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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


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    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


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    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


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    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!
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