1. The problem statement, all variables and given/known data In the figure, point P is at perpendicular distance R = 2.32 cm from a very long straight wire carrying a current. The magnetic field B set up at point P is due to contributions from all the identical current-length elements ids along the wire. What is the distance s to the element making (a) the greatest contribution to field B and (b)10.5% of the greatest contribution? 2. Relevant equations Biot- Savart Law = u0/4pi * (ids*sin(theta))/(r^2) 3. The attempt at a solution I tried to set up an integration using the biot savart law and came up with something along the lines of, u0*i*R/(4pi) = ∫(-inf/inf) ds/(R^2+ s^2)^(3/2) I solved (a) simply because I figured the strongest point of the magnetic field must be at the point closes to point P, the answer was 0, therefore. I don't understand (b), if 0 is the greatest contribution, 10.5% of the greatest contribution would also be 0... Yet it is not.