1. Not finding help here? Sign up for a free 30min 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!

Partial derivatives/ total derivative

  1. Dec 21, 2006 #1
    1. The problem statement, all variables and given/known data
    I've attactched an image of the question, I hope this is ok, if not let me know and I'll copy it out onto a post,

    3. The attempt at a solution
    I've done parts (a) and (b) using the total derivative of f ( http://mathworld.wolfram.com/TotalDerivative.html ) but I can't get started on the last part. I've tried differentiating the expressions found in (a) but it doesn't seem to lead anywhere.

    A push in the right direction would be appreciated.
    Thanks
     

    Attached Files:

  2. jcsd
  3. Dec 21, 2006 #2

    HallsofIvy

    User Avatar
    Staff Emeritus
    Science Advisor

    You have the definitions. All I can say is "just do it"! You are asked to show that
    [tex]\frac{\partial f}{\partial x}= u\frac{\partial F}{\partial u}+ v\frac{\partial F}{\partial v}[/tex]
    u= excos(y), v= exsin(y) and F(u,v)= f(x,y).

    You will need to use the chain rule:
    [tex]\frac{\partial f}{\partial x}= \frac{\partial F}{\partial u}\frac{\partial u}{\partial x}+ \frac{\partial F}{\partial v}\frac{\partial v}{\partial x}[/tex]
     
  4. Dec 21, 2006 #3
    Thanks for the reply: I've done parts (a) and (b) already, it's the third part I'm struggling with (I can't quite see how your post relates to this bit). I won't post my solutions for these bits unless thay would be helpful, since they are show that... questions.
     
    Last edited: Dec 21, 2006
  5. Dec 21, 2006 #4
    Just to clarify since my use of 'last part' wasn't particularly precise, it's part (c) I'm struggling with.
    Thank you
     
  6. Dec 22, 2006 #5
    Solved it.
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?
Similar Discussions: Partial derivatives/ total derivative
  1. Total Derivative (Replies: 2)

  2. Total derivative? (Replies: 6)

  3. Total derivative (Replies: 1)

Loading...