-sin(x) cos(x) >= -------- ___ \/ 1
cos(x) >= (-sin(x))/sqrt(1)
/ / 3*pi\ /7*pi \\ Or|And|0 <= x, x <= ----|, And|---- <= x, x <= 2*pi|| \ \ 4 / \ 4 //
((0 <= x)∧(x <= 3*pi/4))∨((7*pi/4 <= x)∧(x <= 2*pi))
3*pi 7*pi [0, ----] U [----, 2*pi] 4 4
x in Union(Interval(0, 3*pi/4), Interval(7*pi/4, 2*pi))