Trigonometric Functions as Projections

These web pages provide a series of interactive lessons to introduce the concept of trigonometric functions as projections based on the unit circle. They are not intended to be used instead of a text book, but as a supplement to give students another way of exploring the subject material.

These pages make use of JavaScript interactives built with JSXGraph to allow student interaction with the various graphs presented.

Most pages includes some brief exercises to check your understanding. Answers to the exercises are provided, and students should check their work before progressing. Whenever you get an answer incorrect, make sure you take the time to understand where you went wrong. Incorrect answers can be a great opportunity to learn if you do this.

Some of the answer pages include additional teaching points.

The lessons

1. Introduction
2. The sine function
   • The sine function as a projection
   • The period of the sine function
3. The cosine function
   • The cosine function as a projection
   • The period of the cosine function
   • Similarity between sine and cosine
4. The tangent function
   • The tangent function as a projection
   • The period of the tangent function

Copyright Glen Prideaux, 2003, 2021.
These pages may be freely copied for non-commercial use.