Posted by haifeng on 2022-11-08 16:12:34 last update 2022-11-08 16:12:34 | Answers (1) | 收藏
设 $y=f(x)$ 具有反函数, 其反函数为 $g(x)$. 并且 $g$ 二阶可导, 且满足 $(g'(x))^2=g''(x)$, 证明 $f''(x)+f(x)=0$.