5.2. The Sinusoidal Function Family http://www.ck12.org
Example B
Use your knowledge of the angles 0,π 2 ,π,^32 π, 2 πon the unit circle to get a complete cycle of the cosine graph.
Solution: The cosine function is thex-coordinates of the unit circle and measures width. By referring to a unit
circle or your memory, you can fill out a much shorter table than before.
TABLE5.5:
Angle (radians) Width (units)(^0) π 1
2 0
π 3 π -1
2 0
2 π 1
First plot these five points and then connect them with a smooth curve. This will produce the cosine graph.
Determining these five main points is the key to graphing sine or cosine graphs even when the graph is shifted or
stretched.