$\"\"$

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$\"\"$

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$\"\"$

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$\"\"$

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$\"\"$

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Let, $\"\"$ .

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Apply derivative to each side with respect to $\"\"$ .

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$\"\"$

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$\"\"$

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$\"\"$

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$\"\"$

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$\"\"$

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$\"\"$

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$\"\"$

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$\"\"$ $\"\"$

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$\"\"$ .

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