___ cos(x) \/ 3 ------ < -----*cos(x) 2 2
cos(x)/2 < (sqrt(3)/2)*cos(x)
/ / pi\ / 3*pi \\ Or|And|0 <= x, x < --|, And|x <= 2*pi, ---- < x|| \ \ 2 / \ 2 //
((0 <= x)∧(x < pi/2))∨((x <= 2*pi)∧(3*pi/2 < x))
pi 3*pi [0, --) U (----, 2*pi] 2 2
x in Union(Interval.Ropen(0, pi/2), Interval.Lopen(3*pi/2, 2*pi))