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: Expand f(x,y) = y^2/x^2

  1. Feb 11, 2006 #1
    How do u expand f(x,y) = y^2/x^2 about the point (1,-1) ? up to and including quadratic term???
  2. jcsd
  3. Feb 11, 2006 #2


    User Avatar
    Science Advisor
    Homework Helper

    Have you ever used the taylor series on multi-variable functions before?
  4. Feb 11, 2006 #3
    Not really, how? Have only done one variable so far.
  5. Feb 11, 2006 #4


    User Avatar
    Science Advisor

    The general term in a Taylor's series for f(x,y) about the point (a,b) is
    [tex]\frac{1}{(m+n)!}\frac{\partial^m f}{\partial x^m}\frac{\partial^n f}{\partial y^n}(x- a)^m(y- b)^n[/tex]

    (edited. Thanks, daveb)
    Last edited by a moderator: Feb 12, 2006
  6. Feb 11, 2006 #5
    Shouldn't that (x - b)^n be (y - b)^n?
  7. Feb 11, 2006 #6


    User Avatar
    Staff Emeritus
    Science Advisor
    Gold Member

    Bah, everybody likes to do it the hard way. :frown: f(x, y) is just a product of two things whose Taylor series you already know!
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook