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参考维基百科的数学公式教程
参考Cmd Markdown 公式指导手册

本文为 MathJax 在 Markdown 环境下的语法指引。

如何插入公式

\(\LaTeX\) 的数学公式有两种:行中公式和独立公式(行间公式)。行中公式放在文中与其它文字混编,独立公式单独成行。

行中公式可以用如下方法表示:

$ 数学公式 $

独立公式可以用如下方法表示:

$$ 数学公式 $$

函数、符号及特殊字符

声调 / 变音符号

\dot{a}, \ddot{a}, \acute{a}, \grave{a}

\({\displaystyle {\dot {a}},{\ddot {a}},{\acute {a}},{\grave {a}}}\)

\check{a}, \breve{a}, \tilde{a}, \bar{a}

\({\displaystyle {\check {a}},{\breve {a}},{\tilde {a}},{\bar {a}}}\)

\hat{a}, \widehat{a}, \vec{a}

\({\displaystyle {\hat {a}},{\widehat {a}},{\vec {a}}}\)

标准函数

指数

\exp_a b = a^b, \exp b = e^b, 10^m

\({\displaystyle \exp _{a}b=a^{b},\exp b=e^{b},10^{m}}\)

对数

\ln c, \lg d = \log e, \log_{10} f

\({\displaystyle \ln c,\lg d=\log e,\log _{10}f}\)

三角函数

\sin a, \cos b, \tan c, \cot d, \sec e, \csc f

\({\displaystyle \sin a,\cos b,\tan c,\cot d,\sec e,\csc f}\)

\arcsin a, \arccos b, \arctan c

\({\displaystyle \arcsin a,\arccos b,\arctan c}\)

\arccot d, \arcsec e, \arccsc f

\({\displaystyle \operatorname {arccot} d,\operatorname {arcsec} e,\operatorname {arccsc} f}\)

\sinh a, \cosh b, \tanh c, \coth d

\({\displaystyle \sinh a,\cosh b,\tanh c,\coth d}\)

\operatorname{sh}k, \operatorname{ch}l, \operatorname{th}m, \operatorname{coth}n

\({\displaystyle \operatorname {sh} k,\operatorname {ch} l,\operatorname {th} m,\operatorname {coth} n}\)

\operatorname{argsh}o, \operatorname{argch}p, \operatorname{argth}q

\({\displaystyle \operatorname {argsh} o,\operatorname {argch} p,\operatorname {argth} q}\)

符号函数,绝对值

\sgn r, \left\vert s \right\vert

\({\displaystyle \operatorname {sgn} r,\left\vert s\right\vert }\)

最大值,最小值

\min(x,y), \max(x,y)

\({\displaystyle \min(x,y),\max(x,y)}\)

界限,极限

\min x, \max y, \inf s, \sup t

\({\displaystyle \min x,\max y,\inf s,\sup t}\)

\lim u, \liminf v, \limsup w

\({\displaystyle \lim u,\liminf v,\limsup w}\)

\lim_{x \to \infty} \frac{1}{n(n+1)}

\({\displaystyle \lim_{x \to \infty} \frac{1}{n(n+1)}}\)

\dim p, \deg q, \det m, \ker\phi

\({\displaystyle \dim p,\deg q,\det m,\ker \phi}\)

投射

\Pr j, \hom l, \lVert z \rVert, \arg z

\({\displaystyle \Pr j,\hom l,\lVert z\rVert ,\arg z}\)

微分及导数

dt, \mathrm{d}t, \partial t, \nabla\psi

\({\displaystyle dt,\mathrm {d} t,\partial t,\nabla \psi }\)

dy/dx, \mathrm{d}y/\mathrm{d}x, \frac{dy}{dx}, \frac{\mathrm{d}y}{\mathrm{d}x}, \frac{\partial^2}{\partial x_1\partial x_2}y

\({\displaystyle dy/dx,\mathrm {d} y/\mathrm {d} x,{\frac {dy}{dx}},{\frac {\mathrm {d} y}{\mathrm {d} x}},{\frac {\partial ^{2}}{\partial x_{1}\partial x_{2}}}y}\)

\prime, \backprime, f^\prime, f\', f\'\', f^{(3)}, \dot y, \ddot y

\({\displaystyle \prime ,\backprime ,f^{\prime},f\’,f\’\’,f^{(3)}\!,{\dot {y}},{\ddot {y}}}\)

类字母符号及常数

\infty, \aleph, \complement, \backepsilon, \eth, \Finv, \hbar

\({\displaystyle \infty ,\aleph ,\complement ,\backepsilon ,\eth ,\Finv ,\hbar}\)

\Im, \imath, \jmath, \Bbbk, \ell, \mho, \wp, \Re, \circledS

\({\displaystyle \Im ,\imath ,\jmath ,\Bbbk ,\ell ,\mho ,\wp ,\Re ,\circledS }\)

模运算

s_k \equiv 0 \pmod{m}

\({\displaystyle s_{k}\equiv 0{\pmod {m}}}\)

a \bmod b

\({\displaystyle a \bmod b}\)

\gcd(m, n), \operatorname{lcm}(m, n)

