填空题 (共 4 题 ),请把答案直接填写在答题纸上
设 $A =\left(\begin{array}{ccc}1 & -1 & 1 \\ 1 & 1 & -1\end{array}\right), B =\left(\begin{array}{ccc}1 & 2 & 3 \\ -1 & -2 & 4\end{array}\right)$ .则 $A +2 B =$
若矩阵 $A =\left(\begin{array}{ccc}1 & -4 & 2 \\ -1 & 4 & -2\end{array}\right), B =\left(\begin{array}{cc}1 & 2 \\ -1 & 3 \\ 5 & -2\end{array}\right)$ ,则 $A B$ 的第 2 行第 1 列的元素为
已知 $A ^2=\left(\begin{array}{lll}2 & 1 & 0 \\ 1 & 1 & 0 \\ 0 & 0 & 4\end{array}\right), A ^5=\left(\begin{array}{ccc}8 & 5 & 0 \\ 5 & 3 & 0 \\ 0 & 0 & -32\end{array}\right)$ ,那么矩阵 $A =$ $\qquad$ .
分块矩阵 $\left(\begin{array}{ll}\boldsymbol{A} & \boldsymbol{E} \\ \boldsymbol{E} & \boldsymbol{O}\end{array}\right)$ 的逆矩阵为
解答题 (共 18 题 ),解答过程应写出必要的文字说明、证明过程或演算步骤
$$
\left(\begin{array}{rrrr}
2 & 1 & 4 & 0 \\
1 & -1 & 3 & 4
\end{array}\right)\left(\begin{array}{rrr}
1 & 3 & 1 \\
0 & -1 & 2 \\
1 & -3 & 1 \\
4 & 0 & -2
\end{array}\right)
$$
$$
\left(x_1, x_2, x_3\right)\left(\begin{array}{lll}
a_{11} & a_{12} & a_{13} \\
a_{12} & a_{22} & a_{23} \\
a_{13} & a_{23} & a_{33}
\end{array}\right)\left(\begin{array}{l}
x_1 \\
x_2 \\
x_3
\end{array}\right)
$$
已知两个线性变换
$$
\left\{\begin{array} { l }
{ x _ { 1 } = 2 y _ { 1 } + y _ { 3 } , } \\
{ x _ { 2 } = - 2 y _ { 1 } + 3 y _ { 2 } + 2 y _ { 3 } } \\
{ x _ { 3 } = 4 y _ { 1 } + y _ { 2 } + 5 y _ { 3 } , }
\end{array} \left\{\begin{array}{l}
y_1=-3 z_1+z_2, \\
y_2=2 z_1+z_3, \\
y_3=-3 z_3,
\end{array}\right.\right.
$$
求从 $z_1, z_2, z_3$ 到 $x_1, x_2, x_3$ 的线性变换.
(1) 设 $\boldsymbol{A}, \boldsymbol{B}$ 为 $n$ 阶矩阵, 且 $\boldsymbol{A}$ 为对称阵, 证明 $\boldsymbol{B}^{\mathrm{T}} \boldsymbol{A} \boldsymbol{B}$ 也是对称阵;
(2) 设 $\boldsymbol{A}, \boldsymbol{B}$ 都是 $n$ 阶对称阵,证明 $\boldsymbol{A B}$ 是对称阵的充要条件是 $\boldsymbol{A B}=\boldsymbol{B} \boldsymbol{A}$.
设 $\boldsymbol{A}=\left(\begin{array}{rrr}0 & 3 & 3 \\ 1 & 1 & 0 \\ -1 & 2 & 3\end{array}\right), A B=A+2 B$, 求 $\boldsymbol{B}$.
设 $\boldsymbol{A}=\left(\begin{array}{lll}1 & 0 & 1 \\ 0 & 2 & 0 \\ 1 & 0 & 1\end{array}\right)$, 且 $\boldsymbol{A} \boldsymbol{B}+\boldsymbol{E}=\boldsymbol{A}^2+\boldsymbol{B}$, 求 $\boldsymbol{B}$.
设 $\boldsymbol{A}=\operatorname{diag}(1,-2,1), \boldsymbol{A}^* \boldsymbol{B} \boldsymbol{A}=2 \boldsymbol{B} \boldsymbol{A}-8 \boldsymbol{E}$, 求 $\boldsymbol{B}$.
