向量的加法符合下列运算规律 (1)交换律:a+b=b+l (2)结合律:a+b+C=(+b)+C=a+(b+C (3)零向量性质:+0=0+a=a (4)负向量性质:a+(-a)=(-a)+a=0. 2]减法a-b=a+(-b . b wa+b C=d+(-b) =a-b b向量的加法符合下列运算规律: (1)交换律: a b b a. + = + (2)结合律: a b c a b c + + = ( + ) + a (b c). = + + ( ) ( ) 0. a + −a = −a + a = [2] 减法 a b a ( b) − = + − a b b − b c − a b c a b = − a b = + (− ) + a b a − b (3)零向量性质: (4)负向量性质: a 0 0 a a. + = + =