```
In [16]:
```from IPython.display import Image

$\nabla f = \frac{1}{r^2}\frac{\partial}{\partial r}(r^2\frac{\partial f}{\partial r}) + \frac{1}{r^2\sin\theta} \frac{\partial}{\partial\theta}(\sin\theta\frac{\partial f}{\partial\theta})+\frac{1}{r^2\sin^2\theta} \frac{\partial^2 f}{\partial\psi^2}$

The variable r is the distannce from the origin and theta is the azimuth angle.