integral

According to the Mean Value Theorem, for a continuous function $f(x)$ in the interval $[a,b]$, there exists a value $\xi$ in this interval such that $\int_{a}^{b} f(x)dx =$

The value of the integral $\oiint_S \vec{r} \cdot \vec{n} \, dS$ over the closed surface S bounding a volume V, where $\vec{r} = x\hat{i} + y\hat{j} + z\hat{k}$ is the position vec...