$\"\"$

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The integral is $\"\"$ .

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Substitute $\"\"$ .

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

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$\"\"$

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$\"\"$

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$\"\"$ .

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Substitute $\"\"$ and $\"\"$ .

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$\"\"$

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$\"\"$

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$\"\"$

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$\"\"$

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$\"\"$

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As $\"\"$ then $\"\"$ .

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$\"\"$

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From the figure $\"\"$ .

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$\"\"$

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$\"\"$

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$\"\"$

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$\"\"$ $\"\"$ .

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$\"\"$

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$\"\"$ $\"\"$ .