PreCalculus: Lesson Plan * 9/27/2006

Quickstart: Review for Chapter 4 ReTest

Chapter 4 ReTest
Lesson
(5.5) Multiple-Angle and Product-Sum Formulas [continued]
III. Half-Angle Formulas [continued]

IV Product-Sum Formulas
A. Product-to-sum formulas


B. Sum-to-product Formulas



2x = π/2, 3π/2, 5π/2, 7π/2 2x is double x so the interval is doubled [0, 4π)
x = π/4, 3π/4, 5π/4, 7π/4

cosx = 0
x = π/2, 3π/2

5.4 Quiz
1. Find all solutions on the inverval [0, 2π):
= 1
2. Use the sum and difference formulas to write the expression as the sine, cosine, or tangent of an angle.
sin110°cos80° + cos110°sin80°

3. Find the exact value of sin 225°. (Use the fact that 225° = 210° + 45°.)