1. The problem statement, all variables and given/known data Consider a general point on the line joining the two wires and a distance d away from the mid-point O. By summing the magnetic field due to currents of magnitude i flowing in both the wires which are non-zero, show that on the line joining the two wires, the magnetic field strength is given by: B= μ iD / π(D2 −d2) 2. Relevant equations (D^2 −d^2) = (D+d)(D-d) ****** a simple trig identity B= μ i / 2π d 3. The attempt at a solution I'm kinda stuck - any pointers on where to start?