f_2 = 5
f_1 = 6
S = Intersect(xAxis, yAxis)
H: (f_1, 0)
c = Circle(S, H)
D = Point(c)
I: (f_2, 0)
d = Circle(S, I)
E = Point(d)
F_2 = Vector(S, E)
F_1 = Vector(S, D)
α = Angle(F_2, F_1)
a = Line(D, F_2)
b = Line(E, F_1)
F = Intersect(a, b)
F_R = Vector(S, F)
p_2 = Segment(D, F)
p_1 = Segment(E, F)
f_R: sqrt(F_R F_R)