# 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 a Java applet to allow student interaction
with the various graphs presented. The applet may take a minute or two
to load the first time you open a page that includes it. After that it
should start in a couple of seconds. Note that the applet requires a
standards-compliant copy of the Java VM. The copy that ships with some
versions of MS Internet Explorer is known to give problems in some
situations. If you experience problems, consider obtaining the Sun JVM
or using Netscape or Mozilla rather than MS Internet Explorer.

Each section includes some exercises. 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

- Introduction
- The sine function
- The cosine function
- The tangent function

*Copyright Glen Prideaux, 2003.*

These pages may be
freely copied for non-commercial use.

If you wish to reproduce
these pages elsewhere, you will also need the JSP applet from Key
Curriculum Press.

Click the ? in the bottom right corner of any of
the applets on the page for more information.