正确答案
>> syms a11 a12 a21 a22;
>> A=[a11,a12;a21,a22]
>> AD=det(A) % 行列式
>> AI=inv(A) % 逆
>> AE=eig(A) % 特征值
A =
[ a11, a12]
[ a21, a22]
AD =
a11*a22-a12*a21
AI =
[ -a22/(-a11*a22+a12*a21), a12/(-a11*a22+a12*a21)]
[ a21/(-a11*a22+a12*a21), -a11/(-a11*a22+a12*a21)]
AE =
[ 1/2*a11+1/2*a22+1/2*(a11^2-2*a11*a22+a22^2+4*a12*a21)^(1/2)]
[ 1/2*a11+1/2*a22-1/2*(a11^2-2*a11*a22+a22^2+4*a12*a21)^(1/2)]
试题解析