A = (1, 0)
B = (3, 0)
f(x) = -1 - 1 / x
a = 0.2 (slider from 0.1 to 5, step 0.1)
g(x) = (x - a^(2) - 2 * a) / a^(2)
M: (a, f(a))
C = Intersect(g, xAxis)
b = Ray(M, C)