Problem 3
Basic linear algebra related to eigenvalues
Let
A = (1 0; 0 -1), and B = (0 1; 1 0).
State if each of the following is TRUE or FALSE for the above matrices A and B. In each case, you must provide reasons/hand calculations to support your answer.
(a) The matrices A and B have same eigenvalues.
(b) Eigenvalues of AB are the product of the respective eigenvalues of A and the eigenvalues of B, that is, λ_i(AB) = λ_i(A)λ_i(B), for i = 1, 2.
(c) λ_i(A + B) = λ_i(A) + λ_i(B), for i = 1, 2.
(d) Consider the elementwise product A ⊙ B (this is same as the MATLAB "dot star" operation A .* B). Then λ_i(A ⊙ B) = 0, for i = 1, 2.
(e) Consider the Kronecker product A ⊗ B = (a_11 B a_12 B; a_21 B a_22 B). Then |λ_i(A ⊗ B)| = 1, for i = 1, ..., 4.