$LaTex$
将数学公式写在$ $之间，代表的是插入行内数学公式。
将数学公式写在$$ $$之间，会使公式独立成一行并强制居中。
$\left\vert a\right\vert$
$\left\vert a\right\vert$
$\lVert z\rVert$
$\lVert z\rVert$
$\infty$
$\infty$
$a\equiv b\pmod c$
$a\equiv b\pmod c$
$a\bmod b$
$a\bmod b$
$\mid \nmid \shortmid \nshortmid$
$\mid \nmid \shortmid \nshortmid$
$\sqrt{2} \sqrt{n}{x}$
$\sqrt{2} \sqrt[n]{x}$
$\pm \mp \dotplus$
$\pm \mp \dotplus$
$\times \div \divideontimes$
$\times \div \divideontimes$
$\in \not\in \ni \not\ni$
$\in \not\in \ni \not\ni$
$\cap \Cap \sqcap \bigcap$
$\cap \Cap \sqcap \bigcap$
$\cup \Cup \sqcup \bigcup \bigsqcup \uplus \biguplus$
$\cup \Cup \sqcup \bigcup \bigsqcup \uplus \biguplus$
$\subset \Subset \sqsubset$
$\subset \Subset \sqsubset$
$\supset \Supset \sqsupset$
$\supset \Supset \sqsupset$
$\subseteq \nsubseteq \subsetneq \varsubsetneq \sqsubseteq$
$\subseteq \nsubseteq \subsetneq \varsubsetneq \sqsubseteq$
$\supseteq \nsupseteq \supsetneq \varsupsetneq \sqsupseteq$
$\supseteq \nsupseteq \supsetneq \varsupsetneq \sqsupseteq$
$\subseteqq \nsubseteqq \subsetneqq \varsubsetneqq$
$\subseteqq \nsubseteqq \subsetneqq \varsubsetneqq$
$\supseteqq \nsupseteqq \supsetneqq \varsupsetneqq$
$\supseteqq \nsupseteqq \supsetneqq \varsupsetneqq$
$\ne \neq \equiv \not\equiv$
$\ne \neq \equiv \not\equiv$
$\sim \nsim \backsim \thicksim \simeq \backsimeq \eqsim \cong \ncong$
$\sim \nsim \backsim \thicksim \simeq \backsimeq \eqsim \cong \ncong$
$\approx \thickapprox \approxeq \asymp \propto \varpropto$
$\approx \thickapprox \approxeq \asymp \propto \varpropto$
$\leqslant \geqslant$
$\leqslant \geqslant$
$\forall \therefore \because \And$
$\forall \therefore \because \And$
$\overline{abc} \underline{abc}$
$\overline{abc} \underline{abc}$
$a^2$
$a^2$
$a_2$
$a_2$
${}^2_1\!X^3_4$
${}^2_1\!X^3_4$
$\vec{x} \overleftarrow{AB} \overrightarrow{AB} \widehat{AB}$
$\vec{x} \overleftarrow{AB} \overrightarrow{AB} \widehat{AB}$
$\overset{\frown}{AB}$
$\overset{\frown}{AB}$
$\overbrace{1+2+\cdots+100}$
$\overbrace{1+2+\cdots+100}$
$\begin{matrix}5050\\\overbrace{1+2+\cdots+100}\end{matrix}$
$\begin{matrix}5050\\\overbrace{1+2+\cdots+100}\end{matrix}$
$\underbrace{1+2+\cdots+100}$
$\underbrace{1+2+\cdots+100}$
$\begin{matrix}\underbrace{1+2+\cdots+100}\\5050\end{matrix}$
$\begin{matrix}\underbrace{1+2+\cdots+100}\\5050\end{matrix}$
$\sum_{i=1}^na_i \sum\limits_{i=1}^na_i$
$\sum_{i=1}^na_i \sum\limits_{i=1}^na_i$
$\prod_{i=1}^na_i \prod\limits_{i=1}^na_i$
$\prod_{i=1}^na_i \prod\limits_{i=1}^na_i$
$\lim_{n\to\infty}a_i \lim\limits_{n\to\infty}a_i$
$\lim_{n\to\infty}a_i \lim\limits_{n\to\infty}a_i$
$\int_{-x}^{x}a^x\,dx$
$\int_{-N}^{N}a^x\,dx$
$\frac{1}{2}$
$\frac{1}{2}$
$\dbinom{n}{m}$
$\dbinom{n}{m}$
$\begin{vmatrix}a&b\\c&d\end{vmatrix}$
$\begin{vmatrix}a&b\\c&d\end{vmatrix}$
$\begin{bmatrix}a&\cdots&b\\\vdots&\ddots&\vdots\\c&\cdots&d\end{bmatrix}$
$\begin{bmatrix}a&\cdots&b\\\vdots&\ddots&\vdots\\c&\cdots&d\end{bmatrix}$
$\begin{Bmatrix}a&c\\b&d\end{Bmatrix}$
$\begin{Bmatrix}a&c\\b&d\end{Bmatrix}$
$\begin{pmatrix}a&c\\b&d\end{pmatrix}$
$\begin{pmatrix}a&c\\b&d\end{pmatrix}$
$f(x)=\begin{cases}x-1&x\leqslant3\\x^2+3x-1&x>3\end{cases}$
\begin{cases}x-1&x\leqslant3\\x^2+3x-1&x>3\end{cases}
$\begin{cases}2x+9y-5z=10\\4x+20y+z=24\\x-\frac{1}{2}y+3z=8\end{cases}$
\begin{cases}2x+9y-5z=10\\4x+20y+z=24\\x-\frac{1}{2}y+3z=8\end{cases}
$\begin{aligned}f(x)&=(x+1)^2\\&=x^2+2x+1\end{aligned}$
$\begin{aligned}f(x)&=(x+1)^2\\&=x^2+2x+1\end{aligned}$
$\begin{aligned}a_1&=1\\a_2&=2\\&\dots\\a_n&=n\end{aligned}$
$\begin{aligned}a_1&=1\\a_2&=2\\&\dots\\a_n&=n\end{aligned}$
$\begin{array}{|c|c||c|}x&y&z\\8&2&4\\2&3&9\\10&\frac{3}{4}&\sqrt{3}\\a&b&c\end{array}$
$\begin{array}{|c|c||c|}x&y&z\\8&2&4\\2&3&9\\10&\frac{3}{4}&\sqrt{3}\\a&b&c\end{array}$
$\alpha\beta\gamma\delta\epsilon\zeta\eta\theta$
$\alpha\beta\gamma\delta\epsilon\zeta\eta\theta$
$\boxed{\sum\limits_{i=1}^{n}i=\frac{n(n-1)}{2}}$
$\boxed{\sum\limits_{i=1}^{n}i=\frac{n(n-1)}{2}}$
来源：https://www.cnblogs.com/gzezzry/p/12203041.html