Paper 1, Section I, A
Part IB, 2015
Consider a frictionless bead on a stationary wire. The bead moves under the action of gravity acting in the negative -direction and the wire traces out a path , connecting points and . Using a first integral of the Euler-Lagrange equations, find the choice of which gives the shortest travel time, starting from rest. You may give your solution for and separately, in parametric form.