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Shrinking core model

  1. May 3, 2012 #1
    I have this solution that I don't quite understand


    from here I would have thought to separate the variables and integrate but the solution says

    ro/2* d(D)/d(t) = -kr Cao

    I guess my question is how are you able to do that? If you take the derivative of D, why is d(D)/d(t) still left behind?
  2. jcsd
  3. May 3, 2012 #2


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    hi cycling4life! :smile:

    (try using the X2 button just above the Reply box :wink:)
    chain rule … d(D3)/dt = 3D2 dD/dt :wink:
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