Part II

The Essentials of Trigonometry

In this part . . .

Trigonometry is a subject that most students cover briefly in geometry. However, pre-calculus expands on those ideas. We begin with a review of angles and how to build the valuable tool known as the unit circle, based on previous knowledge of the special triangles. We examine right triangles and the basic trig functions built in them. Graphing trig functions may or may not be a review, depending on the Algebra II course you’ve taken, so we take the time to establish how to graph the parent graph of the six basic trig functions and then explain how to transform those graphs to get to the more complicated ones.

This part covers the often-feared and seldom-understood formulas and identities for trig functions. We break each identity down into more-manageable pieces. We show you how to simplify trig expressions and then how to solve trig equations for an unknown variable using formulas and identities. Lastly, we cover how to solve triangles that aren’t right triangles using the Law of Sines and the Law of Cosines.