f(x) = x + sin((3 * x))
P: (pi / 3, pi / 3)
g = Tangent(P, f)
eq1: y + (2 * x) = 0
P_n: (pi / 3 + (({-3, -2, -1, 1, 2, 3, 4} * 2 / 3) * pi), f(pi / 3 + (({-3, -2, -1, 1, 2, 3, 4} * 2 / 3) * pi)))