证明V()=0+V 证 (4)+(04,)+( Q(1 o4+04+a4 00 00 a+-la+ A 02 -PV. A+V. A证明  =  +   (   A A A ) ( ) ( ) ( ) ( ) A A A A x y z x y z         = + +    x y z x y z A A A A A A x y z x y z             = + + + + +           =  +     A A 证：