h = 4.2 (slider from -5 to 5, step 0.1)
k = -1 (slider from -5 to 5, step 0.1)
p = 1.5 (slider from -5 to 5, step 0.1)
V: (h, k)
F: (h, k + p)
Directriz: y = k - p
Q = Point(Directriz)
a = Segment(Q, F)
b = LineBisector(a)
Eje: x = h