___ \/ 2 sin(2*x)*cos(x) - cos(2*x)*sin(x) >= ----- 2
-sin(x)*cos(2*x) + sin(2*x)*cos(x) >= sqrt(2)/2
/pi 3*pi\ And|-- <= x, x <= ----| \4 4 /
(pi/4 <= x)∧(x <= 3*pi/4)
pi 3*pi [--, ----] 4 4
x in Interval(pi/4, 3*pi/4)