task/30229370 Упростить выражение
( (sin²(π/2+α)- cos²(α -3π/2) ) / ( tg²(α+ 3π/2) - ctg²(α -π/2) )
решение ( (sin²(π/2+α)- cos²(α -3π/2) ) / ( tg²(α+ 3π/2) - ctg²(α -π/2) ) ⇔
(sin²(π/2+α) - cos²(3π/2 -α ) ) / ( tg²(3π/2+α) - ctg²(π/2- α ) )
(cos²α - sin²α ) / ( ctg²α - tg²α) =
(cos²α - sin²α )* sin²α*cos²α / ( cos⁴α -sin⁴α) =
(cos²α - sin²α )* sin²α*cos²α / ( cos²α - sin²α)*( cos²α + sin²α) =
sin²α*cos²α = (sinα*cosα)² =( (sin2α) / 2)² = 0,25sin²2α .