Cos^2x = 1 - sin^2x 5 sinx = 3(1 - sin^2x) - 5 5sinx = 3 - 3sin^2x - 5 3sin^2x+5 sinx +2 = 0 sinx = t, -1<=t<=1<br>3t^2 + 5t +2 = 0 t1= -1,значит sinx = -1, x = -пи/2 + 2 пи к t2 = -2/3, значит sin x = -2/3, x = (-1)^n*arcsin(2/3) + пи n