Question

Find the exact value of cos 7π/12 using half-angle identities.

Answer 1

it is half of \(\frac{7\pi}{6}\)

Answer 2

use
\[\cos(\frac{7\pi}{12})=\pm\sqrt{\frac{1+\cos(\frac{7\pi}{6})}{2}}\]

Answer 3

although since you are in quadrant 2, it is negative, not positive

Answer 4

so -(sqrt) 2-(sqrt(3))/2

Answer 5

so do i have the right answer