\({\displaystyle \gcd(m,n),\operatorname {lcm} (m,n)}\)

\mid, \nmid, \shortmid, \nshortmid

\({\displaystyle \mid ,\nmid ,\shortmid ,\nshortmid}\)

根号

\surd, \sqrt{2}, \sqrt[n]{}, \sqrt[3]{\frac{x^3+y^3}{2}}

\({\displaystyle \surd ,{\sqrt {2}},{\sqrt[{n}]{}},{\sqrt[{3}]{\frac {x^{3}+y^{3}}{2}}}}\)

运算符

+, -, \pm, \mp, \dotplus

\({\displaystyle +,-,\pm ,\mp ,\dotplus}\)

\times, \div, \divideontimes, /, \backslash

\({\displaystyle \times ,\div ,\divideontimes ,/,\backslash}\)

\cdot, * \ast, \star, \circ, \bullet

\({\displaystyle \cdot ,*\ast ,\star ,\circ ,\bullet}\)

\boxplus, \boxminus, \boxtimes, \boxdot

\({\displaystyle \boxplus ,\boxminus ,\boxtimes ,\boxdot}\)

\oplus, \ominus, \otimes, \oslash, \odot

\({\displaystyle \oplus ,\ominus ,\otimes ,\oslash ,\odot}\)

\circleddash, \circledcirc, \circledast

\({\displaystyle \circleddash ,\circledcirc ,\circledast}\)

\bigoplus, \bigotimes, \bigodot

\({\displaystyle \bigoplus ,\bigotimes ,\bigodot}\)

集合

\{ \}, \O \empty \emptyset, \varnothing

\({\displaystyle \{\},\emptyset \emptyset \emptyset ,\varnothing }\)

\in, \notin \not\in, \ni, \not\ni

\({\displaystyle \in ,\notin \not \in ,\ni ,\not \ni}\)

\cap, \Cap, \sqcap, \bigcap

\({\displaystyle \cap ,\Cap ,\sqcap ,\bigcap}\)

\cup, \Cup, \sqcup, \bigcup, \bigsqcup, \uplus, \biguplus

\({\displaystyle \cup ,\Cup ,\sqcup ,\bigcup ,\bigsqcup ,\uplus ,\biguplus}\)

\setminus, \smallsetminus, \times

\({\displaystyle \setminus ,\smallsetminus ,\times}\)

\subset, \Subset, \sqsubset

\({\displaystyle \subset ,\Subset ,\sqsubset}\)

\supset, \Supset, \sqsupset

\({\displaystyle \supset ,\Supset ,\sqsupset}\)

\subseteq, \nsubseteq, \subsetneq, \varsubsetneq, \sqsubseteq

\({\displaystyle \subseteq ,\nsubseteq ,\subsetneq ,\varsubsetneq ,\sqsubseteq}\)

\supseteq, \nsupseteq, \supsetneq, \varsupsetneq, \sqsupseteq

\({\displaystyle \supseteq ,\nsupseteq ,\supsetneq ,\varsupsetneq ,\sqsupseteq}\)

\subseteqq, \nsubseteqq, \subsetneqq, \varsubsetneqq

\({\displaystyle \subseteqq ,\nsubseteqq ,\subsetneqq ,\varsubsetneqq}\)

\supseteqq, \nsupseteqq, \supsetneqq, \varsupsetneqq

\({\displaystyle \supseteqq ,\nsupseteqq ,\supsetneqq ,\varsupsetneqq}\)

关系符号

=, \ne, \neq, \equiv, \not\equiv

\({\displaystyle =,\neq ,\neq ,\equiv ,\not \equiv}\)

\doteq, \doteqdot, \overset{\underset{\mathrm{def}}{}}{=}, :=

\({\displaystyle \doteq ,\doteqdot ,{\overset {\underset {\mathrm {def} }{}}{=}},:=}\)

\sim, \nsim, \backsim, \thicksim, \simeq, \backsimeq, \eqsim, \cong, \ncong

\({\displaystyle \sim ,\nsim ,\backsim ,\thicksim ,\simeq ,\backsimeq ,\eqsim ,\cong ,\ncong}\)

\approx, \thickapprox, \approxeq, \asymp, \propto, \varpropto

\({\displaystyle \approx ,\thickapprox ,\approxeq ,\asymp ,\propto ,\varpropto}\)

<, \nless, \ll, \not\ll, \lll, \not\lll, \lessdot

\({\displaystyle <,\nless ,\ll ,\not \ll ,\lll ,\not \lll ,\lessdot}\)

>, \ngtr, \gg, \not\gg, \ggg, \not\ggg, \gtrdot

\({\displaystyle>,\ngtr ,\gg ,\not \gg ,\ggg ,\not \ggg ,\gtrdot }\)

\le, \leq, \lneq, \leqq, \nleq, \nleqq, \lneqq, \lvertneqq

\({\displaystyle \leq ,\leq ,\lneq ,\leqq ,\nleq ,\nleqq ,\lneqq ,\lvertneqq}\)

