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Calculus - derivatives

  1. Oct 5, 2010 #1
    1. The problem statement, all variables and given/known data

    the total surface area of a right circular cylinder is given by the formula: (A = 2Pir(r + h) ).
    where r is the radius and h is the height.
    sub part a) find the rate of change of A with respect to h is r remains constant

    i know how to take derivatives. the only thing is that in this case, I am not sure how to take the derivative of h since it is only present in one term.

    2. Relevant equations
    the derivative equation

    3. The attempt at a solution
    i first ditributed the 2pir, to yield
    2pir^2 + 2pirh
    2pir^2(h/h) + 2pirh
    h (2pir^2 h^-1 + 2pi r)
    now i am stuck here. i cant take the derivative of all the h's in my problem, because one h is still present in the equation.
    **below is my attempt to still work with it.
    dA/dh = 1 times [-1(2pir^2h^-2) + 2pir
    final answer: (-2pir^2h^-2) + 2pir
    please can someone guide me on the technique i should use for getting the area to be in terms of h. any and all replies are welcome and appreciated
    1. The problem statement, all variables and given/known data

    2. Relevant equations

    3. The attempt at a solution
  2. jcsd
  3. Oct 5, 2010 #2


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    Don't ever double post again, ok?
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