DiametriParabola

a = 0.6 (slider from -5 to 5)
l = 4.3 (slider from -5 to 5)
m = 1.7 (slider from -5 to 5)
u = Vector((0, 0), (l, m))
eq1: ((a * l) * x) - m = 0
eq2: (a * x^(2)) - (2 * y) - 4 = 0
A, B = Intersect(eq2, eq1)
f = Tangent(A, eq2)
g = Tangent(B, eq2)
C = Point(yAxis)
h = Line(C, f)
D = Intersect(h, eq1)
E, F = Intersect(eq2, h)