>矢量与标量乘积 aA=aAe+aAe,+aa a(A+ B)=aA+ab >矢量点乘 A B=AB+A B2+A3 B3 A·B= ACoS6 A·B=B·A B A B+C)=A.B+A C A.A=2➢ 矢量与标量乘积 ➢ 矢量点乘 a A B aA aB ( ) + = + 1 1 2 2 3 3 aA aA e aA e aA e = + + A B A B A B A B 1 1 2 2 3 3  = + + A B B A  =  A B C A B A C  + =  +  ( ) 2 A A A  = A B AB  = cos A B 