1. TRIG IDENTITIES

2. What is an identity?  Identity: a statement of equality that is TRUE as long as neither side is undefined. Except when x = -1

3. Basic Identities

4. Why?

5. Other identities based on P.T. identity:

6. Cofunctions A B

7. Cofunction Identities

8.  Sin(40) =Sin(-40)=  Cos(40)=Cos(-40)=

9. Even-Odd Identities

10. We will be doing 5 things with identities…  Evaluating – finding a value (numerical answer)  Simplifying – condensing (answer is usually a single trig function)  Factoring – un-doing the box/FOIL  Solving – getting “x” by itself (up to 4 possible solutions)  Verifying/Proving: showing that the left side and right side are equivalent.

11. Ex 1. Evaluate  Find the value of sine & cosine if

12. Ex 1. Find a trig function 

13. Ex 2. Simplify

14. Ex 3. Factor

15. Ex.4 Solve

16. You Try