c = 1.1 (slider from 0 to 5, step 0.1)
a = 29.321531433504735 (slider from 0 to 31.41592654, step 0.1308996938995747)
b = 1.9 (slider from 0 to 5, step 0.1)
g(x) = (b * sin(x + a))
f(x) = (c * sin(x - a))
sumfg(x) = f(x) + g(x)
fint(x) = If[0 ≤ x ≤ 20,f]
gint(x) = If[0 ≤ x ≤ 20,g(x)]
sumfgint(x) = If[0 ≤ x ≤ 20,sumfg(x)]
d = Segment((20, 0), (20, g(20)))
e = Segment((0, 0), (0, f(0)))