$\"\"$

\

The expression is $\"\"$ .

\

$\"\"$ (Apply Pythagorean identity)

\

$\"\"$ (Subtract $\"\"$ from each side) \ \

\

$\"\"$ (Simplify) \ \

\

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

\

$\"\"$ (Evaluate power: $\"\"$ ) \ \ $\"\"$

\

$\"\"$ (Subtract: $\"\"$ ) \ \

\

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

\

$\"\"$ (Simplify)

\

$\"\"$ (Apply reciprocal identity: $\"\"$ ) \ \

\

$\"\"$ (Simplify) \ \

\

$\"\"$ is in the third quadrant, csc $\"\"$ is positive,

\

Therefore $\"\"$ . $\"\"$

\

The value of $\"\"$ .