Step 1 :

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

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Consider $\"\"$ .

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Rewrite the differential equation as $\"\"$ .

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Separate t and h terms.

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$\"\"$

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Apply integrating on each side.

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$\"\"$

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$\"\"$

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

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$\"\"$ .

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The solution is $\"\"$ .