___ \/ 2 cos(t) <= ----- 2
cos(t) <= sqrt(2)/2
pi 7*pi [--, ----] 4 4
x in Interval(pi/4, 7*pi/4)
/pi 7*pi\ And|-- <= x, x <= ----| \4 4 /
(pi/4 <= x)∧(x <= 7*pi/4)