Lesson Plan

Explain why cosine is an even function (cos(-x) = cos(x)) using reflection across the x-axis on the unit circle

Explain why sine is an odd function (sin(-x) = -sin(x)) using reflection across the x-axis on the unit circle

Classify tangent as an odd function and justify using tan = sin/cos

Demonstrate that sin and cos have period 2pi by showing that angles differing by 2pi have the same terminal point

Demonstrate that tangent has period pi and explain why geometrically

Use symmetry and periodicity properties to simplify trigonometric expressions

HSF.TF.A.4

HSF.TF.A.4: (+) Use the unit circle to explain symmetry (odd and even) and periodicity of trigonometric functions.