Петр Петров sin(x) = y 3y^2 - 5y - 2 = 0 D = 25 + 24 = 7^2 y1 = (5-7)/6 = -1/3 y2 = (5+7)/6 = 2 - не подходит sin(x) = -1/3 x = (-1)^k arcsin(-1/3) + pik