Let
(a) Find AB and BA.
(b) Find A, B, and AB, and verify that Theorem 2.9c holds in this case.
(c) Find BA and compare to AB.
(d) Find (AB) 0 and compare to B' A' .
(e) Find tr(AB) and compare to tr(BA).
(f) Find the eigenvalues of AB and of BA, thus illustrating Theorem 2.12a.