$\"\"$

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The trigonometric identity is $\"\"$ .

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Consider $\"\"$ .

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Quotient identity: $\"\"$ .

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$\"\"$

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Trignometric identity: $\"\"$ . \ \

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$\"\"$

\

\

Quotient identity: $\"\"$ .

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$\"\"$

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$\"\"$ .

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$\"\"$

\

$\"\"$ .