Question

若f''(x)存在,求函数y=f(x+e^-x)的二阶导数.

Answer 1

y=f(x+e^(-x))

y' = (1-e^(-x))f'(x+e^(-x))

y'' = e^(-x)f'(x+e^(-x)) +(1-e^(-x))^2.f''(x+e^(-x))