cos(π/2-4x)>-1/2;
sin4x>-1/2;
4x∈(-π/6+2πn; 7π/6+2πn). n∈Z.
x∈(-π/24+πn/2;7π/24+πn/2). n∈Z.
ctg(2x-π/4)>1/√3;
πn<2x-π/4<π/3+πn. n∈Z.</em>
π/8+πn/2
x∈(π/8+πn/2; 7π/24+πn/2). n∈Z.
tg(2x+π/3)≥-1/√3;
-π/2+πn<2x+π/3≤-π/6+πn. n∈Z.</em>
-5π/12+πn/2
x∈(-5π/12+πn/2; -π/3+πn/2]. n∈Z.