[求助] 怎样将正交变换化为标准型如下题　　谢谢

A =

1 2 0 -2
2 1 2 0
0 2 1 -2
-2 0 -2 1

?[x,lamda]=eig(A)

x =

0.5774 0.4082 0.5000 -0.5000
0.4082 -0.5774 0.5000 0.5000
-0.5774 -0.4082 0.5000 -0.5000
0.4082 -0.5774 -0.5000 -0.5000
x为换基矩阵，将系数矩阵转换为对角阵