Let a be a 3-order square matrix with eigenvalues of 1,2, - 3, find the eigenvalues of a ^ 2-3a + A ^ - 1 + 2E, and | a ^ 2-3a + A ^ - 1 + 2e |, hope to give the process

Let a be a 3-order square matrix with eigenvalues of 1,2, - 3, find the eigenvalues of a ^ 2-3a + A ^ - 1 + 2E, and | a ^ 2-3a + A ^ - 1 + 2e |, hope to give the process




Let a be a third-order square matrix with eigenvalues of 1,2, - 3, find a Λ 2-3a + a Λ (- 1) + 2e and|a Λ 2-3a + a Λ (- 1) + 2E|


The first question is to find eigenvalues
The eigenvalues of a are 1,2, - 3
Then, the eigenvalues of a Λ 2-3a + a Λ (- 1) + 2E are
1-3+1+2=1
4-6+1/2+2=1/2
9+9-1/3+2=59/3
The value of determinant = the product of eigenvalues
|A∧2-3A+A∧(-1)+2E|=1×(1/2)×(59/3)=59/6



Let λ be the eigenvalue of square matrix A of order n, and prove that the eigenvalue of α + 2E is λ + 2


If λ is the eigenvalue of square matrix A of order n, then:
Ax = λ x, where x is the eigenvector corresponding to λ
Investigation of (a + 2e) x
(A+2E)x = Ax +2Ex
=λx + 2x
=(λ+2)x
So the eigenvalue of a + 2E is λ + 2, and we can see that the corresponding eigenvector remains unchanged