1 -2 6 -3
-2 3 -2 1
0 0 -7 5
0 0 3 -2
--分块方法:2,2行,2,2列
=
B C
0 D
其逆矩阵 =
B^-1 -B^-1CD^-1
0 D^-1
B^-1 =
-3 -2
-2 -1
D^-1=
2 5
3 7
B^-1*C*D^-1=
-7 -21
-5 -15
代入得 A^-1=
-3 -2 7 21
-2 -1 5 15
0 0 2 5
0 0 3 7