2 1 - 2*sin(4*x) < cos (4*x)
1 - 2*sin(4*x) < cos(4*x)^2
/ pi\ And|0 < x, x < --| \ 4 /
(0 < x)∧(x < pi/4)
pi (0, --) 4
x in Interval.open(0, pi/4)