Wolfram Research
Wolfram Math World: Trigonometric Functions
This site provides a listing of the trigonometric functions and their inverses. Their notation is also addressed along with links to each of the fundamental trigonometric functions.
Other
Mecca: Review for Trigonometric Functions
A page of review problems on trigonometric functions. Answers are supplied.
Other
Personal Site: Sine and Cosine Do "The Wave"
This personal site provides a great animation of how the sine and cosine waves are formed. It connects the unit circle with the sine and cosine graph.
Interactive Mathematics
Interactive Mathematics: The Right Triangle and Applications
Learn how to "solve" a right triangle and apply the concept to real world situations using angles of elevation and depression.
Interactive Mathematics
Interactive Mathematics: Sine, Cosine, Tan & Reciprocals
The definitions of the six trig ratios are presented here, along with several examples of how to determine the ratios given 2 or more sides of a right triangle.
Interactive Mathematics
Interactive Mathematics: Applying Trigonometric Derivatives
The applications presented here demonstrate how the derivatives of trigonometric functions are used in real world problems.
CK-12 Foundation
Ck 12: Inverse of Functions Through Algebraic Manipulation
[Free Registration/Login may be required to access all resource tools.] Here you'll learn how to find the inverse of functions through algebraic manipulation.