Education Technology

Investigating the Sine and Cosine Functions

Published on 02/08/2007

Activity Overview

Students use Cabri? Jr. to draw a circle and investigate the relationship between the coordinates of a point on the circle and sine and cosine of the angle whose terminal side passes through that point. NY State Algebra 2 & Trigonometry Standards covered: PS.3, PS.4, RP.2, CN.1, CN.2, A.55, A.57, A.60, A.62, A.66, A.70

Before the Activity

Install the Cabri Jr. App on the students' graphing calculators using TI Connect?, a TI Connectivity Cable, and the Unit-to-Unit Link Cable. Review the concepts of reference angles, coterminal angles, and the quadrant names with students before beginning the activity as the angles found using Cabri Jr. will only be between 0 and 180. Students will have to determine the value of the angle based on the quadrant it falls in. See the attached PDF file for detailed instructions for this activity. Print the student worksheet from the attached PDF file for your class.

During the Activity

Distribute the student worksheets to your class.Follow the Activity procedures: Draw a circle. Draw and measure the radius of the circle. Draw an angle in quadrant one and measure the length of the angle. Measure the coordinates of the point where the terminal side of the angle meets the circle. Collect data according to the instructions provided and answer follow the up questions.

After the Activity

Review student results: As a class, discuss questions that appeared to be more challenging and student findings. Re-teach/Review concepts as necessary and assign ?What Have You Learned? questions.