$\"\"$

\

The expression is $\"\"$ .

\

Consider $\"\"$ .

\

Apply quotient identity : $\"\"$ .

\

$\"\"$

\

Apply pythagorean identity : $\"\"$ .

\

$\"\"$

\

Apply reciprocal identity : $\"\"$ .

\

$\"\"$ .

\

$\"\"$

\

$\"\"$ .