# Activities

• • • ##### Subject Area

• Math: Algebra I: Linear Functions
• Math: Geometry: Points, Lines and Angles

• ##### Author 9-12
College

60 Minutes

• ##### Device
• TI-89 / TI-89 Titanium
• TI-92 Plus / Voyage™ 200
• ##### Report an Issue

Exploring functions with CAS

#### Activity Overview

In this activity students use the CAS tool to explore sin, cos, and tan functions. They expand the functions and find the domain. They also prove the conjectures.

#### Before the Activity

• See the attached PDF file for detailed instructions for this activity
• Print pages 1 - 4 from the attached PDF file for the class
• #### During the Activity

Distribute the pages to the class.

• Consider a cos function and expand it
• Note the function is even if n is even and odd if n is odd
• Consider a sin function and expand it
• Note for all n the function is odd
• Consider a tan function and expand it
• If n is even , the denominator has degree n and the numerator has degree n - 1, and if n is odd, the numerator has degree n and the denominator has degree n - 1
• Prove the above statements using CAS
• Graph and find the zeros of the functions
• #### After the Activity

Review student results.

• As a class, discuss questions that appeared to be more challenging
• Re-teach concepts as necessary