Charlie's.

In Chapter 10 we learned formulas and how to solve by plugging into those formulas.
In this blog, though, i'm just going to do sections 10-1 and 10-2.

the Formulas for these two sections are:
sin(alpha +\- beta) = sin(alpha) cos(beta) +\- cos(alpha) sin(beta)
cos(alpha +\- beta) = cos(alpha) cos(beta) -\+ sin(alpha) sin(beta)
tan(alpha +\- beta) = tan(alpha) +\- tan(beta) / 1 -\+ tan(alpha) tan(beta)
cos(alpha +\- beta) = 1 -\+ cot(alpha) cot(beta) / cot(alpha) +\- cot(beta)

One thing is you'd get the answer of the second half of the formula and find the begining.

For example:
sin20 cos60 + cos20 sin60
to simplify you take the alpha and beta and the symbol inbetween the two multiplication things.
so... sin20 cos60 + cos20 sin60 = sin(20 + 60) = sin80

Another thing is you'd get the beginning of the formula and have to solve for the end.

For example:
cos(60-32)
to solve you just expand into the formula.
so... cos(60-32) = cos60 cos32 + sin60 sin32