# Finding the Control Point in a bezier curve

This is a basic (and probably a stupid) question, math is not my forte and I don't know much about math, in this site:

http://www.ams.org/samplings/feature-column/fcarc-bezier

in the bezier curves column, specifically in the cubic bezier curve there are 4 points in a line namely p0 p1 p2 and p3.

In my case, I need to find the 2 control point in a line with a specific start and end point.

I can't understand where did the p1 and p2 came from.

and also, where could I get the tangent?

Please know that I am not a mathematician, I have a basic math knowledge and I'm poor at algebra and other kind of math, so please understand and explain as simple as you could do, I would appreciate it so much.

I have searched and found some links here as well, but I feel like I need a simpler answer than those (stupid right?) T.T

(I am trying to understand bezier curve better so I could make a function of that in objective c with specific number of points. And I'm assuming that the formula in that site will be helpful for my function as well.)

• What exactly are you wondering about? Do you have some function that you are trying to approximate with a curve? Or are you just trying to understand bezier curves better? Are you looking for the formula for Bezier curves? – Alan Wolfe Aug 3 '15 at 5:20
• Oh sorry for not specifying, I am actually trying to make a function for making a cubic bezier curves with specific number of points via object c, but I can't understand bezier curves so I am trying to understand it better so I could make a function for that using uibezierpath in objective c – jane Aug 3 '15 at 5:23

Bezier curves pass through the first and last control point, but in general do not pass through the others.

Your best bet for understanding Bezier curves to use them in a program is to start out by playing with them and seeing how they work and how moving control points affects the curve.