ABSTRACT
The study of functions and modeling is now a cornerstone in the secondary school curriculum. Students begin studying the concept of function in elementary school and continue throughout their secondary school careers. This chapter explores a bit of the evolution of functions, how they are used to model practical problems, how practical problems are solved by studying data and fitting them to curves known as regression curves or best fit curves. It discusses a special type of modeling, modeling with recursive relations, something that is very useful in real-life applications. Using the historical notion of function, the postage that one pays on a package is a function of the weight of the package, since the postage depends on the weight. The weight is the independent variable, and the postage is the dependent variable. In secondary school, some of the more important graphs studied were those of linear functions, quadratic functions, exponential functions, polynomial functions, and root functions.
