Posted by Maddie on Tuesday, November 27, 2012 at 11:26pm.
well, you know that siny = 3/5 cos2y = 1 - 2sin^2 y or, you know that tan 2y = 2tany/(1-tan^2 y) and sec^2 2y = 1 + tan^2 2y good way to check your answer.