Laplace equation in cylindrical coordinates
= Laplace equation in cylindrical coordinates
{c}
In cylindrical coordinates $(r,\theta,z)$, <Laplace's equation> is
$$
\frac1r\frac{\partial}{\partial r}
\left(r\frac{\partial\phi}{\partial r}\right)
+\frac1{r^2}\frac{\partial^2\phi}{\partial\theta^2}
+\frac{\partial^2\phi}{\partial z^2}=0.
$$