сos(p/3-2x)+cos(p/6+2x)=0

2Cosπ/4 Cos(π/6 - 2х) = 0
Сos(π/6 - 2х) = 0
π/6 - 2х = π/2 +  πn,  n Є Z
2x =π/6 -  π/2 -  πn,  n  Є Z
2x = -π/3 -  πn,  n  Є Z
x = -π/6 -  πn/2,  n  Є Z