ashin
Sep 16, 2011, 07:19 PM
Sec(a)^2+cot^2(90-a)=2cosec^2(90-a)-1
Unknown008
Sep 17, 2011, 08:47 AM
Please, do show us what you have tried. Remove all the compound angles to put everything in terms of a. Then, converting everything to sine and cosine is usually much easier.