Find divergence of vector field

Question

The vector field $\textbf{F}$ is a function of the position vector $\textbf{r}$

$$\textbf{F}(\textbf{r}) = \frac{\textbf{r} - \textbf{r}_0}{\|\textbf{r} - \textbf{r}_0\|}$$

What would be the divergence $\nabla\cdot\textbf{F}$? I'm assuming that $\textbf{r}= \langle x,y,z \rangle$

Answer 1

$\displaystyle \frac{1}{\parallel r-r_0\parallel}\nabla\cdot(r-r_0)+(r-r_0)\cdot\nabla\frac{1}{\parallel r-r_0\parallel}$