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Solving a logarithm

  1. Apr 2, 2008 #1
    Can't remember how to do this (trying to solve for D):

    x = b/D + a*log(D)

    Any takers? Or is this impossible?
  2. jcsd
  3. Apr 2, 2008 #2


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    Additive inverse of b/D;
    Multiplicative inverse of 'a';

    Not sure if the rest is impossible. I'm stuck, since D is the input of the logarithm function and it occurs as a factor too. Am I forgetting something simple, or is this beyond "intermediate" level algebra?
  4. Apr 2, 2008 #3

    Maybe I can simplify the problem here:

    a, b, and c are real numbers, D is greater than zero

    c = b/D + a*log(D)

    how does one solve for D?
  5. Apr 2, 2008 #4


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    One doesn't. Not in terms of elementary functions anyway. It might be possible to solve it in terms of the "Lambert W function".
  6. Apr 2, 2008 #5
    How bout a Taylor Series expansion?
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