测试
行间插入
\\(a + b\\)\(a + b\)
另取一行
$$a + b$$$$a + b$$
下标
$$x_1$$
$$x_1^2$$
$$x^2_1$$
$$x_{22}^{(n)}$$
$${}^*x^*$$
$$x_{balabala}^{bala}$$$$x_1$$
$$x_1^2$$
$$x^2_1$$
$$x_{22}^{(n)}$$
$${}^x^$$
$$x_{balabala}^{bala}$$
分式
$$\frac{x+y}{2}$$
$$\frac{1}{1+\frac{1}{2}}$$$$\frac{x+y}{2}$$
$$\frac{1}{1+\frac{1}{2}}$$
根式
$$\sqrt{2}<\sqrt[3]{3}$$
$$\sqrt{1+\sqrt[p]{1+a^2}}$$
$$\sqrt{1+\sqrt[^p\!]{1+a^2}}$$$$\sqrt{2}<\sqrt[3]{3}$$
$$\sqrt{1+\sqrt[p]{1+a^2}}$$
$$\sqrt{1+\sqrt[^p!]{1+a^2}}$$
求和积分
$$\sum_{k=1}^{n}\frac{1}{k}$$
$\sum_{k=1}^n\frac{1}{k}$
$$\int_a^b f(x)dx$$
$\int_a^b f(x)dx$$$\sum_{k=1}^{n}\frac{1}{k}$$
$\sum_{k=1}^n\frac{1}{k}$
$$\int_a^b f(x)dx$$
$\int_a^b f(x)dx$
空格
紧贴 $a\!b$
没有空格 $ab$
小空格 a\,b
中等空格 a\;b
大空格 a\ b
quad空格 $a\quad b$
两个quad空格 $a\qquad b$紧贴 $a!b$
没有空格 $ab$
小空格 a,b
中等空格 a;b
大空格 a\ b
quad空格 $a\quad b$
两个quad空格 $a\qquad b$
$$\int_a^b f(x)\mathrm{d}x$$
$$\int_a^b f(x)\,\mathrm{d}x$$$$\int_a^b f(x)\mathrm{d}x$$
$$\int_a^b f(x),\mathrm{d}x$$
公式界定符
\( ( \)
\( ) \)
\( [ \)
\( ] \)
\( \{ \)
\( \} \)
\( | \)
\( \| \)
掘金：
$ ( $
$ ) $
$ [ $
$ ] $
$ { $
$ } $
$ | $
$ | $
矩阵
$$\begin{matrix}1 & 2\\\\3 &4\end{matrix}$$
$$\begin{pmatrix}1 & 2\\\\3 &4\end{pmatrix}$$
$$\begin{bmatrix}1 & 2\\\\3 &4\end{bmatrix}$$
$$\begin{Bmatrix}1 & 2\\\\3 &4\end{Bmatrix}$$
$$\begin{vmatrix}1 & 2\\\\3 &4\end{vmatrix}$$
$$\left|\begin{matrix}1 & 2\\\\3 &4\end{matrix}\right|$$
$$\begin{Vmatrix}1 & 2\\\\3 &4\end{Vmatrix}$$$$\begin{matrix}1 & 2\\3 &4\end{matrix}$$
$$\begin{pmatrix}1 & 2\\3 &4\end{pmatrix}$$
$$\begin{bmatrix}1 & 2\\3 &4\end{bmatrix}$$
$$\begin{Bmatrix}1 & 2\\3 &4\end{Bmatrix}$$
$$\begin{vmatrix}1 & 2\\3 &4\end{vmatrix}$$
$$\left|\begin{matrix}1 & 2\\3 &4\end{matrix}\right|$$
$$\begin{Vmatrix}1 & 2\\3 &4\end{Vmatrix}$$
排版数组
\mathbf{X} =
\left( \begin{array}{ccc}
x\_{11} & x\_{12} & \ldots \\\\
x\_{21} & x\_{22} & \ldots \\\\
\vdots & \vdots & \ddots
\end{array} \right)\mathbf{X} =
\left( \begin{array}{ccc}
x_{11} & x_{12} & \ldots \\
x_{21} & x_{22} & \ldots \\
\vdots & \vdots & \ddots
\end{array} \right)
长公式
$$
\begin{multline}
x = a+b+c+{} \\\\
d+e+f+g
\end{multline}
$$
$$
\begin{aligned}
x ={}& a+b+c+{} \\\\
&d+e+f+g
\end{aligned}
$$$$
\begin{multline}
x = a+b+c+{} \\
d+e+f+g
\end{multline}
$$
$$
\begin{aligned}
x ={}& a+b+c+{} \\
&d+e+f+g
\end{aligned}
$$
公式组
$$
\begin{gather}
a = b+c+d \\\\
x = y+z
\end{gather}
$$
$$
\begin{align}
a &= b+c+d \\\\
x &= y+z
\end{align}
$$$$
\begin{gather}
a = b+c+d \\
x = y+z
\end{gather}
$$
$$
\begin{align}
a &= b+c+d \\
x &= y+z
\end{align}
$$
分段函数
$$
y=\begin{cases}
-x,\quad x\leq 0 \\\\
x,\quad x>0
\end{cases}
$$$$
y=\begin{cases}
-x,\quad x\leq 0 \\
x,\quad x>0
\end{cases}
$$
划线数组
$$
\left(\begin{array}{|c|c|}
1 & 2 \\\\
\\hline
3 & 4
\end{array}\right)
$$$$
\left(\begin{array}{|c|c|}
1 & 2 \\
\hline
3 & 4
\end{array}\right)
$$
制表
$$
\begin{array}{|c|c|}
\hline
{1111111111} & 2 \\\\
\hline
3 & 4 \\\\
\hline
\end{array}
$$$$
\begin{array}{|c|c|}
\hline
{1111111111} & 2 \\
\hline
3 & 4 \\
