1. 4.3: Circular Trigonometry February 4, 2013

2. Warm-up a)Find the remaining sides of the triangle if i.x = 5 ii.r = 1

3. Learning Targets

4. Standard Position Angles Vertex Initial Side Terminal Side Cartesian Plane / coordinate system / coordinate plane

5. Negative Angles

6. Coterminal Angles: Angles that have the same terminal side and the same initial side.

7. Coterminal Angles

8. How many coterminal angles are there to a given angle?

9. Example a)Find cos(30 ○ ) b)Find cos(150 ○ ) c)Find cos(210 ○ ) d)Find cos(300 ○ )

10. Reference Triangles A reference triangle is used to evaluate trig functions for non-acute angles. A reference triangle always has the x-axis as one side (never the y-axis). Which is the reference triangle? A B

11. When are the functions positive?

12. Re-Defining Sin, Cos, Tan If t is an angle on the unit circle, then:

13. The Unit Circle: A circle with radius = 1

14. Quadrantal Angle

15. Page 380

16. Example Find tan(300 ○ )

17. Example