$\"\"$

\

The trigonometric identity is $\"fraction$ .

\

Consider $\"\"$ .

\

Apply pythagorean identity: $\"begin$ .

\

$\"\"$ \ \

\

$\"equal$ \ \

\

$\"equal$

\

$\"\"$

\

Apply quotient identity: $\"fraction$ .

\

$\"equal$

\

$\"fraction$ .

\

$\"\"$

\

$\"fraction$ .