$\"\"$

\

The trigonometric function is $\"\"$ .

\

Now we can find $\"\"$ .

\

Apply Pythagorean identity: $\"\"$ .

\

$\"\"$ (Substitute $\"\"$ ) $\"\"$

\

$\"\"$

\

$\"\"$

\

$\"\"$

\

$\"\"$ (Take square root of each side)

\

$\"\"$ $\"\"$

\

The value of $\"\"$ .