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Relative Extrema

  1. Mar 25, 2009 #1
    1. The problem statement, all variables and given/known data

    The cost of producing x units is given by:


    Find the minimum average cost. x >= 1

    2. Relevant equations


    Marginal cost is C'(x)

    3. The attempt at a solution

    This is what I have done so far:


    C'(x)= (110ln(x)-910)/x^2

    setting C'(x)=0

    I get x=e^(910/110)


    Plugging in my value for x I get an increasing number validating, or I thought my x=value. Webwork tells me that e^(910/110) is incorrect for the minimum cost.
  2. jcsd
  3. Mar 26, 2009 #2


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    Science Advisor

    This derivative is incorrect. Please show how you got it, step by step.

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