a' = 7.7 (slider from 0 to 20)
b' = 3.9 (slider from 0 to 20)
Ellipse: x^(2) / a'^(2) + y^(2) / b'^(2) = 1
A = Intersect(Ellipse, xAxis, 2)
B_{1} = Intersect(Ellipse, yAxis, 2)
C = Intersect(xAxis, yAxis)
a = Segment(C, A)
b = Segment(C, B_{1})