Cos^2x = 1 - sin^2x
3sinx - 2 + 2sin^2x = 0
t = sinx
2t^2 + 3t - 2 = 0
t = 2, t = 0.5
Подходит только t = 0.5, так sinx <= 1<br>sinx = 0.5
x = π/2 +- π/3 + 2πn, n ∈ Z
-π ≤ π/2 +- π/3 + 2πn ≤ π, Домножим на 6/π
-6 ≤ 3 +- 2 + 12n ≤ 6
-9 ≤ +- 2 + 12n ≤ 3
n = 0
х = π/2 +- π/3
x1 = π/2 + π/3 = 5π/6
x2 = π/2 - π/3 = π/6
Ответ: 5π/6; π/6