1. The Unit Circle The unit circle is a circle of radius 1 centered at the origin of the xy-plane. Its equation is x 2 +y 2 = 1.

2. The Unit Circle

7. Terminal Points  A terminal point is the point where the terminal side of the angle intersects the unit circle.  Coordinates are (x, y) or :

8. The Unit Circle

10. Example: Find the terminal point for 7 π /6:

11. Example: Find the terminal point for 5 π /3:

12. The Unit Circle Given a distance, t, along the unit circle starting from (0, 1) and going counterclockwise (if t is positive) we arrive at a point, P(x, y), called the terminal point. 1 1 t P(x,y)P(x,y)