CHAPTER SIX - FUNCTIONS

Abstract

The concept of a function has been developed as a means of organizing and assisting in the study of relationships. As graphs are powerful means of exhibiting relationships, this chapter discusses the Cartesian or rectangular coordinate system. The system of real numbers can be associated with points on the real number line, that is, it can be seen that there is a one-to-one correspondence between the system of real numbers and points on the real number line. An analogous way to handle points in a plane can be developed; it is called Cartesian or rectangular coordinate system. The Cartesian coordinate system provides a means of drawing a picture or graph of an equation in two variables. In general, the graph of an equation in two variables x and y means the set in the plane of all points P(x, y), whose coordinates (x, y) satisfy the given equation. The chapter describes a function and presents a number of ways of viewing the function concept. It also explores a few special types of functional relationships—increasing and decreasing functions.