Sin2a - tga × ctga = Упростить выр.:

Question

Sin2a - tga × ctga =
Упростить выр.:

Answer 1

Sin2a - tga × ctga =sin2a - 1 = -(1 - sin 2a) = - (sin²a + cos²a - 2sina·cosa) =
= -(sina - cosa)² = -(√2 sin(x - π4))² = - 2sin²(x -  π/4)