Trigonometric functions describe the relationship between angles and sides in triangles. This chapter focuses on the three most common trigonometric functions, sine, cosine, and tangent. Here they are used in right triangles and later on in the unit cirle, introducing a new angle unit called the radian.

Subchapters:

• Using Right Triangle Trigonometry
• Building the Unit Circle
• Graphing Sine and Cosine Functions
• Using Trigonometric Identities