1. 5.2 Sum and Difference Formulas
Objectives: Use the sum and difference formulas for sine, cosine and tangent.

2. DO NOW
A pendulum 4 feet long travels 10 feet in one direction each swing. What is the angle measure of the swing, as measured in radians?
2.5
In standard position, an angle of − 𝜋 3 radians has the same terminal angle as what degree measure?
300o

3. Sum and Difference Formulas for Cosines, Sine, and Tangent

4. Sum and Difference Formulas for Cosines, Sine, and Tangent
Use the angle sum identity to find the exact value of each.

5. Sum and Difference Formulas for Cosines, Sine, and Tangent
Use the angle sum identity to find the exact value of each.

6. Sum and Difference Formulas for Cosines, Sine, and Tangent
Use the angle sum identity to find the exact value of each.

7. Speed Quiz #6- February 27th
5.2 Sum and Difference Formulas
Objectives: Use the sum and difference formulas for sine, cosine and tangent.
Assignment: pg. 603 #’s 9, 11, odd, odd
Speed Quiz #6- February 27th

8. DO NOW In the figure below, if sin 𝑛 𝑜 + sin 𝑛 𝑜 =1 , then 𝑥 𝑜 =
A) 90 B) 60 C) 45 D) 30
In the figure below, sinB – sinA =
1/8 B) ½ C) 5/8 D) 2/3

9. Example: Verifying an Identity
Verify the identity:
cos ( 𝛼−𝛽) cos 𝛼 cos 𝛽 = cos 𝛼 cos 𝛽 + sin 𝛼 sin 𝛽 cos 𝛼 cos 𝛽
Divide by cos α cos β.
The identity is verified.

10. Example: Verifying an Identity
Verify the identity:
The identity is verified.

11. Example: Finding Exact Values
Suppose that for a quadrant II angle and
for a quadrant I angle Find the exact value of 𝛼

12. Example: Finding Exact Values
Suppose that for a quadrant II angle and
for a quadrant I angle Find the exact value of 𝛽 𝛽

13. Example: Finding Exact Values
Suppose that for a quadrant II angle and
for a quadrant I angle Find the exact value of

14. Verify the Identity

16. 61.

17. 61.

19. 57.

20. 59.

21. 63.