a·a=a (2)a·b=0a⊥b (1)交换律:ab=b; (2)分配律:(d+b)c=d+bc; (3)若为数:()b=a(b)=2(a.b) 若、为数:(n)、(b)=A(a·b关于数量积的说明: (2) a b = 0 a b. (1) | | . ⊥ 2 a a a = 数量积符合下列运算规律: (1)交换律: 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), = = 若 、 为数: ( a) ( b) (a b). =