A. 高阶无穷小量                                               B. 低阶无穷小量

C. 同阶但不等价无穷小量                                 D. 等价无穷小量

11. 已知函数 f(x)=   ，则 f(x) 在 x=0 处 (         )

A. 间断                                                             B. 导数不存在

C. 导数 f’(0)=-1                                                D. 导数 f’(0)=1

12. 设 f(x)=sin(3x+ ) ，则 =(         )

A.-3                       B.3                                      C.0                        D.-1

13. 设 f(x)=e^x+2, 则 f’(x+2)=(         )

A.e^x+2                                         B.e^x+4                                                                     C.2e^x+2                                     D.2e^x+4