The purpose of this task is to use the Pythagorean Theorem to establish a fundamental trigonometric identity for an acute angle. The reasoning behind this identity is then applied to calculate a cosine for a given obtuse angle. Aligns...

Learners explore trigonometric identities. Definitions of the Pythagorean, reciprocal, tangent, and negative identities are included.

The goal of this task is to study some values of sin x and cos x for different angles, and to look for and then explain patterns that are seen. Aligns with HSF-TF.C.8.

This lesson from S.O.S. Math provides great information on the polar form of a complex numbers. It has many formulas and examples, and it also discusses the polar coordinates as well. Links are provided for additional subjects.

[Free Registration/Login Required] Excellent diagrams, including the Ferris wheel, depict parametric equations and their related graphs.

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

This tutorial highlights the numerous trigonometric identites (but does not define the basic trigonometric functions).

Lists the basic trigonometric identities, and specifies the set of trig identities to keep track of, as being the most useful ones for calculus.