I am trying to answer all the odd problems at the end of the chapter and I can't seem to get one of them. A long, current-carrying wire is oriented vertically; next to it is drawn a square whoe area lies in the same plane as the wire. Using the distances indicated, find the magnetic flux through the square. The figure shows a long wire with I pointing upward, and a square at a distance d from the wire. Each side of the square is of length a. The answer is (u0=4pi*10^-7*I*a)/2pi * ln[a+d/a] Please Help!