Question

Как упрощается данное выражение?

Answer 1

$frac{1-2Sin^{2}alpha}{2tg(45^{o}-alpha )*Cos^{2}(45^{o}-alpha} =frac{Cos2alpha }{frac{2Sin(45^{o}-alpha)}{Cos(45^{o}-alpha)}*Cos^{2}(45^{o}-alpha)}= frac{Cos2alpha }{2Sin(45^{o}-alpha)Cos(45^{o}-alpha)} =frac{Cos2alpha }{Sin(90^{o}-2alpha)}=frac{Cos2alpha }{Cos2alpha }=1$