Protect yourself from identity theft! Establishing a strong understanding of the Pythagorean identity allows learners to prove that sine^2x + cos^2x = 1. They then use the identity to find sine or cosine ratios given the other.

Concepts

trigonometric ratios, unit circle, trigonometric identities, pythagorean theorem, sine, cosine, quadrants

Show More Show Less

Additional Tags

math

Show More Show Less

Instructional Ideas

• Allow learners to review the Pythagorean Theorem using variables or expressions for side lengths
• Emphasize the effect of quadrants on the values of the sine and cosine ratios

Classroom Considerations

• Pupils should have a strong understanding of the unit circle and the trigonometric ratios
• The 16th in a 19-part series of trigonometry lessons

Pros

• Provides adaptation suggestions for ELL pupils
• Includes a set of practice problems for independent practice along with a worked-out solution guide

Cons

• None

Common Core

HSF-TF.C.8