设 $\boldsymbol{P}^{-1} \boldsymbol{A} \boldsymbol{P}=\boldsymbol{\Lambda}$, 其中 $\boldsymbol{P}=\left(\begin{array}{rr}-1 & -4 \\ 1 & 1\end{array}\right), \boldsymbol{\Lambda}=\left(\begin{array}{rr}-1 & 0 \\ 0 & 2\end{array}\right)$, 求 $\boldsymbol{A}^{11}$.
计算 $\left(\begin{array}{llll}1 & 2 & 1 & 0 \\ 0 & 1 & 0 & 1 \\ 0 & 0 & 2 & 1 \\ 0 & 0 & 0 & 3\end{array}\right)\left(\begin{array}{rrrr}1 & 0 & 3 & 1 \\ 0 & 1 & 2 & -1 \\ 0 & 0 & -2 & 3 \\ 0 & 0 & 0 & -3\end{array}\right)$ 。
设 $A , B$ 均为 3 阶矩阵, $E$ 为 3 阶单位矩阵, 已知 $A B =2 A + B , B =\left[\begin{array}{lll}2 & 0 & 2 \\ 0 & 4 & 0 \\ 2 & 0 & 2\end{array}\right]$, 求 $A - E$.
设 $A =\left(\begin{array}{ccc}1 & 2 & 0 \\ 3 & 4 & 0 \\ -1 & 2 & 1\end{array}\right), B =\left(\begin{array}{ccc}2 & 3 & -1 \\ -2 & 4 & 0\end{array}\right)$ .求(1) $A B ^{ T }$ ;(2)$|4 A |$ .
$ A, B \in M_n$ ,证明 $\left|\begin{array}{cc}A & i \\ I & B\end{array}\right|=|A B-I|$ .
已知 $A, B, C, D \in M_n$ .且 $A$ 可逆,$A C=C A$ ,设 $M=$ $\left(\begin{array}{ll}A & B \\ C & D\end{array}\right)$ ,求证:
$$
|M|=|A D-C B| .
$$
计算 $$
\left|\begin{array}{cccc}
1+x_1 y_1 & x_1 y_2 & \cdots & x_1 y_n \\
x_2 y_1 & 1+x_2 y_2 & \cdots & x_2 y_n \\
\vdots & \vdots & & \vdots \\
x_n y_1 & x_n y_2 & \cdots & 1+x_n y_n
\end{array}\right|
$$
已知矩阵 $A=\left(\begin{array}{lll}2 & 0 & 1 \\ 1 & 0 & 5 \\ 3 & 2 & 5\end{array}\right), B=\left(\begin{array}{ccc}1 & 1 & 2 \\ 1 & -1 & 2 \\ 3 & 2 & 4\end{array}\right)$ 满足 $A X B=B X B+I$ ,其中 $I$ 是 3 阶单位矩阵,求 $X$ 。
解矩阵方程 $\left(\begin{array}{ll}-1 & 4 \\ -2 & 7\end{array}\right) X =\left(\begin{array}{ccc}2 & -1 & 3 \\ 1 & 0 & -2\end{array}\right)$
设 $\boldsymbol{\alpha}_1, \boldsymbol{\alpha}_2, \boldsymbol{\alpha}, \boldsymbol{\beta}$ 为 3 维列向量,矩阵 $\boldsymbol{A}=\left(\boldsymbol{\alpha}_1, \boldsymbol{\alpha}_2, \boldsymbol{\alpha}\right), \boldsymbol{B}=\left(2 \boldsymbol{\alpha}_1, \boldsymbol{\alpha}_2, \boldsymbol{\beta}\right)$ ,且已知行列式 $\operatorname{det} \boldsymbol{A}=1, \operatorname{det} \boldsymbol{B}=-2$ ,计算 $\operatorname{det}(2 \boldsymbol{A}+\boldsymbol{B})$ .
解矩阵方程 $\mathrm{AX}=\mathrm{B}$ ,其中
$$
A=\left(\begin{array}{lll}
1 & 2 & 3 \\
2 & 2 & 1 \\
3 & 4 & 3
\end{array}\right), \quad B=\left(\begin{array}{ll}
2 & 5 \\
3 & 1 \\
4 & 3
\end{array}\right)
$$