$\"\"$

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(a).

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The parabola is $\"\"$ .

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Consider the points $\"\"$ and $\"\"$ .

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The line equation is $\"\"$ .

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$\"\"$

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The linee quation is $\"\"$ .

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The area under $\"\"$ and $\"\"$ is:

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$\"\"$

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$\"\"$

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$\"\"$

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$\"\"$

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The area is $\"\"$ .

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$\"\"$

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(b).

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The function is $\"\"$ .

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

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$\"\"$

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The product rule of derivative : $\"\"$ .

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$\"\"$

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$\"\"$

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$\"\"$

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$\"\"$

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$\"\"$

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$\"\"$

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$\"\"$

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$\"\"$

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$\"\"$

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$\"\"$

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$\"\"$

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$\"\"$ .