КТО - НИБУДЬ, ПОЖАЛУЙСТА!!!!

2cos^2 x + sin x - 1 = 0 cos x >= 0 x € [300°; 700°] 2 - 2sin^2 x + sin x - 1 = 0 x € [-90° + 360°*n; 90° + 360°*n], n € Z x € [300°; 700°] 2sin^2 x - sin x - 1 = 0 x € [300°; 450] U [630°; 700°] 2sin^2 x - sin x - 1 = 0 sin x = t 2t^2 - t - 1 = 0 D = 9 t1 = (1 - 3)/4 = -1/2 t2 = (1 + 3)/4 = 1 sin x = -1/2 => x = (-1)^(n + 1) * 30° + 180°*n, n € Z sin x = 1 => x = 360°*n, n € Z x = (-1)^(n + 1) * 30° + 180°*n, n € Z x = 360°*n, n € Z x € [300°; 450] U [630°; 700°] x = 330°, 360°, 690° Ответ: 1380