1. Warm Up Evaluate each of the following.
1) cos (150 ○) 2) sin (360 ○) 3)
4) ) )
7) tan(240○) ) csc(-225○)
9) cot(20π/3) ) sec(- π/4)

2. Pass up your homework and clear your desk for the QUIZ

3. Homework Answers

4. Homework Answers

5. Sum, Difference, and Half Angle Identities

6. Use your calculator to approximate cos75°.
Make sure you’re in Degree Mode!
Does cos(30°+45°) = cos30° + cos45°?

7. Sum/Difference Identities (You need to MEMORIZE these)
cos(A + B) = cosA cosB - sinA sinB
cos(A - B) = cosA cosB + sinA sinB
Examples
Calculate:
1. Cos75° Sec75°

8. sin(A + B) = sinA cosB + cosA sinB sin(A - B) = sinA cosB - cosA sinB
Memorize these
sin(A + B) = sinA cosB + cosA sinB
sin(A - B) = sinA cosB - cosA sinB
Examples
Calculate:
Sin(7π/12)
Csc(7π/12)

9. Practice

10. Memorize these
Example: Calculate

11. More Examples

12. Half Angle Identities… (You do not have to memorize these)

13. Use the half angle identity to evaluate…
1. tan(π/8) 2. sin(105°)