This list of trigonometric identities includes the factoring formulas near the bottom. A great tool for reference.

This multimedia Learn Alberta math resource looks at how trigonometry is used in making sure that airplanes land safely at airports. The accompanying interactive component gives students practice in using trigonometric ratios, namely...

Twenty problems present a variety of practice working with fundamental trigonometric identities. They are given with each step to the solution cleverly revealed one at a time. You can work each step of the problem then click the "View...

This MathWords.com site lists the equations for all of the trigonometric identities.

This makes for a great handout for students and teachers, alike! A comprehensive list of 47 commonly-used trig identities.

Faced with a large number of trigonometric identities, students tend to try to memorize them all. This site the emphasis is on understanding how the functions work and on memorizing only about a half dozen of them - all the others work...

The University of Saskatchewan provides an explanation of trigonometric identities, including the reciprocal identities, the addition and subtraction formulas with sine and cosine, and the double angle formulas. There are links to...

Resource provides trigonometry formulas for unit circle, reciprocal identities, ratio identities, Pythagorean identities, sum and difference formulas, and double-angle formulas.

A comprehensive guide for learning all about the basics of trigonometry, the various identities-formulas of trigonometry, solved examples, and practice questions.

[Free Registration/Login may be required to access all resource tools.] Solving equations and verifying identities with the sum and difference formulas.

Provides an explanation, examples, and a video lesson all related to trigonometric identities. [2:31]

This resource clearly and thoroughly explains the many types of trigonometric identities. There are example problems solved, problems for the student to attempt, and answers to the student problems.

[Free Registration/Login may be required to access all resource tools.] Simplifying trigonometric expressions using identities

[Free Registration/Login may be required to access all resource tools.] This lesson uses trigonometric identities to prove other identities.

[Free Registration/Login may be required to access all resource tools.] Illustrates identities found from dividing two trigonometric functions.

[Free Registration/Login may be required to access all resource tools.] This concept teaches students to solve word problems using trigonometric ratios.

[Free Registration/Login may be required to access all resource tools.] This concept teaches students to use inverse trigonometric ratios to solve for missing angles in right triangles.

[Free Registration/Login may be required to access all resource tools.] Simplify trigonometric expressions using identities.

Provides trigonometric identities, which include fundamental identities, even-odd identities, addition formulas, double-angle formulas, subtraction formulas, product-sum formulas, and identities for sin squared and cos squared.

[Free Registration/Login may be required to access all resource tools.] Use a calculator to find trigonometric ratios.

[Free Registration/Login may be required to access all resource tools.] This concept teaches students to find trigonometric ratios with a calculator in order to find missing sides of right triangles.

Students explore trigonometry concepts through this collection of definitions, lessons, examples problem-solving steps and strategies, and practice problems. Topics include solving triangles, trigonometric functions, theorems, and the...

Students will define basic terms relating to trigonometry and use trigonometric ratios.

An "identity" is a tautology, an equation or statement that is always true, no matter what. Proving an identity is very different in concept from solving an equation. This resource demonstrates some useful techniques for proving...