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Derivitive with ln - don't understand

  1. Mar 11, 2009 #1
    1. The problem statement, all variables and given/known data

    Differentiate the following:
    y = ln(2x^2 - 2) / x^2 - 1



    3. The attempt at a solution

    The answer is y' = -ln(2x^2 - 2)(2x)(x^2 - 1)^-2 + 4x / 2x^2 - 2 (x^2 - 1)^-1

    I understand all of it except 4x / 2x^2 - 2, how does ln(2x^2 - 2) derive into 4x / 2x^2 - 2?
     
  2. jcsd
  3. Mar 11, 2009 #2

    rock.freak667

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    [tex]\frac{d}{dx}(ln(f(x))=\frac{f'(x)}{f(x)}[/tex]
     
  4. Mar 11, 2009 #3
    Oh okay, thanks, never seen that one before.
     
  5. Mar 11, 2009 #4

    Hurkyl

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    If you look closely, you'll notice that's just the chain rule....
     
  6. Mar 11, 2009 #5
    Really? How?
     
  7. Mar 11, 2009 #6
    To see how it is the chain rule, think about what the derivative of ln x is.
     
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