$\"\"$

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(a)

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$\"\"$ .

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Differentiate on each side.

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$\"\"$ .

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Consider right hand side of the expression.

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$\"\"$

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= Left hand side expression of (1).

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$\"\"$ .

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$\"\"$

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(b)

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(i)

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The region is bounded by $\"\"$ , $\"\"$ .

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Rotation is about $\"\"$ -axis.

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Find the points of intersection.

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Observe the graph: The point of intersections are $\"\"$ and $\"\"$ .

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It is symmetric about $\"\"$ axis.

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The volume of the solid is $\"\"$ .

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$\"\"$

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$\"\"$

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$\"\"$ cubic units.

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(ii)

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The region is bounded by $\"\"$ and $\"\"$ .

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Rotation is about $\"\"$ -axis.

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By using calculator: $\"\"$ .

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The volume of the solid is $\"\"$ .

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

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$\"\"$

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$\"\"$

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$\"\"$ cubic units.

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$\"\"$

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(a) $\"\"$ .

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(b)

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(i) $\"\"$ cubic units.

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(ii) $\"\"$ cubic units.