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Derivative Chain Rule Question

  1. Aug 18, 2011 #1

    Say x=position, v=velocity, a=acceleration, t=time.



    EDIT: I just realized that 2/x is not a constant and thus I shouldn't have treated it as a constant (taking the derivative of it as 0). However, I don't understand how to take the derivative with respect to t of it.
  2. jcsd
  3. Aug 18, 2011 #2


    Staff: Mentor

    Use the chain rule.
    d/dt(2/x) = d/dx(2/x) * dx/dt

    If you work through this, you'll get what you show as the correct answer.
  4. Aug 18, 2011 #3
    By definition the time derivative of position is velocity.
  5. Aug 18, 2011 #4
    Ugh, I forgot how to use the chain rule *slaps forehead*. I get it now. It was hard to visualize 2/x as a "function within a function".

    Thanks guys!
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