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...
CK-12 Foundation
Ck 12: Geometry: Inverse 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.
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...
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.
Math Is Fun
Math Is Fun: Trigonometric Identities
A good introduction to trigonometric identities, equations that are always true for a right triangle and require knowledge of the functions sine, cosine, and tangent.
University of Vienna (Austria)
Univ of Vienna: Trigonometric Functions
An interactive tool to discover how the trig functions came to be. Applets are used in this interactive learning tool. Examples exercises are also given.
Varsity Tutors
Varsity Tutors: Hotmath: Practice Problems: Trigonometric Functions
Hotmath provides 24 practice problems relating to trigonometric functions. Each of the practice problems include a step-by-step guide for solving their function.
Khan Academy
Khan Academy: Trigonometry: Evaluate Inverse Trig Functions
Given a sine, cosine, or tangent value, find the principle angle that has this value. In other words, find the arcsine, arccosine, or arctangent of that value. Students receive immediate feedback and have the opportunity to try questions...
Other
Chat: Inverse Trig Functions [Pdf]
This site is a presentation that discusses how to graph inverse trigonometric functions. Topics included on the presentation are inverse sine, cosine and tangent functions.
Wikimedia
Wikipedia: Trigonometric Function
This page from Wikipedia, a free and open-source encyclopedia, covers how to solve a variety of trigonometric equations, most of which involve substitution with a trigonometric identity. The identities themselves are not covered, but...
Varsity Tutors
Varsity Tutors: Hotmath: Practice Problems: Trigonometric Ratios
Sixteen problems cover a variety of topic of trigonometric ratios. 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 Solution" button to check each...
University of Vienna (Austria)
Trigonometry: Law of Sines
This is demonstration of how the law of sines works. It uses Java applets to manipulate the triangle and allows the user to explore what happens to the values of the triangle as the sides are changed.
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.
CK-12 Foundation
Ck 12: Trigonometry: Trigonometric Identities and Equations
[Free Registration/Login may be required to access all resource tools.] Describe general forms and graphs for cosine and sine equations.
Lawrence Hall of Science
The Math Page: An Approach to Calculus: Derivatives of Trig. Functions
Here is a site that clearly and thoroughly explains how to find the derivative of each of the six trigonometric functions. There are example problems solved, problems for the student to attempt, and answers to the student problems. Point...
Khan Academy
Khan Academy: Trigonometric Ratios in Right Triangles
Given the side lengths of a right triangle, find the sine, cosine, or tangent of one of the acute angles. Students receive immediate feedback and have the opportunity to try questions repeatedly, watch a video or receive hints.
University of St. Andrews (UK)
University of St. Andrews: Trigonometric Functions
This site from the University of Saint Andrews provides an historical look at the origins of trig functions. This site ties together mathematics and history from Hipparchus to Ptolemy to Lambert.
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.
Varsity Tutors
Varsity Tutors: Hotmath: Practice Problems: Graphs of Trigonometric Functions
Hotmath provides 20 practice problems on graphs of trigonometric functions. Each of the practice problems include a step-by-step guide for solving their graphs.
Curated OER
Zona Land: Overlapped Graph of the Six Trig Functions
An overview of the six trig functions and their graphs. The site is a little difficult to navigate but is good for finding a graph of a trig function.
Calculator Soup
Calculator Soup: Trigonometric Function Graphs F(x)
Images of trigonometric function graphs.
Government of Alberta
Learn Alberta: Math Interactives: Exploring Trig Ratios
Investigate the cosine, sine, and tangent ratios of trigonometry using this interactive Learn Alberta math resource. Students will use these ratios to determine a right triangle's unknown side or angle. Be sure to follow the link to the...
Vision Learning
Visionlearning: Wave Mathematics: Trigonometric Functions
Learn how to use trigonometric functions to study waves.
Varsity Tutors
Varsity Tutors: Hotmath: Algebra Review: Trigonometric Ratios
Find a quick, concise explanation of the trigonometric ratios: sine, cosine and tangent. Examples are given and clearly explained.