1.Am×nA_{m\times n}Am×n的矩阵A=[a11a12⋯a1na21a22⋯a2n⋮⋮⋱⋮am1am2⋯amn] A=\left[\begin{array}{cccc}{a_{11}} & {a_{12}} & {\cdots} & {a_{1 n}} \\ {a_{21}} & {a_{22}} & {\cdots} & {a_{2 n}} \\ {\vdots} & {\vdots} & {\ddots} & {\vdots} \\ {a_{m 1}} & {a_{m 2}} & {\cdots} & {a_{m n}}\end{array}\right] A=⎣⎢⎢⎢⎡a11a21⋮am1a12a22⋮am2⋯⋯⋱⋯a1na2n⋮amn⎦⎥⎥⎥⎤
$$
A=\left[\begin{array}{cccc}{a_{11}} & {a_{12}} & {\cdots} & {a_{1 n}} \\ {a_{21}} & {a_{22}} & {\cdots} & {a_{2 n}} \\ {\vdots} & {\vdots} & {\ddots} & {\vdots} \\ {a_{m 1}} & {a_{m 2}} & {\cdots} & {a_{m n}}\end{array}\right]
$$
2.矩阵与向量相乘A⋅x⃗=(a11x1+a12x2+⋯+a1nxna21x1+a22x2+⋯+a2nxn⋮am1x1+am2x2+⋯+amnxn) A \cdot \vec{x}=\left(\begin{array}{c}{a_{11} x_{1}+a_{12} x_{2}+\cdots+a_{1 n} x_{n}} \\ {a_{21} x_{1}+a_{22} x_{2}+\cdots+a_{2 n} x_{n}} \\ {\vdots} \\ {a_{m 1} x_{1}+a_{m 2} x_{2}+\cdots+a_{m n} x_{n}}\end{array}\right) A⋅x=⎝⎜⎜⎜⎛a11x1+a12x2+⋯+a1nxna21x1+a22x2+⋯+a2nxn⋮am1x1+am2x2+⋯+amnxn⎠⎟⎟⎟⎞
$$
A \cdot \vec{x}=\left(\begin{array}{c}{a_{11} x_{1}+a_{12} x_{2}+\cdots+a_{1 n} x_{n}} \\ {a_{21} x_{1}+a_{22} x_{2}+\cdots+a_{2 n} x_{n}} \\ {\vdots} \\ {a_{m 1} x_{1}+a_{m 2} x_{2}+\cdots+a_{m n} x_{n}}\end{array}\right)
$$
3.特征表示Ax=λx A x=\lambda x Ax=λx
$$
A x=\lambda x
$$
4.矩阵相似A=P−1BP A=P^{-1} B P A=P−1BP
$$
A=P^{-1} B P
$$