设A=,B为三阶非零矩阵,且AB=O,则r(A)=_______.
因为AB=0，所以r(A)+r(B)≤3，又因为B≠0，所以r(B)≥1，从而有r(A)≤2，显然A有两行不成比例，故r(A)≥2，于是r(A)=2.
,B为三阶非零矩阵,且AB=O,则r(A)=_______.,B为三阶非零矩阵,且AB=O,则r(A)=_______.
