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Differential equation with three variables

  1. Jul 14, 2012 #1
    Can anyone help me on this equation. I want to find a solution for dr/dt. a, b and c are constants.

    Last edited: Jul 14, 2012
  2. jcsd
  3. Jul 14, 2012 #2


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    Hey Nilupa and welcome to the forums.

    You need to show us what you have tried, any thoughts you have and any work of any kind you have done on the problem.

    Also this is a non-linear partial differential equation of which many don't have known analytic solutions, so this should be kept in mind.
  4. Jul 14, 2012 #3


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    In general, you can't solve a single equation for multiple unknowns. And here you have, even counting a, b, and c as given constants, two unknown functons, r and s, in one equation.

    (This is NOT a "partial differential equation"- there is only one independent variable, t.)
  5. Jul 14, 2012 #4


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    Yes I apologize, I mis-read the graphic wrong: it's not a PDE.
  6. Jul 15, 2012 #5
  7. Jul 15, 2012 #6
    Thank you so much... Now I think i can solve it.
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