Chapter 10-Section 2

This week we only learned one new lesson. This was a good thing because it would have been tough to grasp new meterial and study for exams. We started 10-1 this Friday. In this chapter we are not allowed to use calculators. The purpose of this section is to find exact values and to simplify. IF YOUR GOING TO SURVIVE THIS SECTION YOU HAVE TO KNOW YOU TRIG CHART! THERE IS NO WAY AROUND IT!

There are only two formulas to remember:
Cos(alpha +/- beta) = cosalpha cosbeta -/+ sinalpha sinbeta

Sin(alpha +/- beta) = sinalpha cosbeta +/- cosalpha sinbeta

Alpha and Beta come straight out of the trig chart.


Ex:Find the exact value of sin 105 degrees.

1. There are two degrees from the trig chart that add up to equal 105, so those are the two numbers you will use. 60 and 45
Alpha = 60 Beta = 45

2. Since it says find exact value of sin , you will use the sin formula.

Sin(60 + 45) = sin60 cos45 + cos60 sin453

You fill in everything on the right of the equal sign with the trig chart.
(square root 3/2)(square root 2/2) + (1/2)(square root 2/2)4. Square root 6/4 + square root 2/45

The Final answer is square root 6 + square root 2/4