$\"\"$

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The yield function of stand of timber is $\"\"$ .

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(a)

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Limiting volume of the wood as $\"\"$ approaches to infinity.

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$\"\"$

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As $\"\"$ then $\"\"$ .

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$\"\"$

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Limiting volume of the wood as $\"\"$ approaches to infinity is $\"\"$ .

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$\"\"$

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(b)

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The rate of change in yield is the first derivative of function.

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$\"\"$

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Apply derivative on each side with respect to $\"\"$ .

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$\"\"$

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$\"\"$

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$\"\"$

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Substitute $\"\"$ .

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$\"\"$

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The rate of change in yield when $\"\"$ is $\"\"$ .

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Substitute $\"\"$ .

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$\"\"$

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The rate of change in yield when $\"\"$ is $\"\"$ .

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$\"\"$

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(a) Limiting volume of the wood as $\"\"$ approaches to infinity is $\"\"$ .

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(b) The rate of change in yield when $\"\"$ is $\"\"$ .

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The rate of change in yield when $\"\"$ is $\"\"$ .