$\"\"$

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The expression is $\"\"$ and $\"\"$ ;

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$\"\"$ .

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Use the reciprocal identity to find the value of $\"\"$ .

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$\"\"$

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$\"\"$

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$\"\"$

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From the pythagorean trigonometric identity $\"\"$ .

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$\"\"$ .

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$\"\"$

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Since $\"\"$ , $\"\"$ is to be considered.

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$\"\"$

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$\"\"$ .