$\"\"$

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The function is $\"\"$ and point is $\"\"$ .

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Rewrite the function.

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$\"\"$

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Apply derivative on each side with respect to $\"\"$ .

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$\"\"$

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Product rule of derivatives : $\"\"$ .

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$\"\"$ .

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Derivative of sine function : $\"\"$ .

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Derivative of cosine function : $\"\"$ .

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$\"\"$

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$\"\"$ .

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$\"\"$

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Find the value of the derivative function at $\"\"$ .

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$\"\"$

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$\"\"$ .

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$\"\"$

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Graph :

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Graph the function and the derivative function.

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$\"\"$

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Observe the graph.

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The value of the derivative function at the point $\"\"$ is $\"\"$ .

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$\"\"$

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Derivative function is $\"\"$ .

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The value of the derivative function at the point $\"\"$ is $\"\"$ .