\hline
\end{array}
$$
常用希腊字母
$$
\begin{array}{|c|c|c|c|c|c|c|c|}
\hline
{\alpha} & {\backslash alpha} & {\theta} & {\backslash theta} & {o} & {o} & {\upsilon} & {\backslash upsilon} \\\\
\hline
{\beta} & {\backslash beta} & {\vartheta} & {\backslash vartheta} & {\pi} & {\backslash pi} & {\phi} & {\backslash phi} \\\\
\hline
{\gamma} & {\backslash gamma} & {\iota} & {\backslash iota} & {\varpi} & {\backslash varpi} & {\varphi} & {\backslash varphi} \\\\
\hline
{\delta} & {\backslash delta} & {\kappa} & {\backslash kappa} & {\rho} & {\backslash rho} & {\chi} & {\backslash chi} \\\\
\hline
{\epsilon} & {\backslash epsilon} & {\lambda} & {\backslash lambda} & {\varrho} & {\backslash varrho} & {\psi} & {\backslash psi} \\\\
\hline
{\varepsilon} & {\backslash varepsilon} & {\mu} & {\backslash mu} & {\sigma} & {\backslash sigma} & {\omega} & {\backslash omega} \\\\
\hline
{\zeta} & {\backslash zeta} & {\nu} & {\backslash nu} & {\varsigma} & {\backslash varsigma} & {} & {} \\\\
\hline
{\eta} & {\backslash eta} & {\xi} & {\backslash xi} & {\tau} & {\backslash tau} & {} & {} \\\\
\hline
{\Gamma} & {\backslash Gamma} & {\Lambda} & {\backslash Lambda} & {\Sigma} & {\backslash Sigma} & {\Psi} & {\backslash Psi} \\\\
\hline
{\Delta} & {\backslash Delta} & {\Xi} & {\backslash Xi} & {\Upsilon} & {\backslash Upsilon} & {\Omega} & {\backslash Omega} \\\\
\hline
{\Omega} & {\backslash Omega} & {\Pi} & {\backslash Pi} & {\Phi} & {\backslash Phi} & {} & {} \\\\
\hline
\end{array}
$$$$
\begin{array}{|c|c|c|c|c|c|c|c|}
\hline
{\alpha} & {\backslash alpha} & {\theta} & {\backslash theta} & {o} & {o} & {\upsilon} & {\backslash upsilon} \\
\hline
{\beta} & {\backslash beta} & {\vartheta} & {\backslash vartheta} & {\pi} & {\backslash pi} & {\phi} & {\backslash phi} \\
\hline
{\gamma} & {\backslash gamma} & {\iota} & {\backslash iota} & {\varpi} & {\backslash varpi} & {\varphi} & {\backslash varphi} \\
\hline
{\delta} & {\backslash delta} & {\kappa} & {\backslash kappa} & {\rho} & {\backslash rho} & {\chi} & {\backslash chi} \\
\hline
{\epsilon} & {\backslash epsilon} & {\lambda} & {\backslash lambda} & {\varrho} & {\backslash varrho} & {\psi} & {\backslash psi} \\
\hline
{\varepsilon} & {\backslash varepsilon} & {\mu} & {\backslash mu} & {\sigma} & {\backslash sigma} & {\omega} & {\backslash omega} \\
\hline
{\zeta} & {\backslash zeta} & {\nu} & {\backslash nu} & {\varsigma} & {\backslash varsigma} & {} & {} \\
\hline
{\eta} & {\backslash eta} & {\xi} & {\backslash xi} & {\tau} & {\backslash tau} & {} & {} \\
\hline
{\Gamma} & {\backslash Gamma} & {\Lambda} & {\backslash Lambda} & {\Sigma} & {\backslash Sigma} & {\Psi} & {\backslash Psi} \\
\hline
{\Delta} & {\backslash Delta} & {\Xi} & {\backslash Xi} & {\Upsilon} & {\backslash Upsilon} & {\Omega} & {\backslash Omega} \\
\hline
{\Omega} & {\backslash Omega} & {\Pi} & {\backslash Pi} & {\Phi} & {\backslash Phi} & {} & {} \\
\hline
\end{array}
$$
来自
https://juejin.im/post/5a6721bd518825733201c4a2