(sin²x/4 + cos²x/4)·(sin²x/4 - cos²x/4) = 1/2
1· (sin²x/4 -cos²x/4) = 1/2
-(cos²x/4 - sin²x/4) = 1/2
cos²x/4 - sin²x/4 = - 1/2
cos (2·x/4) = - 1/2
cos x/2 = -1/2
x/2 = arccos(-1/2) + 2πn или x/2 = - arccos(-1/2) + 2πk
x/2 = (π - π/3) + 2πn x/2 = - (π - π/3) +2πk
x = 4π/3 + 2πn x = - 4π/3 + 2πk