$\"\"$

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The integral is $\"\"$ .

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Apply integration by parts : $\"\"$ .

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Let $\"\"$ then $\"\"$ .

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Let $\"\"$ then $\"\"$ .

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$\"\"$

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Consider $\"\"$ .

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$\"\"$

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Therefore $\"\"$ .

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$\"\"$

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$\"\"$

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$\"\"$

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Consider $\"\"$ .

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$\"\"$

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$\"\"$

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$\"\"$ .

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$\"\"$

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Trigonometric property : $\"\"$ .

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Trigonometric property : $\"\"$ .

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$\"\"$ .

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$\"\"$ .

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$\"\"$

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$\"\"$

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