$\"\"$

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The expression is $\"\"$ .

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Consider $\"\"$ .

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Apply reciprocal identity : $\"\"$ .

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$\"\"$

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Apply quotient identity : $\"\"$ .

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$\"\"$

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Apply Pythagorean identity : $\"\"$ .

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$\"\"$

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Thus, $\"\"$ . $\"\"$

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$\"\"$ .