1.
sin(x/2)*cos(x/2)>1/2
1/2sinx-1/2>0
1/2(sinx-1)>0
sinx>1
x∈∅, т.к. sinx∈[-1;1]
2.
cos²(x/2)-sin²(x/2)≥-√3/2
cosx≥-√3/2
x∈[-5π/6+2πn;5π/6+2πn], n∈N
1.
sin(x/2)*cos(x/2)>1/2
1/2sinx-1/2>0
1/2(sinx-1)>0
sinx>1
x∈∅, т.к. sinx∈[-1;1]
2.
cos²(x/2)-sin²(x/2)≥-√3/2
cosx≥-√3/2
x∈[-5π/6+2πn;5π/6+2πn], n∈N