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Homework Help: Derivative school work help

  1. Jul 22, 2010 #1
    1. The problem statement, all variables and given/known data

    let x=et and define y(x(t))=Y(t)

    Show that x(d/dx)y=(d/dt)Y

    2. Relevant equations


    3. The attempt at a solution

    i try using chain rule but

    x(dy/dt)(dt/dx) and i dont know how to make it to be dY/dt, and i don't have clue what is the point of x=et.. help T_T
  2. jcsd
  3. Jul 22, 2010 #2


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    Science Advisor

    Re: derivative

    Look at it the other way around. If [itex]x= e^t[/itex] then [itex]dy/dt= (dy/dx)(dx/dt)= e^t(dy/dx)= x(dy/dx)[/itex]. The point of "[itex]x= e^t[/itex] is that the derivative of [itex]x= e^t[/itex] is [itex]x= e^t[/itex].
  4. Jul 22, 2010 #3
    Re: derivative

    my goodness, thank you very very very much
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