ε	\Epsilon	E	\rho \varrho	ρ ϱ	\Rho	R
\zeta	ζ	\Zeta	Z	\sigma \varsigma	σ ς	\Sigma	Σ
\eta	η	\eta	H	\tau	τ	\Tau	T
\theta \vartheta	θ ϑ	\Theta	Θ	\upsilon	υ	\Upsilon	Υ
\iota	ι	\Iota	I	\phi \varphi	ϕ φ	\Phi	Φ
\kappa	κ	\Kappa	K	\chi	χ	\Chi	X
\lambda	λ	\Lambda	Λ	\psi	ψ	\Psi	Ψ
\mu	μ	\Mu	M	\omega	ω	\Omega	Ω

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.

Superscripts & Subscripts

use

^

for superscripts and

_

for subscripts.

x_i^2

is x2i

Groups

use

{

and

}

.

10^10

is 1010,

10^{10}

is 1010

Parentheses

Formula	Symbol	Formula	Symbol
(	(	)	)
[	[	]	]
\{	{	\{	}
|	|	|	|
\langle	⟨	\rangle	⟩
\lceil	⌈	\rceil	⌉
\lfloor	⌊	\rfloor	⌋

These do not scale with the formula in between, so if you write

(\frac12)

the parentheses will be too small:(12). Using

\left(

…

\right)

will make the sizes adjust automatically to the formula they enclose:

\left(\frac12\right)

is (12).

There are also invisible parentheses, denoted by

.

:

\left.\frac12\right\rbrace

is 12}.

Fractions

\frac ab

applies to the next two groups, and produces ab.And

\frac{a+1}{b+1}

is a+1b+1.

For more complicated, use

\over

,

{a+1\over b+1}

is a+1b+1.

Sums and integrals

Formula	Symbol	Formula	Symbol
\int	∫	\iint	∬
\prod	∏	\sum	∑
\bigcup	⋃	\bigcap	⋂

The subscript is the lower limit and the superscript is the upper limit, so for example

\sum_1^n

is ∑n1;

\sum_{i=0}^\infty i^2

is ∑∞i=0i2.

Radical signs

Use sqrt, which adjusts to the size of its argument:

\sqrt{x^3}

is x3−−√;

\sqrt[3]{\frac xy}

is xy−−√3.

For complicated expressions, consider using

{...}^{1/2}

instead, for example

{\left(\frac 13\right)}^{\frac 12}

is (ab)12.

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

Special symbols and Notations

Some of the most common include:

\lt

<

\gt

>

\le

≤

\ge

≥

\neq

≠.

\not\lt

≮(not recommended).

\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

ℵ

\nabla

∇

\partial

∂

\Im

I`\Re` R

For modular equivalence, use

\pmod

like this:

a\equiv b\pmod n

a≡b(modn)

a_1, a_2, \ldots ,a_n

a1,a2,…,an;

a_1+a_2+\cdots+a_n

a1+a2+⋯+an

Script lowercase l is

\ell

ℓ

Spaces

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.

Text

Use

\text{…}

,

\{x\in s\mid x\text{ is extra large}\}

is {x∈s∣x is extra large}

Accents and diacritical marks

\hat x

x^,

\widehat{xy}

xyˆ,

\bar x

x¯,

\overline{xyz}

xyz¯¯¯¯¯,

\vec

, x⃗ ,

\overrightarrow

xy−→

\overleftrightarrow

xyz←→,

\frac d{dx}x\dot x =  \dot x^2 +  x\ddot x

ddxxx˙=x˙2+xx¨