## Basic Trigonometric Functions

Basic Trigonometric functions are concerned with functions of angles, and how they relate to periodic phenomena. Periodic phenomena can be described with mathematical formulas that are defined on the unit circle, which is a circle with radius of one unit.

Read the chapters in our book on the unit circle, pi, sines, and cosines. Then,

choose at least one of the following 3 sites on trigonometry, and comment using the form at the bottom of the page.

Oolong Trigonometry

http://www.teachersfirst.com/20/getsource.cfm?id=4486

http://www.themathpage.com/aTrig/trigonometry.htm

## VIDEO: Basic Trigonometry

Exercises

Read Math:Trigonometry and do the associated exercises.

More Trigonometry practice: http://www.teachersfirst.com/20/getsource.cfm?id=9325

## Sines

What is the Law of Sines?

http://en.wikipedia.org/wiki/Law_of_sines

What are wave forms and why are they important?

http://en.wikipedia.org/wiki/Sine_wave

Why is it that radar uses radians instead of pi? Read Radians to Degrees and Back Again.

## VIDEO: The Law of Sines

Discussion:

How does the sine wave relate to the unit circle? Can you find an example on the Internet?

## Cosines

What is the Law of Cosines? How does it relate to basic trigonometry?

http://www.trigonometry-help.net/law-of-cosines.php

Discussion:

How do cosines relate to the unit circle? Can you find an example on the Internet?

## VIDEO: The Law of Cosines

## Pi

What is Pi, who discovered it, and why is it important?

pi is the ratio of the circumference of a circle to its diameter. It is always denoted with the greek letter named pi. For more information, let us ask Dr. Math about pi.

What else does pi have to do with circles? see The Circle. This is a good review of how circles are used before we go much further into similar mathematics using trigonometric functions instead of circumference, radius, and diameter.

## VIDEO: The Unit Circle

## Real World Trigonometry

How is trigonometry used in the real world? Navigation, engineering, and astronomy are all sciences that rely heavily on trigonometry. Can you find a word problem from another science that uses sines, cosines, radians, the unit circle, or pi? Do not solve the problem, just identify it and bring it to class.

This is a paper and pencil exercise.