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: Simple Question about Partial Derivatives

  1. Dec 6, 2005 #1

    JasonRox

    User Avatar
    Homework Helper
    Gold Member

    I'm working on this question, and I have no idea where they are getting this.

    They said to differentiate f(xt,yt) with respect to t where.

    Note: [itex]f_x[/itex] denotes partial derivative with respect to x.

    The answer is coming up as, from the book...

    [tex]f_t * x * t^{(n-1)} + f_t * y * t^{(n-1)}[/tex]

    Note: If it helps, f is a function such that f(xt,yt) = t^n * f(x,y).
     
    Last edited: Dec 6, 2005
  2. jcsd
  3. Dec 6, 2005 #2
    Try looking in your calculus book for 'chain rule for functions of several variables' or some similar topic.

    It's just a differentiation formula.
     
  4. Dec 6, 2005 #3

    JasonRox

    User Avatar
    Homework Helper
    Gold Member

    Yeah, that's exactly what I looked at.

    Where does t^(n-1) come from?

    Note: f(xt,yt)=t^n f(x,y)
     
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook