Ответ: 6cos²x + 13*2sinxcosx = — 10(sin²x + cos²x)6cos²x + 26sinxcosx = — 10sin²x — 10cos²x6cos²x + 10cos²x + 26sinxcosx + 10sin²x = 0 16cos²x + 26sinxcosx + 10sin²x = 0 /:28cos²x + 13sinxcosx + 5sin²x = 0 /:cos²x ≠ 0 5tg²x + 13tgx + 8 = 0 tgx = t 5t² + 13t + 8 = 0 D = 169 — 160 = 9t1 = ( — 13 + 3)/10 = — 10/10 = — 1t2 = ( — 13 — 3)/10 = — 16/10 = — 8/51) tgx = — 1x = — pi/4 + pik,k ∈Z2) tgx = — 8/5x = — arctg(8/5) + pik, k ∈Z
Источник znanija.site