Question

曲线y=x*e^(-x)的拐点?

Answer 1

求二阶导数可以判断凹凸区间；二阶导数为零且在两侧异号的点,即是拐点.f'(x)=e^[(-1/2)x )](-x),f''(x)=e^[(-1/2)x )](-x)