1. The problem statement, all variables and given/known data Show that the equivalent resistance is Req = 1/2 [(4RtRl + Rt^2)^(.5) + Rt] http://img74.imageshack.us/img74/5905/pingib2.png [Broken] 2. Relevant equations 3. The attempt at a solution So far all I can get is Req = Rt + Rl Rt/(Rt+Rl) from the first three resistors starting from the left. I suppose I could take that and add it to the next branch Rl Rt/(Rt+Rl), but that would appear to go on to infinity as opposed to stopping at a nice number. Does anyone have any hints on finding the eq. resistance?