MATH110 April 2012
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Question 05 (e)
(e) Determine where ƒ is increasing and where it is decreasing.
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Whether f is increasing or decreasing is related to the sign of its first derivative, f' .
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We first find the derivative of f(x). Using the quotient rule,
Since the denominator is always positive on the domain (squaring always yields a positive number), we only need check whether the numerator is positive or negative. When , is positive and when , is negative. Thus f is increasing on the interval and decreasing on the interval .
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