10-1

This week was exam week. We did handouts on chapter 7-9 to get us ready for our exam. Friday we learned about section 10-1. In 10-1 you are not allowed to use a calculator if u do you will get a zero! We learned sine and cosine formulas.
Cos formula= Cos(alpha +/- beta)=(cosalpha)(cosbeta)-/+(sinalpha)(sinbeta)
Sin formula= sin (alpha +/- beta)=(sinalpha)(cosbeta)+/-(cosalpha)(sinbeta)

Alpha and beta comes from the trig chart and add or subtract to get the angle you are looking for.

Example:
Find the exact value of sin 15degrees
Alpha=45 degrees
Beta= 30 degrees

Sin (45degrees-30degrees) = (sin 45degrees) (cos 30degrees)-(cos45degrees) (sin 30 degrees)
(Square root of 2 over 2)(Square root of 3 over 2) – (Square root of 2 over 2) (1/2)

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

Your answer is Sin 15degrees= square root of 6-square root of 2 over 4.
Because it isn’t on trig chart u leave it at that if it was then you can simplify it.

This section is easy and not hard if you know your trig chart and everything you shouldn’t have any problems at all.