KI K2 KI KM K2 KI K2 KI K2 K3 KI K2 K3 f(KM)=(KlK2+K2KI+KlK2)(K1+K2+K3+KIK2K3) =(K1+K1K2)(K1+K2+K3+K1+K2+K3 (K1+K2)1 =K1+K21 2 ( 1 2)1 ( 1 1 2)( 1 2 3 1 2 3) ( ) ( 1 2 2 1 1 2)( 1 2 3 1 2 3) K K K K K K K K K K K K K f KM K K K K K K K K K K K K = + = + = + + + + + + = + + + + +