Chapter 10 Section 1

Just as everybody else has been saying, we haven't really learned much this week, we just reviewed and tested and Chilled with FE FE. But one of the things that I ACTUALLY learned, was Section 10-1. Even though this sections does not permit the use of calculators, it still is very simple and easy to understand.

The formulas in 10-1 are as followed:

cos (alpha +/- beta) = cos alpha cos beta+/- sin alpha sin beta

sin (alpha +/- beta) = sin alpha sin beta +/- cos alpha cos beta

Now lets get to work!

Find the exact value of sin 15*
Alpha = 45 *
Beta = 30 *

Sin (45 * - 30 *) = (sin 45*) (cos 30*) - (cos 45*) (sin 30 *)
(Square root of 2 \ 2)(Square root of 3 \ 2) – (Square root of 2 \ 2) (1 \ 2)

Square root of 6 \ 4 – square root of 2 \ 4= square root of 6 - square root of 2 \ 4.

= Sin 15* = square root of 6-square root of 2 \ 4.

Now how easy was DAT! hehe

Also, here a little tip. Make sure you keep a keen eye for trig chart functions, if you miss one, then you may not be allowed to answer your problem correctly.

Happy Halloween