>矢量叉乘 XB=A A2 A3 Bb B B =(A2B3-A4B2)e1+(A3B-AB3)e2+(AB2-A2B1)e A×B= ABsin e A×(B+C)=A×B+A×C A×B=-B×A A×A=0➢ 矢量叉乘1 2 3 1 2 3 1 2 3 2 3 3 2 1 3 1 1 3 2 1 2 2 1 3 ( ) ( ) ( ) e e e A B A A A B B B A B A B e A B A B e A B A B e  = = − + − + − A B n  A B AB n  = sin A B C A B A C  + =  +  ( ) A B B A  = −  A A = 0