# Homework Help: Verifying that electrostatic potential satisfies Poisson's equation

1. Oct 17, 2012

### demonelite123

i'm trying to understand how the electrosatic potential expressed as an integral satisfies poisson's equation. i know that i have to take the laplacian of both sides of (Eq 1.17) page 35 in Jackson.

i understood how jackson took the laplacian of $\frac{1}{\sqrt{r^2 + a^2}}$ but after Eq 1.30 i am completely lost. he took a taylor expansion of p(x') around the point x' = x which i understand to second order is p(x) + (x' - x) * ∇p + (1/2)((x' - x) * ∇)2p.

but i have no idea how he calculated the integral over $\theta$ and $\phi$ to get the answer on the next line.

how would one go about this? is the process straightforward enough that jackson chooses to simply omit it in the text?

2. Oct 18, 2012