3. The Cayley-Hamilton Theorem states that a second tensor A satisfies its own characteristic equation, A + A A + IIIA = 0 You may In=tr(4) 2 ! = =[(tra) tr (43)] . find this useful in proving the following. II = [2tr (4) 3tr (A) tr (4) + (trA)] IIIA i.e. : the principal invariants I, II, III can be written in terms of an alternate set of invariants.