1. Double-Angle Formulas
Section 5.5

2. Double-Angle Formulas

3. Solving a Multiple-Angle Equation
Solve

4. Using Double-Angle Formulas to Analyze Graphs
Analyze the graph of
in the interval [0, 2π]

5. Evaluating Functions Involving Double Angles
Use the following to find

6. Note
The double-angle formulas are not restricted to the angles 2Ө and Ө. Other double combinations, such as 4Ө and 2Ө or 6Ө and 3Ө, are also valid. Here are two examples.
By using the double-angle formulas together with the sum formulas you can form other multiple-angle formulas.

7. Homework
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