Introduction

This is the most important unit in the year, because it introduces many of the major “themes” that will run through the entire class. These themes include:

• What is a function?
• How are functions used to model things in the real world?
• What does it mean for two functions to be “equal”?
• How does a functional description $f\left(x\right)=3x$ relate to a graph?

More detailed topics include the vertical line test (the “rule of consistency”), the “dependent” and “independent” variables, domain and range, composite functions, and inverse functions.

Also included in this unit is a quick review of graphing lines. It is assumed that students are mostly familiar with this topic from Algebra I.