7. 點(diǎn)從點(diǎn)出發(fā)，按逆時(shí)針方向沿周長(zhǎng)為的圖形運(yùn)動(dòng)一周，兩點(diǎn)連線的距離與點(diǎn)走過的路程的函數(shù)關(guān)系如圖，那么點(diǎn)所走的圖形是（   ）

A.    B. ,     C.   D. ,

6.若函數(shù)的導(dǎo)數(shù)是則函數(shù) (0<a<1)的單調(diào)遞減區(qū)間是(   )                                                                                                                                                                                                                                                                      

5.若直線mx+ny=4和圓O:沒有交點(diǎn),則過點(diǎn)(m,n)的直線與橢圓的交點(diǎn)個(gè)數(shù)為(   )

 A.至多一個(gè)         B.2個(gè)         C.1個(gè)            D.0個(gè)

4.甲、乙、丙、丁、戊5人站成一排，要求甲乙均不與丙相鄰，不同排法種數(shù)有  （  ）

 A. 72            B.54                 C.36            D.24

  C. 且                D. 且

A. 且               B. 且

3.直線與平面滿足,,那么必有 (    )

A.          B.                  C.           D.1

2.與復(fù)數(shù)的積為1的復(fù)數(shù)的虛部為                      (    )