\ge, \geq, \gneq, \geqq, \ngeq, \ngeqq, \gneqq, \gvertneqq

\({\displaystyle \geq ,\geq ,\gneq ,\geqq ,\ngeq ,\ngeqq ,\gneqq ,\gvertneqq}\)

\lessgtr, \lesseqgtr, \lesseqqgtr, \gtrless, \gtreqless, \gtreqqless

\({\displaystyle \lessgtr ,\lesseqgtr ,\lesseqqgtr ,\gtrless ,\gtreqless ,\gtreqqless}\)

\leqslant, \nleqslant, \eqslantless

\({\displaystyle \leqslant ,\nleqslant ,\eqslantless}\)

\geqslant, \ngeqslant, \eqslantgtr

\({\displaystyle \geqslant ,\ngeqslant ,\eqslantgtr}\)

\lesssim, \lnsim, \lessapprox, \lnapprox

\({\displaystyle \lesssim ,\lnsim ,\lessapprox ,\lnapprox}\)

\gtrsim, \gnsim, \gtrapprox, \gnapprox

\({\displaystyle \gtrsim ,\gnsim ,\gtrapprox ,\gnapprox}\)

\prec, \nprec, \preceq, \npreceq, \precneqq

\({\displaystyle \prec ,\nprec ,\preceq ,\npreceq ,\precneqq}\)

\succ, \nsucc, \succeq, \nsucceq, \succneqq

\({\displaystyle \succ ,\nsucc ,\succeq ,\nsucceq ,\succneqq}\)

\preccurlyeq, \curlyeqprec

\({\displaystyle \preccurlyeq ,\curlyeqprec}\)

\succcurlyeq, \curlyeqsucc

\({\displaystyle \succcurlyeq ,\curlyeqsucc}\)

\precsim, \precnsim, \precapprox, \precnapprox

\({\displaystyle \precsim ,\precnsim ,\precapprox ,\precnapprox}\)

\succsim, \succnsim, \succapprox, \succnapprox

\({\displaystyle \succsim ,\succnsim ,\succapprox ,\succnapprox}\)

几何符号

\parallel, \nparallel, \shortparallel, \nshortparallel

\({\displaystyle \parallel ,\nparallel ,\shortparallel ,\nshortparallel}\)

\perp, \angle, \sphericalangle, \measuredangle, 45^\circ

\({\displaystyle \perp ,\angle ,\sphericalangle ,\measuredangle ,45^{\circ}}\)

\Box, \blacksquare, \diamond, \Diamond \lozenge, \blacklozenge, \bigstar

\({\displaystyle \Box ,\blacksquare ,\diamond ,\Diamond \lozenge ,\blacklozenge ,\bigstar}\)

\bigcirc, \triangle, \bigtriangleup, \bigtriangledown

\({\displaystyle \bigcirc ,\triangle ,\bigtriangleup ,\bigtriangledown}\)

\vartriangle, \triangledown

\({\displaystyle \vartriangle ,\triangledown}\)

\blacktriangle, \blacktriangledown, \blacktriangleleft, \blacktriangleright

\({\displaystyle \blacktriangle ,\blacktriangledown ,\blacktriangleleft ,\blacktriangleright}\)

逻辑符号

\forall, \exists, \nexists

\({\displaystyle \forall ,\exists ,\nexists}\)

\therefore, \because, \And

\({\displaystyle \therefore ,\because ,\And}\)

\or \lor \vee, \curlyvee, \bigvee

\({\displaystyle \lor ,\lor ,\vee ,\curlyvee ,\bigvee}\)

\and \land \wedge, \curlywedge, \bigwedge

\({\displaystyle \land ,\land ,\wedge ,\curlywedge ,\bigwedge}\)

\bar{q}, \bar{abc}, \overline{q}, \overline{abc},

\lnot \neg, \not\operatorname{R}, \bot, \top

\({\displaystyle {\bar {q}},{\bar {abc}},{\overline {q}},{\overline {abc}},}\)

\({\displaystyle \lnot \neg ,\not \operatorname {R} ,\bot ,\top }\)

\vdash \dashv, \vDash, \Vdash, \models

\({\displaystyle \vdash ,\dashv ,\vDash ,\Vdash ,\models}\)

\Vvdash \nvdash \nVdash \nvDash \nVDash

\({\displaystyle \Vvdash ,\nvdash ,\nVdash ,\nvDash ,\nVDash}\)

\ulcorner \urcorner \llcorner \lrcorner

\({\displaystyle \ulcorner \urcorner \llcorner \lrcorner}\)

箭头

\Rrightarrow, \Lleftarrow

\({\displaystyle \Rrightarrow ,\Lleftarrow}\)

\Rightarrow, \nRightarrow, \Longrightarrow \implies

\({\displaystyle \Rightarrow ,\nRightarrow ,\Longrightarrow ,\implies}\)

\Leftarrow, \nLeftarrow, \Longleftarrow

\({\displaystyle \Leftarrow ,\nLeftarrow ,\Longleftarrow}\)

\Leftrightarrow, \nLeftrightarrow, \Longleftrightarrow \iff

\({\displaystyle \Leftrightarrow ,\nLeftrightarrow ,\Longleftrightarrow \iff}\)

