Education Technology

# Activities

• ##### Subject Area

• Math: Precalculus: Trigonometry (Triangle and Circular Functions)

9-12

45 Minutes

• ##### Device
• TI-Nspire™ CX/CX II
• TI-Nspire™ CX CAS/CX II CAS
• TI-Nspire™
• TI-Nspire™ CAS
• ##### Software

TI-Nspire™
TI-Nspire™ CAS

3.0

## Unit Circle

#### Activity Overview

Students will be able to describe the relationship between the unit circle and the sine and cosine functions. They will be also able to describe the shape of the sine and cosine curves after "unwrapping" the unit circle.

#### Objectives

• Students will be able to describe the relationship between the unit
circle and the sine and cosine functions.
• Students will be able to describe the shape of the sine and cosine
curves after "unwrapping" the unit circle.

#### Vocabulary

• continuous function
• periodic function
• unit circle

#### About the Lesson

• Students will use a slider to change the measure of the central
angle of a unit circle and make connections with right triangle
trigonometry.
• As the measure of the central angle changes, line segments
representing the length of a highlighted leg of the right triangle in
the unit circle appear on the screen. Students will discover
relationships between the right triangle and the line segments
creating the sine and cosine functions.
• Prerequisite knowledge: right triangle trigonometry and continuous
functions