Arun
Last Activity: 7 Years ago
Dear student
(Cos theta + sin theta)² / (cos²theta - sin² theta) - (cos theta- sin theta)²/(cos² theta - sin² theta)
= 4 cos theta* sin theta/ cos (2 theta)
= 2 * 2sin (2 theta)/ cos (2 theta)
= 2 tan (2 theta)
Regards
Arun (askIITians forum expert)