2sin^2x - 10cos2x = 9 sin2x + 10
помогите решить уравнение

2sin²x - 10cos²x + 10sin²x = 18sinxcosx + 102sin²x - 10cos²x + 10sin²x - 10 - 18sinxcosx = 02sin²x - 10cos²x - 10cos²x - 18sinxcosx = 02sin²x - 18sinxcosx - 20cos²x = 0Разделим на 2cos²x.tg²x - 9tgx - 10 = 0Пусть t = tgx.t² - 9t - 10 = 0t1 + t2 = 9t1•t2 = -10t1 = 10t2 = -1Обратная замена:tgx = -1x = -π/4 + πn, n ∈ Ztgx = 10x = arctg10 + πn, n ∈ Z.