Step 1 :

The trigonometric function $\"\"$ .

Double-angle formulas : $\"\"$ ,

$\"\"$ , and

$\"\"$ .

Solve $\"\"$ by using Pythagorean identity.

Pythagorean identity: $\"\"$ .

$\"\"$

$\"\"$ . (Since the $\"image\"$ function is positive in fourth quadrant)

The trigonometric function $\"\"$ .

$\"\"$

The exact values of $\"\"$ , and $\"\"$ .