10-1

This past week we took nine weeks exams, so we worked on our study guides for chapters 7, 8, and 9 all week. After our exam on Thursday we started chapter 10 on Friday. In section 10-1 we learned how to find the exact values of trig functions and how to simplify them. This section does not allow us to use our calculators. All you need to know for this section is the trig chart and two formulas.

Formulas:
cosine (alpha -/+ beta) = cosine alpha cosine beta -/+ sine alpha sine beta
sine (alpha +/- beta) = sine alpha cosine beta +/- cosine alpha sine beta

Alpha and Beta come straight out of the trig chart

Example:
Find the exact value of sine 150
1. Look on your trig chart and see if there are any two degrees that add up to 150. 90 and 60 add up to give you 150.
2. They want sine so plug into your sine formula. Sin( 90 + 60) = sin90 cos60 + cos90 sin60
3. Plug in from your trig chart. (1) (1/2) + (1) (square root 3/2)
4. Your final answer is 2