I am starting to do work in theoretical physics, and as a test, the professor I am working with asked me to estimate the size of a correction to an approximate solution to the BK equation. I am no really sure how to approach this, as I first tried to plug in the approximation, but found that the integral was still unsolvable. I was thinking using something along the lined of the Euler approximation, but I am still a little bit lost. I would appreciate any tips.