Cos²(π/4+x)=cos²(π/4 -x) -√3cosx
(cosπ/4 cosx - sinπ/4 sinx)² = (cosπ/4 cosx + sinπ/4 sinx)² -√3cosx
(√2/2 (cosx-sinx))² - (√2/2 (cosx + sinx))² +√3cosx=0
(√2/2)² ((cos-sinx)² - (cosx+sinx)²) +√3cosx=0
(2/4) ((cosx-sinx-cosx-sinx)(cosx-sinx+cosx+sinx)) +√3cosx=0
(1/2) (-2sinx * 2cosx) +√3cosx=0
-2sinx cosx +√3cosx=0
cosx (-2sinx +√3) =0
cosx=0 -2sinx +√3=0
x=π/2+πn, n∈Z -2sinx=-√3
sinx=√3/2
x=(-1)^n * (π/3) +πn, n∈Z
Ответ: х=π/2 +πn, n∈Z,
x=(-1)^n * (π/3) +πn, n∈Z.