1. ## Simple Trig Simplifying

I don't know why, but I forget how to do the basics of some trig expressions because it's been so long.

How would I go about simplifying this:

cos(35°)cos(70°) - sin(35°)sin(70°)

I forget how to find the values of those numbers. I don't think I have to use the calculator though, do I?

2. $\displaystyle \cos(a+b) = \cos{a}\cos{b} - \sin{a}\sin{b}$