Упростить вырожение 4 (cos^2t-2sin^2t-2sintcost)

Может так sin 4t/cos 2t=2sin2tcos2t/cos2t=2sin2t

cos t/cost/2+sint/2 = cos2*t/cost/2+sint/2 = (cost/2+sint/2) (cost/2-sint/2) / cost/2+sint/2=cost/2-sint/2

cos 2t - sin 2t/cos 4t=cos 2t - sin 2t/cos 2*2t=cos 2t - sin 2t / (cos 2t - sin 2t) (cos 2t + sin 2t) =

=1/cos 2t+sin 2t