\Uparrow, \Downarrow, \Updownarrow

\({\displaystyle \Uparrow ,\Downarrow ,\Updownarrow}\)

\rightarrow \to, \nrightarrow, \longrightarrow

\({\displaystyle \rightarrow \to ,\nrightarrow ,\longrightarrow}\)

\leftarrow \gets, \nleftarrow, \longleftarrow

\({\displaystyle \leftarrow \gets ,\nleftarrow ,\longleftarrow}\)

\leftrightarrow, \nleftrightarrow, \longleftrightarrow

\({\displaystyle \leftrightarrow ,\nleftrightarrow ,\longleftrightarrow}\)

\uparrow, \downarrow, \updownarrow

\({\displaystyle \uparrow ,\downarrow ,\updownarrow}\)

\nearrow, \swarrow, \nwarrow, \searrow

\({\displaystyle \nearrow ,\swarrow ,\nwarrow ,\searrow}\)

\mapsto, \longmapsto

\({\displaystyle \mapsto ,\longmapsto}\)

\rightharpoonup \rightharpoondown \leftharpoonup \leftharpoondown \upharpoonleft \upharpoonright \downharpoonleft \downharpoonright \rightleftharpoons \leftrightharpoons

\({\displaystyle \rightharpoonup ,\rightharpoondown ,\leftharpoonup ,\leftharpoondown ,\upharpoonleft ,\upharpoonright ,\downharpoonleft ,\downharpoonright ,\rightleftharpoons ,\leftrightharpoons}\)

\curvearrowleft \circlearrowleft \Lsh \upuparrows \rightrightarrows \rightleftarrows \rightarrowtail \looparrowright

\({\displaystyle \curvearrowleft ,\circlearrowleft ,\Lsh ,\upuparrows ,\rightrightarrows ,\rightleftarrows ,\rightarrowtail ,\looparrowright}\)

\curvearrowright \circlearrowright \Rsh \downdownarrows \leftleftarrows \leftrightarrows \leftarrowtail \looparrowleft

\({\displaystyle \curvearrowright ,\circlearrowright ,\Rsh ,\downdownarrows ,\leftleftarrows ,\leftrightarrows ,\leftarrowtail ,\looparrowleft}\)

\hookrightarrow \hookleftarrow \multimap \leftrightsquigarrow \rightsquigarrow \twoheadrightarrow \twoheadleftarrow

\({\displaystyle \hookrightarrow ,\hookleftarrow ,\multimap ,\leftrightsquigarrow ,\rightsquigarrow ,\twoheadrightarrow ,\twoheadleftarrow}\)

特殊符号

省略号:数学公式中常见的省略号有两种,\ldots 表示与文本底线对齐的省略号,\cdots 表示与文本中线对齐的省略号。

\amalg \% \dagger \ddagger \ldots \cdots

\({\displaystyle \amalg \%\dagger \ddagger \ldots \cdots}\)

\smile \frown \wr \triangleleft \triangleright

\({\displaystyle \smile \frown \wr \triangleleft \triangleright}\)

\diamondsuit, \heartsuit, \clubsuit, \spadesuit, \Game, \flat, \natural, \sharp

\({\displaystyle \diamondsuit ,\heartsuit ,\clubsuit ,\spadesuit ,\Game ,\flat ,\natural ,\sharp}\)

未分类

\diagup \diagdown \centerdot \ltimes \rtimes \leftthreetimes \rightthreetimes

\({\displaystyle \diagup ,\diagdown ,\centerdot ,\ltimes ,\rtimes ,\leftthreetimes ,\rightthreetimes}\)

\eqcirc \circeq \triangleq \bumpeq \Bumpeq \doteqdot \risingdotseq \fallingdotseq

\({\displaystyle \eqcirc ,\circeq ,\triangleq ,\bumpeq ,\Bumpeq ,\doteqdot ,\risingdotseq ,\fallingdotseq}\)

\intercal \barwedge \veebar \doublebarwedge \between \pitchfork

\({\displaystyle \intercal ,\barwedge ,\veebar ,\doublebarwedge ,\between ,\pitchfork}\)

\vartriangleleft \ntriangleleft \vartriangleright \ntriangleright

\({\displaystyle \vartriangleleft ,\ntriangleleft ,\vartriangleright ,\ntriangleright}\)

\trianglelefteq \ntrianglelefteq \trianglerighteq \ntrianglerighteq

\({\displaystyle \trianglelefteq ,\ntrianglelefteq ,\trianglerighteq ,\ntrianglerighteq}\)

关于这些符号的更多语义,参阅 TeX Cookbook 的简述。

上标、下标及积分等

功能|语法|效果

^ 表示上标, _ 表示下标。如果上下标的内容多于一个字符,需要用 {} 将这些内容括成一个整体。上下标可以嵌套,也可以同时使用。

上标

a^2

\({\displaystyle a^{2}}\)

下标

a_2

\({\displaystyle a_{2}}\)

组合

a^{2+2}

\({\displaystyle a^{2+2}}\)

a_{i,j}

\({\displaystyle a_{i,j}}\)

结合上下标

x_2^3

\({\displaystyle x_{2}^{3}}\)

