1. The problem statement, all variables and given/known data Find the length of the path over (2 cos t - cos 2t, 2 sin t - sin 2t) 0<=t<=(pi/2) 2. Relevant equations sin^(2) x = (1-cos 2x)/2 3. The attempt at a solution I have worked my way thru the problem and I have arrived at 2 (sq root 2) antiderivative (sq root (1-cos t)), but I'm not sure how this coverts into the relevant equation above? Thanks in advance!