1)x∈[π/4+2πn;3π/4+2πn]
2)cos(4x-π/6)>√3/2
-π/6+2πn<4x-π/6<π/6+2πn<br>-π/6+π/6+2πn<4x<π/6+π/6+2πn<br>2πn<4x<π/3+2πn<br>πn/2x∈(πn/2;π/12+πn/2)
3)1/2sin(2π/3-4x)≥-√3/4
sin(2π/3-4x)≥-√3/2
-π/3+2πn≤2π/3-4x≤4π/3+2πn
-π/3-2π/3+2πn≤-4x≤4π/3-2π/3+2πn
-π+2πn≤-4x≤2π/3+2πn
-π/6+2πn≤x≤π/4+2πn
x∈[-π/6+2πn;π/4+2πn]