O = Intersect(yAxis, xAxis)
a = 4 (slider from 0 to 15, step 0.1)
c = 2.3 (slider from 0 to 15, step 0.1)
b: sqrt(a^(2.0) - c^(2.0))
E: x^(2.0) / a^(2.0) + y^(2.0) / b^(2.0) = 1.0
F_1: (c; 0.0)
F_2: (-(c); 0.0)
M = Point(E)
d = Segment(F_2, M)
e = Segment(M, F_1)
f = Segment(F_2, F_1)