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Homework Help: Simple Differential problem

  1. Aug 8, 2007 #1
    Given that [tex] \frac{dx}{dy} = (\frac{dy}{dx})^{-1}\\ [/tex], differentiate throughout with respect to x and show that [tex] \frac{d^2x}{dy^2} = \frac{- \frac{d^2y}{dx^2}}{(\frac{dy}{dx})^3}\\[/tex].

    An attempt: [tex] \frac{d^2 x}{dx dy} = \frac{d (\frac{dy}{dx})^{-1}}{dx} \\ [/tex].

    I need help to get me started. Thanks for the help.
    Last edited: Aug 8, 2007
  2. jcsd
  3. Aug 8, 2007 #2
    Sorry for the second post. It wasn't meant to happen.
  4. Aug 8, 2007 #3
    It is better to start with [tex]\frac{d^2x}{dy^2} = \frac{d}{dy}\big(\frac {dx}{dy})[/tex]
    Last edited: Aug 8, 2007
  5. Aug 8, 2007 #4
    I answered your question in your other post.
  6. Aug 8, 2007 #5


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    Homework Helper

    That's the second time you done this today (at least). The idea of the Homework Forum is NOT to post complete solutions. The idea is to HELP the poster to solve the problem themselves by giving them guidance. Not to do the work for them. With alll due respect, you've been around for a while, hasn't anyone pointed this out to you before?
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