This trigonometry textbook takes the learner from a basic understanding of angles and triangles through the use of polar coordinates on the complex plane. Written by a mathematician-engineer, examples and problems here are used to...

Move on into trigonometry. An informative eBook takes the content of a College Algebra course and adds more relating to trigonometry and trigonometric functions. The content organization allows pupils to build upon their learning by...

Take a step beyond Algebra 2. Learners use the eBook to learn concepts from the typical Precalculus course. Content starts off with a short review of functions in general and moves on to the basic functions, finishing up with more...

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

Define the trigonometric ratios in terms of ratios of the sides of a right triangle.

This site provides an explanation on the limits of trigonometric functions. Topics included on the site are infinite limits, no limits at infinity and a fundamental limit.

This section introduces radians an alternative to degrees as a way to measure the rotation around a circle. It also begins to draw connections between radians and trigonometric identities.

Discover sine and cosine ratios in trigonometric ratios.