Figure 5-4. Quadratic
Like the quadratic interpolator, the cubic interpolator is based on a polynomial expression. Cubic
functions can produce more complex curves than quadratic functions, and are characterized by having a
vertical point of inflection. That is to say, they go up, then down, then back up again.
Cubic functions are of the form.
ax 3 + bx 2 + cx + d = 0