前置上下标

{}_1^2\!X_3^4

\({\displaystyle {}_{1}^{2}\!X_{3}^{4}}\)

导数(HTML

x\'

\({\displaystyle x\’}\)

导数(PNG

x^\prime

\({\displaystyle x^{\prime}}\)

导数(错误

x\prime

\({\displaystyle x\prime}\)

导数点

\dot{x}

\({\displaystyle {\dot {x}}}\)

\ddot{y}

\({\displaystyle {\ddot {y}}}\)

向量

\vec{c}(只有一个字母)

\({\displaystyle {\vec {c}}}\)

\overleftarrow{a b}

\({\displaystyle {\overleftarrow {ab}}}\)

\overrightarrow{c d}

\({\displaystyle {\overrightarrow {cd}}}\)

\overleftrightarrow{a b}

\({\displaystyle {\overleftrightarrow {ab}}}\)

\widehat{e f g}

\({\displaystyle {\widehat {efg}}}\)

上弧

(注: 正确应该用 \overarc,但在这里行不通。要用建议的语法作为解决办法。)(使用 \ overarc 时需要引入 {arcs} 包。)

\overset{\frown} {AB}

\({\displaystyle {\overset {\frown}{AB}}}\)

上划线

\overline{h i j}

\({\displaystyle {\overline {hij}}}\)

下划线

\underline{k l m}

\({\displaystyle {\underline {klm}}}\)

上括号

\overbrace{1+2+\cdots+100}

\({\displaystyle \overbrace {1+2+\cdots +100} }\)

\begin{matrix} 5050 \\ \overbrace{ 1+2+\cdots+100 } \end{matrix}

\({\displaystyle {\begin{matrix}5050\\\overbrace {1+2+\cdots +100} \end{matrix}}}\)

下括号

\underbrace{a+b+\cdots+z}

\({\displaystyle \underbrace {a+b+\cdots +z} }\)

\begin{matrix} \underbrace{ a+b+\cdots+z } \\ 26 \end{matrix}

\({\displaystyle {\begin{matrix}\underbrace {a+b+\cdots +z} \\26\end{matrix}}}\)

求和(累加)

\sum_{k=1}^N k^2

\({\displaystyle \sum _{k=1}^{N}k^{2}}\)

\begin{matrix} \sum_{k=1}^N k^2 \end{matrix}

\({\displaystyle {\begin{matrix}\sum _{k=1}^{N}k^{2}\end{matrix}}}\)

求积(累乘)

\prod_{i=1}^N x_i

\({\displaystyle \prod _{i=1}^{N}x_{i}}\)

\begin{matrix} \prod_{i=1}^N x_i \end{matrix}

\({\displaystyle {\begin{matrix}\prod _{i=1}^{N}x_{i}\end{matrix}}}\)

上积

\coprod_{i=1}^N x_i

\({\displaystyle \coprod _{i=1}^{N}x_{i}}\)

\begin{matrix} \coprod_{i=1}^N x_i \end{matrix}

\({\displaystyle {\begin{matrix}\coprod _{i=1}^{N}x_{i}\end{matrix}}}\)

极限

\lim_{n \to \infty}x_n

\({\displaystyle \lim _{n\to \infty}x_{n}}\)

\begin{matrix} \lim_{n \to \infty}x_n \end{matrix}

\({\displaystyle {\begin{matrix}\lim _{n\to \infty }x_{n}\end{matrix}}}\)

积分

\int_{-N}^{N} e^x\, {\rm d}x

\({\displaystyle \int _{-N}^{N}e^{x}\,{\rm d} x}\)

本例中 \,{\rm d} 部分可省略,但建议加入,能使式子更美观。{\rm d}可以用\mathrm{d}等价替换。

\begin{matrix} \int_{-N}^{N} e^x\, \mathrm{d}x \end{matrix}(矩阵中积分符号变小)

\({\displaystyle {\begin{matrix}\int _{-N}^{N}e^{x}\,\mathrm {d} x\end{matrix}}}\)

双重积分

\iint_{D}^{W} \, \mathrm{d}x\,\mathrm{d}y

\({\displaystyle \iint _{D}^{W}\,\mathrm {d} x\,\mathrm {d} y}\)

三重积分

\iiint_{E}^{V} \, \mathrm{d}x\,\mathrm{d}y\,\mathrm{d}z

\({\displaystyle \iiint _{E}^{V}\,\mathrm {d} x\,\mathrm {d} y\,\mathrm {d} z}\)

闭合的曲线、曲面积分

\oint_{C} x^3\, \mathrm{d}x + 4y^2\, \mathrm{d}y

\({\displaystyle \oint _{C}x^{3}\,\mathrm {d} x+4y^{2}\,\mathrm {d} y}\)

交集

\bigcap_1^{n} p

\({\displaystyle \bigcap _{1}^{n}p}\)

并集

\bigcup_1^{k} p

\({\displaystyle \bigcup _{1}^{k}p}\)

分数

通常使用 \frac {分子} {分母} 命令产生一个分数,分数可嵌套。
便捷情况可直接输入 \frac ab 来快速生成一个 \(\frac ab\)
如果分式很复杂,亦可使用 分子 \over 分母 命令,此时分数仅有一层。

