# Chapter 7: Trigonometric Functions and their Derivatives

## Introduction

We begin with a brief review of plane geometry. We then introduce the sine function, and then the notion of the
vector of a line segment and the wonderful things vectors tell us. Finally we review trigonometry find the
derivatives of trigonometric functions.

This chapter is a review of all you should know about plane geometry trigonometry and much more. I am sure you
have seen the first half of it before so you can whiz through it.

Starting with 7.1b you may find new information worth knowing. What is relevant to calculus is the last section
on derivatives of trigonometric functions.