# A Frusterating Double-Integral

## Homework Statement

Integrate:

$$\int \int \frac{1}{[(x_1-x_2)^2+a^2 ]^1^/^2} dx_1 dx_2$$

(The bounds on the first integral are [-L/2, L/2] and the second integral's bounds are the same.)

N/A

## The Attempt at a Solution

I stared at this problem long and hard, and was hoping to use some sort of a trigonometric substitution, but nothing came to mind. I have a suspicion that I might need integral tables to solve this problem, but I might be jumping the gun on this.

I feel like the 'a' variable is throwing a real wrench in the system. If anyone could maybe nudge me in the right direction (if this is solvable without consulting a table) I'd be very appreciative.