Concept:
The graphs of the sine and cosine functions can be constructed from the unit circle. Two such constructions are presented.
Sine, Cosine, and the Unit Circle
INSTRUCTIONS
Rotate the point at (1, 0) by dragging it counter-clockwise around the perimeter of the circle. The top circle will demonstrate how the sine function is constructed; the bottom circle will show how the cosine function is constructed.
EXPLORATIONS
Exploration 1: Why is it that the graph of the sine function starts at y = 0 and increases, while the graph of the cosine function starts at y = 1 and decreases?
Exploration 2: Why is the line with equation y = x needed to construct the graph of the cosine function?
