1. Sum and Difference Formulas
Section 5.4
Sum and Difference Formulas

2. Objective By following instructions students will be able to:
Use sum and difference formulas to evaluate trigonometric functions.
Use the sum and difference formulas to verify identities and solve trigonometric equations.

3. Sum and Difference Formulas

4. Example 1: Evaluating a Trigonometric Function
Find the exact value of

5. Example 2: Evaluating Trigonometric Functions
Find the exact value of

6. Example 3: Evaluating a Trigonometric Expression
Find the exact value of given that , where and , where

7. Example 4: An Application of a Sum Formula
Evaluate

8. Example 5: Proving a Cofunction Identity
Prove the cofunction identity

9. Example 6: Deriving Reduction Formulas
Simplify each expression. a) b)

10. Example 7: An Application from Calculus
Verify that where .

11. Example 8: Solving a Trigonometric Equation
Find all solutions of in the interval .

12. Revisit Objective Did we…
Use sum and difference formulas to evaluate trigonometric functions?
Use the sum and difference formulas to verify identities and solve trigonometric equations?

13. Homework
Pg 408 #1-27 ODD, ODD