$\"\"$

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The definite integral is $\"\"$ .

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Rewrite the integral as $\"\"$ .

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Apply Double angle formula: $\"\"$ .

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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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$\"\"$

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$\"\"$ .

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$\"\"$

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$\"\"$ .