Sum and Difference Formulas Skill 34

Objectives… Use sum and difference formulas to evaluate trigonometric functions, verify trigonometric identities, and solve trigonometric equations.

Example– Evaluating a Trigonometric Function Find the exact value of (a) cos 75 ° and (b) sin . Solution: a. cos 75 ° = cos(30 ° + 45 °) = cos 30  cos 45  – sin 30  sin 45 

Example–Solution b. sin (u – v)

Example– An Application of a Sum Formula Write as an algebraic expression

Example– Reduction Formula

Example– Reduction Formula

Example– An Application of a Sum Formula

Example– Solving Trigonometric Equations #84

Example– Solving Trigonometric Equations #84 Not in domain

Example– Verify the Trigonometric Equation

34 Sum & Difference Formulas Summarize Notes Videos Homework Worksheet Quiz