$\"\"$

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The function $\"\"$ is decreasing function.

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The integral is $\"\"$ .

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In this case $\"\"$ .

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The number of subintervals are $\"\"$ .

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Width $\"\"$

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$\"\"$

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$\"\"$ .

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Since the function is decreasing, the right end points result in a lower sum and the left end points result in a upper sum.

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Lower sum is $\"\"$ .

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The right end points are $\"\"$ .

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$\"\"$

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Lower sum is $\"\"$ .

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$\"\"$

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Upper sum is $\"\"$ .

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The left end points are $\"\"$ .

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$\"\"$

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Upper sum is $\"\"$ .

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$\"\"$

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Lower sum is $\"\"$ .

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Upper sum is $\"\"$ .