Posted by Johnathan on Thursday, May 1, 2008 at 4:18pm.
Use the half angle formula to find
cos(pi/12)

trig  Reiny, Thursday, May 1, 2008 at 4:22pm
Hint #1 : pi/12 = 1/2 of pi/6, and you should be familiar with the trig ratios of pi/6 or 30º
Hint #2 : cos 2A = 2cos^2 A  1