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Partial Derivative Question

  1. Jul 29, 2011 #1
    For the equation:


    using quotient rule:


    hy = (x+y+z)(1)-(y)(1) / (x+y+z)2
    = x+z / (x+y+z)2

    I am getting the correct answer when evaluating at a point, but is this differentiation correct?

    More specifically, when using the quotient rule for partial derivatives, is it correct to differentiate f and g with respect to y, and then apply the quotient rule? Is this method generally correct?
  2. jcsd
  3. Jul 29, 2011 #2


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    You are doing just fine. Yes, it is generally correct.
  4. Jul 30, 2011 #3


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    The partial derivative is just the ordinary derivative with the other variables treated like constants. All ordinary derivative laws apply to partial derivatives.
  5. Jul 30, 2011 #4
    Great, thanks for your help.
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