功能|语法|效果

分数

\frac{2}{4}=0.5

\({\displaystyle {\frac {2}{4}}=0.5}\)

小型分数

\tfrac{2}{4} = 0.5

\({\displaystyle {\tfrac {2}{4}}=0.5}\)

连分式(大型嵌套分式)

\cfrac{2}{c + \cfrac{2}{d + \cfrac{2}{4}}} = a

\({\displaystyle {\cfrac {2}{c+{\cfrac {2}{d+{\cfrac {2}{4}}}}}}=a}\)

大型不嵌套分式

\dfrac{2}{4} = 0.5 \qquad \dfrac{2}{c + \dfrac{2}{d + \dfrac{2}{4}}} = a

\({\displaystyle {\dfrac {2}{4}}=0.5\qquad {\dfrac {2}{c+{\dfrac {2}{d+{\dfrac {2}{4}}}}}}=a}\)

二项式系数

\dbinom{n}{r}=\binom{n}{n-r}=\mathrm{C}_n^r=\mathrm{C}_n^{n-r}

\({\displaystyle {\dbinom {n}{r}}={\binom {n}{n-r}}=\mathrm {C} _{n}^{r}=\mathrm {C} _{n}^{n-r}}\)

小型二项式系数

\tbinom{n}{r}=\tbinom{n}{n-r}=\mathrm{C}_n^r=\mathrm{C}_n^{n-r}

\({\displaystyle {\tbinom {n}{r}}={\tbinom {n}{n-r}}=\mathrm {C} _{n}^{r}=\mathrm {C} _{n}^{n-r}}\)

大型二项式系数

\binom{n}{r}=\dbinom{n}{n-r}=\mathrm{C}_n^r=\mathrm{C}_n^{n-r}

\({\displaystyle {\binom {n}{r}}={\dbinom {n}{n-r}}=\mathrm {C} _{n}^{r}=\mathrm {C} _{n}^{n-r}}\)

在以e为底的指数函数、极限和积分中尽量不要使用 \frac 符号:它会使整段函数看起来很怪,而且可能产生歧义。也正是因此它在专业数学排版中几乎从不出现。
横着写这些分式,中间使用斜线间隔 / (用斜线代替分数线)。

  • 例子:
\begin{array}{cc}
\mathrm{Bad} & \mathrm{Better} \\
\hline \\
e^{i\frac{\pi}2} \quad e^{\frac{i\pi}2}& e^{i\pi/2} \\
\int_{-\frac\pi2}^\frac\pi2 \sin x\,dx & \int_{-\pi/2}^{\pi/2}\sin x\,dx \\
\end{array}
  • 显示:
\[\begin{array}{cc}
\mathrm{Bad} & \mathrm{Better} \\
\hline \\
e^{i\frac{\pi}2} \quad e^{\frac{i\pi}2}& e^{i\pi/2} \\
\int_{-\frac\pi2}^\frac\pi2 \sin x\,dx & \int_{-\pi/2}^{\pi/2}\sin x\,dx \\
\end{array}
\]

矩阵、条件表达式、方程组

语法:

\begin{类型}
公式内容
\end{类型}

类型可以是:矩阵 matrix pmatrix bmatrix Bmatrix vmatrix Vmatrix、条件表达式 cases、多行对齐方程式 aligned、数组 array

在公式内容中:在每一行中插入 & 来指定需要对齐的内容,在每行结尾处使用 \\ 换行

无框矩阵

在开头使用 begin{matrix},在结尾使用 end{matrix},在中间插入矩阵元素,每个元素之间插入 & ,并在每行结尾处使用 \\

\begin{matrix}
x & y \\
z & v
\end{matrix}

\({\displaystyle {\begin{matrix}x&y\\z&v\end{matrix}}}\)

有框矩阵

在开头将 matrix 替换为 pmatrix bmatrix Bmatrix vmatrix Vmatrix

\begin{vmatrix}
x & y \\
z & v
\end{vmatrix}

\({\displaystyle {\begin{vmatrix}x&y\\z&v\end{vmatrix}}}\)

\begin{Vmatrix}
x & y \\
z & v
\end{Vmatrix}

\({\displaystyle {\begin{Vmatrix}x&y\\z&v\end{Vmatrix}}}\)

使用 \cdots \(\cdots\) , \ddots \(\ddots\) , \vdots \(\vdots\) 来输入省略符号

\begin{bmatrix}
0      & \cdots & 0      \\
\vdots & \ddots & \vdots \\
0      & \cdots & 0
\end{bmatrix}

\({\displaystyle {\begin{bmatrix}0&\cdots &0\\\vdots &\ddots &\vdots \\0&\cdots &0\end{bmatrix}}}\)

\begin{Bmatrix}
x & y \\
z & v
\end{Bmatrix}

\({\displaystyle {\begin{Bmatrix}x&y\\z&v\end{Bmatrix}}}\)

\begin{pmatrix}
x & y \\
z & v
\end{pmatrix}

\({\displaystyle {\begin{pmatrix}x&y\\z&v\end{pmatrix}}}\)

