已知矩阵，若下三角可逆矩阵P和上三角可逆矩阵Q可使得PAQ为对角矩阵，则P，Q可以分别取(  )．

A 低阶无穷小 B 等价无穷小 C 高阶无穷小 D 同阶但非等价无穷小

A 连续且取得极大值 B 连续且取得极小值 C 可导且导数为零 D 可导且导数不为零

A (e，+∞) B (0，e) C <img width="50" height="33" src="https://www.beizhujiaoyu.com/uploads/202208/20210429182859_7106.jpg" title="" align="" alt="" /> D <img width="80" height="33" src="https://www.beizhujiaoyu.com/uploads/202208/20210429182900_1950.jpg" title="" align="" alt="" />

A dx+dy B dx-dy C dy D -dy

A 2，0 B 1，1 C 2，1 D 1，2

A α₂+α₃+α₄+kα₁ B α₁+α₃+α₄+kα₂ C α₁+α₂+α₄+kα₃ D α₁+α₂+α₃+kα₄

A 若P(A|B)=P(A)，则P(A|<img width="24" height="42" src="https://www.beizhujiaoyu.com/uploads/202208/20210429182813_8386.gif" />)=P(A) B 若P(A|B)>P(A)，则P(<img width="24" height="42" src="https://www.beizhujiaoyu.com/uploads/202208/20210429182815_4293.gif" />|<img width="24" height="42" src="https://www.beizhujiaoyu.com/uploads/202208/20210429182813_8386.gif" />)>P(<img width="24" height="42" src="https://www.beizhujiaoyu.com/uploads/202208/20210429182815_4293.gif" />) C 若P(A|B)>P(A|<img width="24" height="42" src="https://www.beizhujiaoyu.com/uploads/202208/20210429182813_8386.gif" />)，则P(A|B)>P(A) D 若P(A|A∪B)>P(<img width="24" height="42" src="https://www.beizhujiaoyu.com/uploads/202208/20210429182815_4293.gif" />|A∪B)，则P(A)>P(B)

A <img width="250" height="47" src="https://www.beizhujiaoyu.com/uploads/202208/20210429182912_1950.jpg" /> B <img width="341" height="47" src="https://www.beizhujiaoyu.com/uploads/202208/20210429182912_4344.jpg" /> C <img width="251" height="47" src="https://www.beizhujiaoyu.com/uploads/202208/20210429182914_4449.jpg" /> D <img width="341" height="47" src="https://www.beizhujiaoyu.com/uploads/202208/20210429182914_6324.jpg" />

A <img width="24" height="62" src="https://www.beizhujiaoyu.com/uploads/202208/20210429182831_9956.gif" /> B <img width="22" height="62" src="https://www.beizhujiaoyu.com/uploads/202208/20210429182916_9293.gif" /> C <img width="24" height="62" src="https://www.beizhujiaoyu.com/uploads/202208/20210429182837_3512.gif" /> D <img width="22" height="62" src="https://www.beizhujiaoyu.com/uploads/202208/20210429182918_9136.gif" />