$\"\"$

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The integral is $\"\"$ .

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$\"\"$

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From double-angle identity : $\"\"$ .

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$\"\"$

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$\"\"$

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Double-angle identity : $\"\"$ .

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$\"\"$

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$\"\"$ .

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$\"\"$

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Consider $\"\"$ .

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

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

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

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Substitute corresponding values in integral.

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$\"\"$

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$\"\"$

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Substitute equation (2) in equation (1).

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$\"\"$ .

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$\"\"$

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$\"\"$ .