命题1.1设A,B,C均为m×n矩阵,a,b是数,则有 1加法结合律:A+B)+c=A+(B+C 2加法交换律:A+B=B+A 3.A+ m×n =A 4.A+(-A)=0mxm; 5. a(a+b=aA+bB 6.(a+bA=aA+ba 7.(ab)A=a(b4. 上页命题1.1 设A,B,C均为m × n矩阵,a,b是数,则有 1.加法结合律:A B + +) ( C = A + B C + ); 2.加法交换律 : ; 3. 0 ; 4. ( ) 0 ; 5. ( ) ; 6. ( ) ; 7. ( ) ( ). m n m n A B B A A A A A a A B aA bB a b A aA bA ab A a bA × × + = + + = + − = + = + + = + =