Dave’s Short Trig Course
You should already be familiar with algebra and geometry before learning trigonometry.
Frequently Asked Questions About Trigonometry
Q: What is trigonometry?
A: Trigonometry is the study of how the sides and angles of a triangle are related to each other. Interactive site showing you how sides and angles in a triangle relate.
High School Trigonometry
Ask Dr. Math a trig question or browse the answers he’s already given to other students.
History and Uses of Trigonometry
My son asked me the other day what in the world he would ever use trig for. Here are some answers.
SOS Math: Trigonometry
Trigonometry is the art of doing algebra over the circle. So it is a mixture of algebra and geometry.
Triangles, Circles, and Waves (oh my!)
An Overview of Trigonometry by Kenny Felder. This sheet is meant as a guide to help you review trigonometry.
Trig Help – Trigonometry Online Video Lessons
Visual help with trigonometry, trig functions, right triangles, radians, identities, formulas, and graphing.
Trig without Tears
How to remember trigonometric identities. I believe it is much more effective (and, in the long run, much easier) to understand thoroughly how the trig functions work, memorize half a dozen formulas, and work out the rest as needed.
The trigonometric functions are very important in technical subjects like science, engineering, architecture, and even medicine. You will come across trig functions all the time and you are encouraged to learn them well! Bored? Try the Math Games near the bottom of this page.
I am a theoretical physical chemist. Chemists use trigonometry routinely to interpret spectroscopic probes of molecules and use them to figure out molecular structures. Without trigonometry we would know very little about chemistry!
If you would just like one page to print out with all the trig definitions, this is your page. This site also has an iPhone app for trig and other calculations for a small fee.
When you understand this animated diagram, you shall understand the sin(x).
Uses of trigonometry
Knowledge of nearly nothing beyond trigonometry itself is enough to make clear the nature of some of the applications of trigonometry to such endeavors as navigation, land surveying, building, and the like, but that impression is misleading in that it fails to indicate the nature and enormous variety of the other scientific applications and other uses of trigonometry.
Expressions, solving right triangles.