mit Brennpunkt

https://www.geogebra.org/haftendorn
Haftendorn, Buch (Springer):
Kurven erkunden und verstehen
Kap 7.7.2  S. 217
www.kurven-erkunden-und-verstehen.de

Ha 2017

c: y = (1 / 4 * x^(2))
A = Point(c)
f = Tangent(A, c)
g = OrthogonalLine(A, f)
B_1, C = Intersect(c, g)
M = Midpoint(C, A)
h_1 = Line(M, yAxis)
B = Intersect(c, h_1)
i = Tangent(B, c)
P = Intersect(f, i)
Ortslinie1 = Locus(P, A)
F = Focus(c)
a: 1 / 4
j = OrthogonalLine(A, xAxis)
k = Line(A, F)
F' = Mirror(F, xAxis)
b = false
l = Line(F, i)
α = Angle(B, P, A)
d = false