LaTeX 数学模式常用注记

强力软件

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Matrix

\begin{bmatrix}
    a & \cdots & b \\
    \vdots & \ddots & \vdots \\
    c & \cdots & d
\end{bmatrix}

$$\begin{bmatrix} a & \cdots & b \\ \vdots & \ddots & \vdots \\ c & \cdots & d \end{bmatrix}$$

Besides pmatrix, Bmatrix, and vmatrix works as well. Use smallmatrix for inline matrix.

Aligned

\begin{align}
a + b & = c \\
    & = \sin(x)
\end{align}

$$\begin{align} a + b & = c \\ & = \sin(x) \end{align}$$

Cases

f(n) = \begin{cases}
    \frac n 2 & \text{$n$ is even} \\
    \frac {n - 1} 2 & \text{otherwise}
\end{cases}

$$f(n) = \begin{cases} \frac n 2 & \text{$n$ is even} \\ \frac {n - 1} 2 & \text{otherwise} \end{cases}$$

Arrays

$$
\begin{array}{l|rc}
    n & \text{name} & \text{age} \\
    1 & \text{John} & 18 \\
    1 & \text{A} & 17
\end{array}
$$

$$\begin{array}{l|rc} n & \text{name} & \text{age} \\ 1 & \text{John} & 18 \\ 1 & \text{A} & 17 \end{array}$$

Sum of equations

\left\{ \begin{array}{rcl}
    x + y & = & 10 \\
    y & = & 0
\end{array} \right.

$$\left\{ \begin{array}{rcl} x + y & = & 10 \\ y & = & 0 \end{array} \right.$$

Iff

\begin{array}{cl}
    & A(x) + 1 = e^{-1} \\
    \iff & f_x = 0 \\
    \iff & g_x \ne 0
\end{array}

$$\begin{array}{cl} & A(x) + 1 = e^{-1} \\ \iff & f_x = 0 \\ \iff & g_x \ne 0 \end{array}$$

New command

\newcommand{\aboutthesame}[2]{\mathcal #1 \cong \mathcal #2}
\aboutthesame A B

$$\newcommand{\aboutthesame}[2]{\mathcal #1 \cong \mathcal #2} \aboutthesame A B$$

I Love It, :).