# trig

posted by
**charly**
.

using the fact that 5pi/8=1/2(5pi/8) and the half angle identity for cos to find the exact (in terms of radicals) value of cos(5pi/8)

posted by
**charly**
.

using the fact that 5pi/8=1/2(5pi/8) and the half angle identity for cos to find the exact (in terms of radicals) value of cos(5pi/8)