PROOF 128
Prove.
The period of the trigonometric functions comes from one full turn
On the unit circle.
Definition D1
The circle of radius 1 centered at the origin is called the unit circle. Let P(θ) be the point where the ray making angle θ counterclockwise from the positive x-axis meets the unit circle, and for P(θ) = (x, y) define cos θ = x, sin θ = y.
Proof.
Related labs