Question

函数y=cos(1+x²)的导数是(    )

A.2xsin(1+x²)           B.-sin(1+x²)       C.-2xsin(1+x²)        D.2cos(1+x²)

Answer 1

解析：y′=［cos(1+x²)］′·(1+x²)′=-sin(1+x²)·2x=-2xsin(1+x²).

答案：C