设f(x)是以2为周期的函数，其在-1≤x<1上的表达式为

A f(x)处处可导． B f(x)有一个不可导点． C f(x)有两个不可导点． D f(x)有三个不可导点．

A e-1． B e+1． C e^-1． D e^-1-1．

A α，β，γ． B β，γ，α． C γ，β，α． D β，α，γ．

A <img width="78" height="31" src="https://www.beizhujiaoyu.com/uploads/202208/20220503122814_4959.jpg" /> B <img width="78" height="31" src="https://www.beizhujiaoyu.com/uploads/202208/20220503122815_5858.jpg" /> C <img width="79" height="31" src="https://www.beizhujiaoyu.com/uploads/202208/20220503122816_6483.jpg" /> D <img width="78" height="31" src="https://www.beizhujiaoyu.com/uploads/202208/20220503122817_7733.jpg" />

A <img width="453" height="33" src="https://www.beizhujiaoyu.com/uploads/202208/20220503124006_7881.jpg" /> B <img width="439" height="33" src="https://www.beizhujiaoyu.com/uploads/202208/20220503124008_5421.jpg" /> C <img width="453" height="33" src="https://www.beizhujiaoyu.com/uploads/202208/20220503124008_9442.jpg" /> D <img width="439" height="33" src="https://www.beizhujiaoyu.com/uploads/202208/20220503124010_7100.jpg" />

A <img width="105" height="27" src="https://www.beizhujiaoyu.com/uploads/202208/20220503124216_0068.jpg" /> B <img width="188" height="30" src="https://www.beizhujiaoyu.com/uploads/202208/20220503124217_1473.jpg" /> C <img width="79" height="27" src="https://www.beizhujiaoyu.com/uploads/202208/20220503124218_1788.jpg" /> D <img width="138" height="30" src="https://www.beizhujiaoyu.com/uploads/202208/20220503124219_9911.jpg" />

A 设A为三阶非零矩阵，且A²=O，则，r(A)=2． B 设A为m×n矩阵(m<n)，且r(A)=m，则存在可逆矩阵P，使得PA=(E| O)． C 设A为m×n矩阵(m<n)，且r(A)=m ，则存在可逆矩阵Q，使得AQ=(E|O)． D 设A为m×n矩阵(m<n)，则A^TA为正定矩阵．

A 0． B <img width="14" height="27" src="https://www.beizhujiaoyu.com/uploads/202208/20220503123832_7882.jpg" /> C <img width="12" height="27" src="https://www.beizhujiaoyu.com/uploads/202208/20220503123833_3976.jpg" /> D 1．

A θ³． B 2θ³． C 3θ³． D 6θ³．