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Thread: Don't understand this differential equation

  1. January 22nd 2009, 02:28 AM #1
    lord12
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    Don't understand this differential equation

    How is (dx/dt)/(x(t) equivalent to (d/dt)ln|x(t)| ?
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  2. January 22nd 2009, 03:22 AM #2
    marek
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    why not.

    Deriving {ln[x(t)]}' you have 1/x(t) as external derivative (of logarithm) times internal derivative [x(t)]' (so dx/dt).
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