Cos 2α + tg α • sin 2α

Question

Cos 2α + tg α • sin 2α

Answer 1

Cos (a)^2 - sin(a)^2 + sin (a)/cos(a) *2sin(a) cos (a) = cos(a)^2 - sin(a)^2 +sin (a) * 2 sin (a) = cos(a)^2 - sin (a)^2 +2sin(a)^2= cos(a)^2 +sin (a)^2 =1