$\"\"$

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The function is $\"\"$

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$\"\"$ (Apply derivative with respect to t)

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$\"fraction$ (Apply the difference rule)

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$\"fraction$ (The multiply constant rule)

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$\"fraction$ (The power rule: $\"fraction$ )

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$\"\"$

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Given that $\"x$

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So, $\"fraction$ (Substitute $\"x$ )

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$\"fraction$ (Simplify)

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$\"fraction$ (Simplify)

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$\"\"$

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Therefore $\"\"$ .