Activities

Download
- Teacher Files
- Teacher Notes DOC
- Teacher Notes PDF
- Student Files
- Student Activity DOC
- Student Activity PDF
- VERITRIG.8xp
Alignment
- Standards Alignment
- Textbook Alignment
Subject Area
- Math: Precalculus: Trigonometry (Triangle and Circular Functions)
Author

Texas Instruments
Level

9-12
Activity Time

45 Minutes
Device
- TI-83 Plus Family
- TI-84 Plus
- TI-84 Plus Silver Edition
- TI-84 Plus C Silver Edition
- TI-84 Plus CE
Software

TI Connect™
TI Connect™ CE
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Trigonometric Identities

Published on 01/17/2011

Students will verify, prove, and explore trigonometric identities symbolically, numerically, and graphically.

Students will use the VERITRIG program to help prove the two trigonometric identities. They will use the Text tool to label a triangle drawn within the unit circle. Then students will write x and y in terms of cosθ and sinθ to prove the identity cos²θ + sin²θ = 1.
Students then prove the identity sec²θ = 1 + tan²θ using similar triangles and ratios.
After proving the identities, students can use the cosine and sine values of the angles in the unit circle to prove that the proof holds for each identity.