(1)axa=0.(:6=0→sin=0) (2)db←→a×b=0.(a≠0,b≠0) (1)d×b=-b×li (2)分配律:(+b)x=x+b×乙 (3)若伪数:()×b=ax(Ab)=(axb向量积符合下列运算规律: (1) a b b a. = − (2)分配律: (a b) c a c b c. + = + (3)若 为数: ( a) b a ( b) (a b). = = 关于向量积的说明: (1) 0. a a = ( = 0 sin = 0) a b (2) // 0. a b = ( 0, 0) a b