$\"\"$

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The function is $\"\"$ .

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Definition : The area A under a function $\"\"$ on $\"\"$ is

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$\"\"$

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where $\"\"$ and $\"\"$ .

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

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Width of the rectangle :

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$\"\"$

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$\"\"$

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$\"\"$

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$\"\"$

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Substitute $\"\"$ and $\"\"$ in the definition of area.

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$\"\"$

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The area under the graph of $\"\"$ is $\"\"$ .

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$\"\"$

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The area under the graph of $\"\"$ is $\"\"$ .