V (x_0, y_0)

P (x, y)

F (0, 1/4)

Tangente en P

x - x_0

y - y_0

1/4

V = (2, 1)
y0: y(V)
i = OrthogonalLine(V, xAxis)
F = Point(i)
a0: y(F) - y0
x0: x(V)
a = If(abs(a0) > 0.02, 1.0 / (4.0 * a0), sgn(a0) / 0.08)
e: a * (x - x0)^(2.0) - (y - y0) = 0.0
P = Point(e)
F_1: (0.0, 1.0 / (4.0 * a))
p: y(F_1)
D: (x(P), y0 - 1.0 / (4.0 * a))
N: (x(P), y0)
j: y = y0
b1 = Segment(F, V)
directriz = Line(2.0 * V - F, Vector[OrthogonalVector[Vector[F, V]]])
f = Segment(F, D)
d = LineBisector(F, D)
g = Segment(P, (x0, y(P)))
h = Segment(P, (x(P), y0))
M: ((x(P) + x0) / 2.0, y0)
c1 = Segment(N, D)
polígono1: {Polygon[N, M, P]}
b: -2.0 * a * x0
x00: round(100.0 * x0) / 100.0
A: (x0, y(Corner[4.0]) - 0.1)
y00: round(100.0 * y0) / 100.0
texto1: "y\;=\;" + (If[a ≟ 1.0, "", If[a ≟ -1.0, "-", "" + a]]) + (If[x00 ≟ 0.0, "\;x^2", "\;(x"]) + (If[x00 ≟ 0.0, "", If[x00 > 0.0, "-\;" + (abs(x00)), "+\;" + (abs(x00))]]) + (If[x00 ≟ 0.0, "", ")^2"]) + (If[y00 ≟ 0.0, "", If[y00 > 0.0, "+\;" + (abs(y00)), "-\;" + (abs(y00))]])
c = Segment(F - (1.0 / (2.0 * a), 0.0), F + (1.0 / (2.0 * a), 0.0))