1. Solving Right Triangles and the Unit Circle
30 November 2010

2. Inverse Trigonometric Functions
We can “undo” trig functions by using the correct inverse trig function
Gives us the angle measurement (theda)
Represented with a small –1 in the upper right hand corner
Ex.
2nd button → correct trig function

3. Inverse Trigonometric Functions, cont.

4. Your Turn: Solve for theda

5. Solving Right Triangles
If given two sides of a triangle, then we can solve for any of the angles of the triangle. 4 5

6. Solving Right Triangles, cont.
Ask yourself what types of sides do you have: opposite, adjacent, and/or hypotenuse?
Pick the appropriate trig function to solve for
Solve for using the inverse trigonometric function 4 5

7. Solving Right Triangles, cont.4 5

8. Your Turn:
Pg. 430: 25 – 28

9. The Unit Circle – Introduction
Circle with radius of 1
1 Revolution = 360°
2 Revolutions = 720°
Positive angles move counterclockwise around the circle
Negative angles move clockwise around the circle

10. Coterminal Angles co – terminal
Coterminal Angles – Angles that end at the same spot
with or joint
ending

11. Coterminal Angles, cont.
Each positive angle has a negative coterminal angle
Each negative angle has a positive coterminal angle
Coterminal angles are equivalent
Example: 90° = –270°

12. Coterminal Examples
30°
390°
750°
–330°

13. On a separate sheet of paper, find three coterminal angles with the given angle measure. One of the angles must be negative.
1. 45° ° 3. –20°
° 5. –200°

14. Radian Measure Another way of measuring angles
Convenient because major measurements of a circle (circumference, area, etc.) are involve pi
Radians result in easier numbers to use