$\"\"$

The trigonometric function is $\"\"$ .

$\"\"$ .

Since the angle terminates in quadrant III, the cosine function is negative.

$\"\"$

The value of the trigonometric function : $\"\"$ .

$\"\"$

Multiply the numerator and denominator by $\"\"$ .

$\"\"$ .

Thus, $\"\"$ .

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The exact value of $\"\"$ .