Step 1:
\(a) \ \
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The function is . \ \
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Apply derivative on each side with respect to x .
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Product rule of derivatives :
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Derivative of the logarithmic function: .
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Apply the power rule: .
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To find the critical numbers of , equate
to zero.
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The critical points are .
Step 2: \ \
\(b) The critical points are and the test intervals are
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Since logarithm function domain contains only positive values. \ \
\Interval | \Test Value | \Sign of ![]() | \
Conclusion | \
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Decreasing | \
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Increasing | \
Thus, The function is increasing on the interval and \ \
The function is decreasing on the interval .
Step 3: \ \
\(c) Consider . \ \
Apply derivative on each side with respect to x .
\Find : \ \
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If and
, then
has local minimum at
.
By the above definition has local minimum at
. \ \
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Step 4: \ \
\(d) .
Determination of concavity and inflection points :
\Equate to zero.
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Thus, the inflection points are split the intervals into
and
.
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Interval \ | \
Test Value | \Sign of ![]() | \
Concavity | \
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Down | \
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Up | \
Thus, the graph is concave up in the interval and
The graph is concave down in the interval .
Step 5: \ \
\(e) Inflection point at : \ \
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Inflection point is .
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Minimum point is .
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Maximum point is .