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The equation is $\"\"$ .

Rewrite the above equation.

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Apply integral on each side.

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

Use the property: $\"\"$ .

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Apply the integral of trigonometric function : $\"\"$ .

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Apply the integral of trigonometric function : $\"\"$ .

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The value is $\"\"$ .

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Substitute $\"\"$ in $\"\"$ .

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