2,3-|||-练习(2018,2,3 )设A,B为n阶矩阵,记r(X)为矩阵X的秩,(X Y)-|||-表示分块矩阵,则-|||-(A) (A AB)=r(A). (B) (A BA)=r(A).-|||-(C) (A B)=max r(A), r(B)). (D) (A B)=r((A)^T (B)^T).