$\"\"$

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The function is $\"\"$ .

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$\"\"$

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The function of the parabola is $\"\"$ .

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Area enclosed by parabola in the $\"\"$ -axis ,and the lines are $\"\"$ and $\"\"$ .

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Substitute $\"\"$ in $\"\"$

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$\"\"$

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$\"\"$

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Substitute $\"\"$ in $\"\"$

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$\"\"$

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$\"\"$

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Substitute $\"\"$ in $\"\"$

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$\"\"$

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$\"\"$

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Therefore $\"\"$ .

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$\"\"$

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$\"\"$ .

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$\"\"$

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$\"\"$ .