Hi,

I was wondering whether there was an explicit formula for the following integral:

$$\int_{B_r}\int_{B_r}|x-y|^{-(d-1)} dx dy$$

Here $dx$ and $dy$ is lebesgue measure on $R^d$ and $B_r$ is some ball of radius $r$.

I was able to write down an expression for it using polar coordinates and areas of spherical caps but the thing is nasty.

It seems rather strange that I have never seen a solution to this.