$\"\"$

\

The expression is $\"\"$ .

\

Pythagorean identity : $\"\"$ .

\

$\"\"$

\

Apply reciprocal identity : $\"\"$ .

\

\

$\"\"$

\

Quotient identity : $\"\"$ .

\

$\"\"$ .

\

Therefore, $\"\"$ is equivalent to $\"\"$ .

\

$\"\"$

\

Option G is the correct choice.