5楼: Originally posted by guanmm at 2016-09-12 16:13:45
不懂，学习了

syms a b c d
syms A S D

A = [a, b; c, d]
A =
[ a, b]
[ c, d]

[V,D] = eig(A)
V =
[ -(-1/2*a+1/2*d-1/2*(a^2-2*a*d+d^2+4*b*c)^(1/2))/c, -(- 1/2*a+1/2*d+1/2*(a^2-2*a*d+d^2+4*b*c)^(1/2))/c]
[ 1, 1]
D =
[ 1/2*a+1/2*d+1/2*(a^2-2*a*d+d^2+4*b*c)^(1/2), 0]
[ 0, 1/2*a+1/2*d-1/2*(a^2-2*a*d+d^2+4*b*c)^(1/2)]

Snum = [-1,1;1,0]'
Snum =
-1 1
1 0

Dnum = [2, 0; 0, 3]
Dnum =
2 0
0 3

Anum = Snum * Dnum * inv(Snum)
Anum =
3 1
0 2

[Vnum,Dnum] = eig(Anum)
Vnum =
1 -0.70711
0 0.70711
Dnum =
3 0
0 2