# 3b1: sin2t = PN/l 2sint = 2PN/AP = 2PN/(2*AM) ( as AP = AM + MP and AM = MP) = PN/AM So sin2t/2sint = PN/l/PN/AM = AM/l (eqn 1) In triangle AMO, cos t = AM/l = eqn 1 = sin2t/2sint