Lesson Plan

Prove that sin^2(theta) + cos^2(theta) = 1 using the unit circle equation x^2 + y^2 = 1

Explain why this identity holds for all values of theta, not just acute angles

Use the Pythagorean identity to find sin(theta) given cos(theta), or vice versa

Determine the correct sign of the missing value using the quadrant of the angle

Find tan(theta) given sin(theta) or cos(theta) and the quadrant

Derive the related identities tan^2(theta) + 1 = sec^2(theta) and 1 + cot^2(theta) = csc^2(theta) by dividing through

HSF.TF.C.8

HSF.TF.C.8: Prove the Pythagorean identity sin^2(theta) + cos^2(theta) = 1 and use it to find sin(theta), cos(theta), or tan(theta) given sin(theta), cos(theta), or tan(theta) and the quadrant of the angle.