\"\"

\

The function is \"\".

\

The sub intervals are \"\".

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The function is decreasing on interval \"\".

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Observe the graph: The area is bounded between \"\" and \"\".

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Width \"\".

\

The minimum value on each sub interval occurs at the left end point.

\

The left end point is \"\".

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The sum of areas of the inscribed rectangles is called lower sum.

\

The lower sum is \"\".

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\"\"

\

\"\"

\

\"\"

\

\"\"

\

\"\" square units.

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\"\"

\

The maximum value on each sub interval occurs at the right end point.

\

The right end point is \"\".

\

The sum of areas of the circumscribed rectangles is called upper sum.

\

\"\".

\

\"\"

\

\"\"

\

\"\"

\

\"\"

\

\"\" square units.

\

\"\"

\

\"\" square units.

\

\"\" square units.