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Double-Angle and Half-angle Formulas

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Presentation on theme: "Double-Angle and Half-angle Formulas"— Presentation transcript:

1 Double-Angle and Half-angle Formulas

2 Double-Angle Formulas

3 Finding exact values

4 Solutions

5 Solutions

6 solutions

7 Establishing Identities
Develop a formula for sin (3θ) in terms of sin θ and cos θ.

8 Other variations of double-angle formulas

9 Establishing an identity
Write an equivalent expression for cos^4θ that does not involve any powers of sine or cosine greater than 1.

10 Solution

11 Half angle formulas

12 Finding Exact Values Find the exact value of cos (15 degrees)
Find the exact value of sin (165 deg) Find the exact value of tan (195 deg)

13 Finding Exact Values Remember to be careful to check the sign of the cosine of the angle Remember to look at the quadrant to determine if the final answer is positive or negative

14 Finding Exact Values

15 Solutions

16 alternative formula

17 On-line help Tutorial Video Help

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