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。

5. Find the volume of the solid bounded above by the surface $z=f(x,y)$ and below by the plane region $R$, where $f(x,y)=\ln x$ and $R$ is bounded by the graphs $y=2x$ and $y=0$ from $x=1$ to $x=3$. Answer : \underline{\quad(1)\quad}