向量积设a=(an,an,a)b=(b,b,b,0=(ab d×b=a.a.a a×b|=d| basing b a×b向量积 设 a a = = ( , x y a ,az ),b b (bx ,by ,bz ),θ = (am, ) ， G G G G . x y z x y z b i j k a a a a b b b × = G G G G G a a × = b b sinθ G G G G a G b G a ×b G G θ