precalc help !!!!!!!
posted by Haley on .
if someone could show me how to solve this problem
1) cos(345°)

did you notice that 345 = 36015 ?
cos(345)
= cos15
cos15 = cos(4530)
= cos45cos30 + sin45sin30
= (√2/2)(√3/2) + (√2/2)(1/2)
= ( √6 + √2)/4
cos 345 = (√6+√2)/4