8 83 LELL=AA.BB=AA+BB& R p & 1 A 2 A 1 B 2 B L1 L2 L E p & & 1 A 2 A 1 B 2 B L1 L2 L & 1 2 1 2 B1B2 = A1A2 +B1B2 L = L L = A A •