The integral is .

Consider .

In this case .

Width .

Substitute and .

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Calculate the at the interval boundaries.

 Trapezoidal rule :

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Substitute to values.

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The integral is .

Apply formula: .

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The actual vaulue of integral is .

Graph the function .

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Observe the graph:

The number of parts above the -axis and below the -axis are equal and cancelled.

Therefore, the actual value is .

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The actual vaulue of integral is .

The number of parts above the -axis and below the -axis are equal and cancelled.