Let A and B be n n matrices with eigenvalues and , respectively. (a) Give an example to show that +

Let A and B be n × n matrices with eigenvalues λ and μ, respectively.
(a) Give an example to show that λ + μ need not be an eigenvalue of A + B.
(b) Give an example to show that λμ need not be an eigenvalue of AB.
(c) Suppose λ and μ correspond to the same eigenvector x. Show that, in this case, λ + μ is an eigenvalue of A + B and λμ is an eigenvalue of AB.