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(a)

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The curve is $\"\"$ , $\"\"$ .

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Definition for the area $\"\"$ :

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The area $\"\"$ of the region $\"\"$ that lies under the graph of the continuous function $\"\"$ is the limit of the sum of the areas of approximating rectangles is

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$\"\"$ .

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Width of the interval $\"\"$ and $\"\"$ .

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Here $\"\"$ and $\"\"$ .

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$\"\"$

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$\"\"$

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(b)

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Sum of cubes of first $\"\"$ integers is $\"\"$ .

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$\"\"$

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If $\"\"$ , then $\"\"$

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$\"\"$ .

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(a) $\"\"$ .

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(b) $\"\"$ .