条件表达式

f(n) =
\begin{cases} 
n/2,  & \text{if }n\text{ is even} \\
3n+1, & \text{if }n\text{ is odd}
\end{cases}

\({\displaystyle f(n)={\begin{cases}n/2,&{\text{if }}n{\text{ is even}}\\3n+1,&{\text{if }}n{\text{ is odd}}\end{cases}}}\)

多行等式、同余式

人们经常想要一列整齐且居中的方程式序列。使用 \begin{aligned}…\end{aligned}

\begin{aligned}
f(x) & = (m+n)^2 \\
     & = m^2+2mn+n^2 \\
\end{aligned}

\({\displaystyle {\begin{aligned}f(x)&=(m+n)^{2}\\&=m^{2}+2mn+n^{2}\\\end{aligned}}}\)

begin{aligned}
3^{6n+3}+4^{6n+3} 
& \equiv (3^3)^{2n+1}+(4^3)^{2n+1}\\  
& \equiv 27^{2n+1}+64^{2n+1}\\  
& \equiv 27^{2n+1}+(-27)^{2n+1}\\ 
& \equiv 27^{2n+1}-27^{2n+1}\\
& \equiv 0 \pmod{91}\\
\end{aligned}

\({\displaystyle {\begin{aligned}3^{6n+3}+4^{6n+3}&\equiv (3^{3})^{2n+1}+(4^{3})^{2n+1}\\&\equiv 27^{2n+1}+64^{2n+1}\\&\equiv 27^{2n+1}+(-27)^{2n+1}\\&\equiv 27^{2n+1}-27^{2n+1}\\&\equiv 0{\pmod {91}}\\\end{aligned}}}\)

\begin{alignedat}{3}
f(x) & = (m-n)^2 \\
f(x) & = (-m+n)^2 \\
     & = m^2-2mn+n^2 \\
\end{alignedat}

\({\displaystyle {\begin{alignedat}{3}f(x)&=(m-n)^{2}\\f(x)&=(-m+n)^{2}\\&=m^{2}-2mn+n^{2}\\\end{alignedat}}}\)

方程组

\begin{cases}
3x + 5y +  z \\
7x - 2y + 4z \\
-6x + 3y + 2z
\end{cases}

\[{\displaystyle {\begin{cases}3x+5y+z\\7x-2y+4z\\-6x+3y+2z\end{cases}}}
\]

\left\{\begin{aligned}
3x + 5y +  z \\
7x - 2y + 4z \\
-6x + 3y + 2z
\end{aligned}\right.

\[\left\{\begin{aligned}
3x + 5y + z \\
7x – 2y + 4z \\
-6x + 3y + 2z
\end{aligned}\right.
\]

数组与表格

通常,一个格式化后的表格比单纯的文字或排版后的文字更具有可读性。数组和表格均以 \begin{array} 开头,并在其后定义列数及每一列的文本对齐属性,c l r 分别代表居中、左对齐及右对齐。若需要插入垂直分割线,在定义式中插入 | ,若要插入水平分割线,在下一行输入前插入 \hline 。与矩阵相似,每行元素间均须要插入 & ,每行元素以 \\ 结尾,最后以 \end{array} 结束数组。

  • 例子:
\begin{array}{c|lcr}
n & \text{左对齐} & \text{居中对齐} & \text{右对齐} \\
\hline
1 & 0.24 & 1 & 125 \\
2 & -1 & 189 & -8 \\
3 & -20 & 2000 & 1+10i
\end{array}
  • 显示:
\[\begin{array}{c|lcr}
n & \text{左对齐} & \text{居中对齐} & \text{右对齐} \\
\hline
1 & 0.24 & 1 & 125 \\
2 & -1 & 189 & -8 \\
3 & -20 & 2000 & 1+10i
\end{array}
\]

  • 例子:
\begin{array}{lcl}
z        & = & a \\
f(x,y,z) & = & x + y + z 
\end{array}
  • 显示:

\({\displaystyle {\begin{array}{lcl}z&=&a\\f(x,y,z)&=&x+y+z\end{array}}}\)

  • 例子:
\begin{array}{lcr}
z        & = & a \\
f(x,y,z) & = & x + y + z    
\end{array}
  • 显示:

\({\displaystyle {\begin{array}{lcr}z&=&a\\f(x,y,z)&=&x+y+z\end{array}}}\)

  • 例子:
\begin{array}{ccc}
a & b & S \\
\hline
0&0&1\\
0&1&1\\
1&0&1\\
1&1&0\\
\end{array}
  • 显示:
\[{\displaystyle {\begin{array}{ccc}a&b&S\\\hline 0&0&1\\0&1&1\\1&0&1\\1&1&0\\\end{array}}}
\]

