Problem

甲、填充題：共 8 題，每題 8 分，共 64 分。請在答案卷上列出題號依序作答。

3. Find the average value of the function $f(x,y)=e^{-x^2}$ over the plane region $R$ where $R$ is the triangle with vertices $(0,0)$, $(1,0)$, and $(1,1)$. Answer : \underline{\quad(1)\quad}