$\"\"$

\

The trigonometric expression is $\"\"$ .

\

Apply trigonometric reciprocal identities: $\"\"$ and $\"\"$ .

\

$\"\"$

\

$\"\"$

\

$\"\"$

\

$\"\"$

\

Apply formula: $\"\"$ .

\

$\"\"$

\

$\"\"$ .

\

$\"\"$ .