Windstream
Ojk World of Math: Relationships Between the Functions
This tutorial discusses relationships among all the trig identities. Examples are given on how to apply them to simplify trig expressions and prove identities.
University of Colorado
University of Colorado: Ph Et Interactive Simulations: Trig Tour
Take a tour of trigonometry using degrees or radians! Look for patterns in the values and on the graph when you change the value of theta. Compare the graphs of sine, cosine, and tangent.
University of Saskatchewan (Canada)
University of Saskatchewan: Trigonometric Functions
This site examines the six trigonometric functions from a right triangle point of view. Provides information, examples, and lots of exercises for understanding.
University of Saskatchewan (Canada)
University of Saskatchewan: Trigonometric Identities
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...
Other
Mathway: Trigonometry Formulas
Resource provides trigonometry formulas for unit circle, reciprocal identities, ratio identities, Pythagorean identities, sum and difference formulas, and double-angle formulas.
University of Guelph
University of Guelph: Trigonometry Tutorial
A guide to calculating trigonometric functions.
Cuemath
Cuemath: Cosecant, Secant and Cotangent Functions
Features graphs of the trigonometric functions cosecant, secant, and cotangent. Includes solved examples and practice questions.
Mathematics Archives
Math Archives: Visual Calculus: 47 Trig Identities!
This makes for a great handout for learners and teachers, alike! A comprehensive list of 47 commonly-used trig identities.
Texas Instruments
Texas Instruments: Computing by Degrees!
In this activity, students use the calculator to solve trigonometry problems using sine, cosine, and tangent. They also find inverses of trigonometric functions.
Analyze Math
Analyze Math: Trigonometric Identities
Learners explore trigonometric identities. Definitions of the Pythagorean, reciprocal, tangent, and negative identities are included.
Northeast Parallel Architectures Center, Syracuse University
Npac Reu Program: Trigonometric Functions
This Northeast Parallel Architectures Center of Syracuse University site offers a quick overview of the six trigonometric functions from the standpoint of the unit circle.
Ministry of Education and Universities of the Region of Murcia (Spain)
Ministerio De Educacion Y Ciencia: Funciones Trigonometricas E Inversas
Learn about trigonometric functions and their inverses with this interactive unit.
Wolfram Research
Wolfram Math World: Inverse Trigonometric Functions
A site on inverse trigonometric functions. Contains a definition, a chart showing functions and their domains, formulas, and many links.
University of Saskatchewan (Canada)
Exercises in Math Readiness for University Study: Trig
Read a lesson, look at examples, and try easy, medium, and advanced problems from a variety of trigonometry topics: radian measure of angles, trigonometric functions, trigonometric identities, and modeling with trigonometric functions.
eFunda
Efunda: Trigonometric Functions
Site reviews trigonometric functions and inverse trigonometric functions. Formulas and graphs for both groups of functions are also shared.
Other
Brown Math: Remembering 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...
Other
Karl's Calculus Tutor: Trigonometric Functions
Great application of trig and introduction to the trig functions. Also found here are the Law of Sines and Law of Cosines as well as other trig topics to review.
Math Planet
Math Planet: Algebra 2: Cosines
Defines and explores the law of cosines through examples and a video lesson. [1:41]
Math Planet
Math Planet: Algebra 2: Trigonometry: Trigonometric Identities
Provides an explanation, examples, and a video lesson all related to trigonometric identities. [2:31]
Math Medics
S.o.s. Math: Table of Trigonometric Identities
This tutorial highlights the numerous trigonometric identites (but does not define the basic trigonometric functions).
Math Words
Math words.com: Trig Identities
This MathWords.com site lists the equations for all of the trigonometric identities.
Clark University
Clark University: Dave's Short Trig Course: Summary of Trig Identities
This Clark University page is an excellent reference page for trig identities. It is a little difficult to read so take your time with the formulas. If you remember soh - cah - toa, the other formulas are right here.
CK-12 Foundation
Ck 12: Trigonometry: Proofs of Trigonometric Identities
[Free Registration/Login may be required to access all resource tools.] Simplifying trigonometric expressions using identities
CK-12 Foundation
Ck 12: Trigonometry: Proofs of Trigonometric Identities
[Free Registration/Login may be required to access all resource tools.] This lesson uses trigonometric identities to prove other identities.