Solve  \; the \;  inequation:  \; cos^2(x)>=1/4

step 1

step 2

step 3

f(x) = cos(x)^(2)
g(x) = 1 / 4
A = Intersect(f, g, (-5.235987755983028, 0.250000000000034))
B = Intersect(f, g, (-4.188790196977124, 0.2500000067630233))
C = Intersect(f, g, (-2.0943951023931975, 0.2500000000000018))
D = Intersect(f, g, (-1.0471975511965945, 0.2500000000000028))
E = Intersect(f, g, (1.0471975511890221, 0.25000000000656064))
F = Intersect(f, g, (2.0943951039492537, 0.25000000134758593))
G = Intersect(f, g, (4.1887902047863905, 0.25000000000000044))
H = Intersect(f, g, (5.235987762854786, 0.2500000059511512))
I = Intersect(f, g, (7.330382858376184, 0.25000000000000056))
J = Intersect(f, g, (8.377580409572783, 0.2500000000000008))
a, K = LookforXcoordinateofpointofintersectionoftwofunctions(f, g, A)
b, L = LookforXcoordinateofpointofintersectionoftwofunctions(f, g, B)
c, M = LookforXcoordinateofpointofintersectionoftwofunctions(f, g, C)
d, N = LookforXcoordinateofpointofintersectionoftwofunctions(g, f, D)
e, O = LookforXcoordinateofpointofintersectionoftwofunctions(f, g, E)
h, P = LookforXcoordinateofpointofintersectionoftwofunctions(f, g, F)
i, Q = LookforXcoordinateofpointofintersectionoftwofunctions(f, g, G)
j, R = LookforXcoordinateofpointofintersectionoftwofunctions(f, g, H)
k, S = LookforXcoordinateofpointofintersectionoftwofunctions(f, g, I)
l, T = LookforXcoordinateofpointofintersectionoftwofunctions(f, g, J)
m = false
n = false
o = false

Tool: Look for X coordinate of point of intersection of two functions (command LookforXcoordinateofpointofintersectionoftwofunctions)
Input: f, g, A
Output: d, D

f(x) = cos(x)^(2)
g(x) = 1 / 4
a = OrthogonalLine(A, xAxis)
D = Intersect(a, xAxis)
d = Segment(A, D)