1. Last time…
Homework questions?

2. TRIG IDENTITIES
Section 5.8

3. 3 Identities to Memorize:
sin2Ө + cos2Ө = tan2Ө = sec2Ө 1 + cos2Ө = csc2Ө

4. tan2Ө means (tanӨ)2 Example If tanӨ=20˚, then tan2Ө = (20˚)2
***NOTE
tan2Ө means (tanӨ)2 Example If tanӨ=20˚, then tan2Ө = (20˚)2

5. Example 1
If tanӨ = 4/9, find secӨ Which identity would you use? The one that mentions tan and sec!!

6. Example 1
If tanӨ = 4/9, find secӨ 1 + tan2Ө = sec2Ө 1 + (4/9)2 = sec2Ө = sec2Ө = sec2Ө 81 secӨ = √97 9

7. Example 2
If sinӨ = 6/10, find cosӨ Which identity would you use? The one that mentions sin and cos!!

8. Example 2
If sinӨ = 6/10, find cosӨ sin2Ө + tan2Ө = 1 (6/10)2 + cos2Ө = 1 cos2Ө = cos2Ө = cosӨ = 8 or

9. Example 3
Reduce the following identity to a single term: csc2Ө - cot2Ө - sin2Ө = (1 + cot2Ө) - cot2Ө -sin2Ө = 1 - sin2Ө = cos2Ө

10. Example 4
Reduce the following to a single term: cosx ∙ cscx = cosx ∙ 1 sinx = cosx = cotx

11. HOMEWORK
Workbook p #3, 4, 8