The Unit Circle
Move the theta slider to investigate unit circle values.
1) Use the app above to find for each of these angles: 30, 45, 60, 90, 120, 135, 150, and 180 degrees. Sketch and label each angle on your unit circle handout.
2) Use the patterns on your unit circle to predict (cos 210, sin 210). Then use the app to verify your prediction and add it to your unit circle.
3) Predict and check cosine and sine of the following angles: 225, 240, 270, 300, 315, and 330 degrees. Add them to your unit circle.
4) As you change the angle from 0 to 360 degrees, when is cosine positive? Why?
5) As you change the angle from 0 to 360 degrees, when is sine positive? Why?