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Homework Help: Cone/Cost Max/Min Question

  1. Jun 1, 2007 #1
    1. The problem statement, all variables and given/known data

    http://img128.imageshack.us/img128/3923/12mx7.png [Broken]

    2. Relevant equations

    3. The attempt at a solution


    c'=0.06(pie)r - 0.06kr^-2
    r^3=k^1/3 / (pie^1/3)

    h/r= 1/1

    I'm not sure if what I did here is right. I didn't put all the steps up there.
    Last edited by a moderator: May 2, 2017
  2. jcsd
  3. Jun 1, 2007 #2

    yup you have the right answer r/h does = 1

    if you briefly want the steps just to check

    COST = 0.12*(pie)*r*h + 0.06*(pie)*r^2

    find derivative U get

    -(K * 0.12)/(r^2) + 0.12*(pie)*r

    equate this derivative to zero

    thus -K + (pie)*(r^3) = 0

    THUS (pie)*(r^3) = K

    but K = (p)*(r^2)*h

    thus r = h
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