1. The problem statement, all variables and given/known data How to calculate the following integral: Integral( 1/ |x-y| dS) where x and y are vectors in R^2, || represents norm. So say x= (x1,x2), y=(y1,y2). Then the integral is [ dS/ sqrt ((y1-x1)^2 + (y2-x2)^2)]. The problem is: I need to integrate this over any plane in R^3. 3. The attempt at a solution So I assume the plane is of the form ax+by+cz+d =0. Then I really have no clue how to proceed.