How do you find the exact values of cos 22.5 degrees using the half-an

1.	How do you find the exact values of cos 22.5 degrees using the half-angle formula?
Answer» The exact valueof cos 22.5 degreesis 0.92387953... The half-angle formula for cos is cos x/2 = ± √ (1 + cosx) / 2.

Discussion