变化规律(1)转置后秩变大(2)r(A)<=min(m,n),A是m*n型矩阵(3)r(kA)=r(A),k不等于0(4)r(A)=0 <=> A=0(5)r(A+B)<=r(A)+r(B)(6)r(AB)<=min(r(A),r(B))(7)r(A)+r(B)-n<=r(AB)
查看答案
P,Q为可逆矩阵, 则 r(PA)=r(A)=r(AQ)=r(PAQ)
A. 对
B. 错
You had better book rooms at the hotel in advance ______ you should find no room on your arrival.
A. so that
B. even if
C. in case
D. now that
_______ computer games bring us a lot of pleasure, I don't think it wise to spend too much money and time on them.
A. Because
B. As
C. While
D. If
_____ you are unable to deal with it, perhaps we should ask someone else for help.
Although
B. While
C. Since
D. Unless