Posted by haifeng on 2016-04-05 16:44:41 last update 2016-04-05 16:44:41 | Answers (0) | 收藏
设 $f(x,y)$, $f'_y(x,y)$ 连续,
\[ \mu(x,y)=\frac{1}{2}\int_{0}^{x}dt\int_{t-x+y}^{-t+x+y}f(t,s)ds \]
证明:
\[ \mu''_{xx}-\mu''_{yy}=f(x,y). \]
