1. Limited time only! Sign up for a free 30min personal tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

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

    n/a

    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

    HallsofIvy

    User Avatar
    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
     
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook