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!

Another question thrown at you

  1. Sep 21, 2006 #1
    I think I'll get banned soon posting multiple questions at the same time, but allow me to continue,
    if f,g:R-->R both of class C2(differentiable twice)
    Define F(x,y)=f(x+g(y))
    Show that (DxF)(DxDyF)=(DyF)(D^2xF) where D^2xF is second order partial derivative with respect to x
    I'm dying here...
  2. jcsd
  3. Sep 21, 2006 #2
    umm... forget it I think I can do this one.. lol
  4. Sep 21, 2006 #3
    Umm... I'm stuck..
  5. Sep 21, 2006 #4
    Rewrite [itex]F_x(x,y)[/itex] and [itex]F_{yx}(x,y)[/itex] in terms of derivatives of [itex]f(x+g(y))[/itex] and [itex]g(y)[/itex] (the rest is straightforward manipulation, using the chain rule).
  6. Sep 21, 2006 #5
    Yes!!! It did work!! Thank you!
    Now please the remaining questions I posted, could anyone please answer??
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?

Similar Discussions: Another question thrown at you
  1. Another question (Replies: 3)

  2. Another question (Replies: 3)