$\"\"$

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The trigonometric identity is $\"\"$ .

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Consider left hand side identity : $\"\"$ .

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Tangent and cotangent functions $\"\"$ .

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$\"\"$

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$\"\"$

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$\"\"$

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$\"\"$

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$\"\"$

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= Righty hand side identity.

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$\"\"$

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$\"\"$ . \ \