性质:1.(AB)C=A(BC 2k(AB)=(4)B=4(kB) 3.A(B+C)=AB+AC (B+C)A=BA+CA 4.E.A=4 n nxn mxn 5 AminE nxn 5. (KEm)Amxn =kamxn? Amxn (kEn=A 结论:m阶数量矩阵与任意n阶矩阵可交换 上页 圆性质： 1.(AB)C = A(BC) 2.k(AB) = (kA)B = A(kB) 3.A(B +C) = AB + AC (B + C)A = BA+ CA Em Amn = Amn Amn En = Amn 4. , m n n m n m m n m n A kE A kE A kA     = = ( ) 5.( ) , 结论：n阶数量矩阵与任意n阶矩阵可交换