d0: y = 0
a = 2 (slider from -5 to 5)
k = 6 (slider from -5 to 20)
F: (0, a)
lieuP: sqrt(x^(2) + (y - a)^(2)) + abs(y) = k
P = Point(lieuP)
perpendP = OrthogonalLine(P, d0)
H = Intersect(perpendP, d0)
h = Segment(P, H)
pf = Segment(P, F)
sP: k - h - pf
b: k
d1: y = b
courbe1 = Parabola(F, d1)
d2: y = (-b)
courbe2 = Parabola(F, d2)
A = Intersect(perpendP, d1)
B = Intersect(perpendP, d2)
pa = Segment(P, A)
pb = Segment(P, B)
α = 0.01 (slider from -0.5 to 0.5, step 0.01)
x0: sqrt(k^(2) - a^(2))
S1_{1}: 0
S1 = Intersect(courbe1, yAxis, 1)
F1 = Intersect(d1, yAxis)
S2 = Intersect(courbe2, yAxis, 1)
F2 = Intersect(d2, yAxis)