$\"\"$

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The differential equation is $\"\"$ , $\"\"$ .

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$\"\"$

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$\"\"$ .

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Apply integral on each side.

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$\"\"$ .

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$\"\"$ .

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Apply integration power rule: $\"\"$ .

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Apply trigonometric integration rule: $\"\"$ .

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$\"\"$

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$\"\"$ .

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The equation is $\"\"$ .

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$\"\"$

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Find constant value.

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The condition $\"\"$ .

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Substitute $\"\"$ and $\"\"$ in equation.

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$\"\"$

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Substitute $\"image\"$ in equation $\"image\"$ .

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The equation is $\"image\"$ .

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$\"\"$ .

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The condition $\"\"$ , then $\"\"$ .

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$\"\"$ .

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$\"\"$ .

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The solution of differential equation is $\"\"$ .

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$\"\"$

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$\"\"$ .