矩阵乘法的运算规律2.(结合律)(1)(AB)C = A(BC)(2)A(B+C) = AB+ AC（分配律）(B+C)A= BA+CA(3)A.E.=E.Ax=AXI(4)A0 = 0,0A=0a,ba-(5)b84.2矩阵的运算A§4.2 矩阵的运算 2．矩阵乘法的运算规律 (1) ( ) ( ) AB C A BC = (2) ( ) A B C AB AC + = + (3) A E E A A s n n s s n s n    = = ( ) B C A BA CA + = + (5) 1 1 1 1 n n n n a b a b a b a b           =           (结合律) （分配律) (4) 0 0, 0 0 A A = =