Numerical method for approximating a function

In this paper we present the stages of implementing a numerical method to approximate a function. In order to achieve the objective of this work, we consider a function defined on an interval [a,b] and select three nodes from within the assumed interval. At these three chosen points, we will also know the values of the function at these points and also the values of the first order derivatives at the three points. An interpolation polynomial, of minimum degree, with the assumed nodes will be obtained.