连乘 ∏ i = 1 n \prod\limits_{i=1}^n i=1∏n
\prod\limits_{i=1}^n向上取整 ⌈ x ⌉ \lceil x \rceil ⌈x⌉
$\lceil x \rceil$
向下取整 ⌊ x ⌋ \lfloor x \rfloor ⌊x⌋
$\lfloor x \rfloor$
均值 x ˉ \bar x xˉ
$\bar x$
大括号
f ( x ) = { 0 x=0 1 x!=0 f(x)= \begin{cases} 0& \text{x=0}\\ 1& \text{x!=0} \end{cases} f(x)={01x=0x!=0
$$
f(x)=
\begin{cases}
0& \text{x=0}\\
1& \text{x!=0}\\
\end{cases}
$$
矩阵
S = [ x 11 x 12 ⋯ x 1 m x 21 x 22 ⋯ x 2 m ⋮ ⋮ ⋱ ⋮ x n 1 x n 2 ⋯ x n m ] S= \begin{bmatrix} x_{11} & x_{12} & \cdots & x_{1m} \\ x_{21} & x_{22} & \cdots & x_{2m} \\ \vdots & \vdots & \ddots & \vdots \\ x_{n1} & x_{n2} & \cdots\ & x_{nm} \\ \end{bmatrix} S=⎣⎢⎢⎢⎡x11x21⋮xn1x12x22⋮xn2⋯⋯⋱⋯ x1mx2m⋮xnm⎦⎥⎥⎥⎤
$$
S=
\begin{bmatrix}
x_{11} & x_{12} & \cdots & x_{1m} \\
x_{21} & x_{22} & \cdots & x_{2m} \\
\vdots & \vdots & \ddots & \vdots \\
x_{n1} & x_{n2} & \cdots\ & x_{nm} \\
\end{bmatrix}
$$
使 L a t e x \rm Latex Latex字符斜体变成正体
\rm
小圆点 ∙ \bullet ∙
\bullet