嵌套数组或表格

多个数组/表格可 互相嵌套 并组成一组数组/一组表格。
使用嵌套前必须声明 $$ 符号。

  • 例子:
% outer vertical array of arrays 外层垂直表格
\begin{array}{c}
    % inner horizontal array of arrays 内层水平表格
    \begin{array}{cc}
        % inner array of minimum values 内层"最小值"数组
        \begin{array}{c|cccc}
        \text{min} & 0 & 1 & 2 & 3\\
        \hline
        0 & 0 & 0 & 0 & 0\\
        1 & 0 & 1 & 1 & 1\\
        2 & 0 & 1 & 2 & 2\\
        3 & 0 & 1 & 2 & 3
        \end{array}
    &
        % inner array of maximum values 内层"最大值"数组
        \begin{array}{c|cccc}
        \text{max}&0&1&2&3\\
        \hline
        0 & 0 & 1 & 2 & 3\\
        1 & 1 & 1 & 2 & 3\\
        2 & 2 & 2 & 2 & 3\\
        3 & 3 & 3 & 3 & 3
        \end{array}
    \end{array}
    % 内层第一行表格组结束
    \\
    % inner array of delta values 内层第二行Delta值数组
        \begin{array}{c|cccc}
        \Delta&0&1&2&3\\
        \hline
        0 & 0 & 1 & 2 & 3\\
        1 & 1 & 0 & 1 & 2\\
        2 & 2 & 1 & 0 & 1\\
        3 & 3 & 2 & 1 & 0
        \end{array}
        % 内层第二行表格组结束
\end{array}
  • 显示:
\[% outer vertical array of arrays 外层垂直表格
\begin{array}{c}
% inner horizontal array of arrays 内层水平表格
\begin{array}{cc}
% inner array of minimum values 内层”最小值”数组
\begin{array}{c|cccc}
\text{min} & 0 & 1 & 2 & 3\\
\hline
0 & 0 & 0 & 0 & 0\\
1 & 0 & 1 & 1 & 1\\
2 & 0 & 1 & 2 & 2\\
3 & 0 & 1 & 2 & 3
\end{array}
&
% inner array of maximum values 内层”最大值”数组
\begin{array}{c|cccc}
\text{max}&0&1&2&3\\
\hline
0 & 0 & 1 & 2 & 3\\
1 & 1 & 1 & 2 & 3\\
2 & 2 & 2 & 2 & 3\\
3 & 3 & 3 & 3 & 3
\end{array}
\end{array}
% 内层第一行表格组结束
\\
% inner array of delta values 内层第二行Delta值数组
\begin{array}{c|cccc}
\Delta&0&1&2&3\\
\hline
0 & 0 & 1 & 2 & 3\\
1 & 1 & 0 & 1 & 2\\
2 & 2 & 1 & 0 & 1\\
3 & 3 & 2 & 1 & 0
\end{array}
% 内层第二行表格组结束
\end{array}
\]

用数组实现带分割符号的矩阵

  • 例子:
$$
\left[
    \begin{array}{cc|c}
      1&2&3\\
      4&5&6
    \end{array}
\right]
$$
  • 显示:
\[\left[
\begin{array}{cc|c}
1&2&3\\
4&5&6
\end{array}
\right]
\]

其中 cc|c 代表在一个三列矩阵中的第二和第三列之间插入分割线。

字体

希腊字母

输入 \小写希腊字母英文全称\首字母大写希腊字母英文全称 来分别输入小写和大写希腊字母。

\Alpha \Beta \Gamma \Delta \Epsilon \Zeta \Eta \Theta

\({\displaystyle \mathrm {A} \mathrm {B} \Gamma \Delta \mathrm {E} \mathrm {Z} \mathrm {H} \Theta }\)

\Iota \Kappa \Lambda \Mu \Nu \Xi \Omicron \Pi

\({\displaystyle \mathrm {I} \mathrm {K} \Lambda \mathrm {M} \mathrm {N} \mathrm {O} \Xi \Pi }\)

\Rho \Sigma \Tau \Upsilon \Phi \Chi \Psi \Omega

\({\displaystyle \mathrm {P} \Sigma \mathrm {T} \Upsilon \Phi \mathrm {X} \Psi \Omega }\)

\alpha \beta \gamma \delta \epsilon \zeta \eta \theta

\({\displaystyle \alpha \beta \gamma \delta \epsilon \zeta \eta \theta}\)

\iota \kappa \lambda \mu \nu \omicron \xi \pi

\({\displaystyle \iota \kappa \lambda \mu \nu \mathrm {o} \xi \pi }\)

\rho \sigma \tau \upsilon \phi \chi \psi \omega

\({\displaystyle \rho \sigma \tau \upsilon \phi \chi \psi \omega}\)

部分字母有变量专用形式,以 \var- 开头。

\varepsilon \digamma \varkappa \varpi

\({\displaystyle \varepsilon \digamma \varkappa \varpi}\)

\varrho \varsigma \vartheta \varphi

\({\displaystyle \varrho \varsigma \vartheta \varphi}\)

希伯来符号

\aleph \beth \gimel \daleth

\({\displaystyle \aleph \beth \gimel \daleth}\)

部分字体的简称

若要对公式的某一部分字符进行字体转换,可以用 {\字体 {需转换的部分字符}} 命令,其中 \字体 部分可以参照下表选择合适的字体。一般情况下,公式默认为意大利体 \(italic\)

|输入|说明|显示|输入|说明|显示|
|:–

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