sin 2x - 2·cos 2 · sin x + cos x - cos 2 = 0
2·sin x · cos x - 2·cos 2 · sin x + (cos x - cos 2) = 0
2·sin x · (cos x - cos 2) + (cos x - cos 2) = 0
(2·sin x + 1)(cos x - cos 2) = 0
2·sin x + 1 = 0 или cos x - cos 2 = 0
1) sin x = -0,5; x = -π/6 + 2πk или x = 7π/6 + 2πm, k,m∈Z
2) cos x = cos 2; x = 2 + 2πn, n∈Z
Сумма корней:
-π/6 + 2πk + 7π/6 + 2πm + 2 + 2πn = π + 2 + 2π(k + m + n) = π + 2 + 2πl, l∈Z
