f(x) = (2 / 3 * x^(2)) - (3 * x) + 12 - ln(x + 1)
A = Intersect(f, yAxis, (0, 12))
g = Tangent(A, f)
B: (2.6434, f(2.6434))
h = Tangent(B, f)
C = Intersect(h, g)
α = Angle(B, C, A)