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Math Help - Composite Functions

  1. #1
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    Composite Functions

    If f(x) = x/(x - 1), find f(f)(x).
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  2. #2
    Grand Panjandrum
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    Quote Originally Posted by symmetry View Post
    If f(x) = x/(x - 1), find f(f)(x).
    1. I don't like your notation, f is defined as a function on real numbers,
    so what f(f)(x) means is debatable. I prefer the notation (f o f)(x) or f(f(x))
    for composite function.

    f(x)=x/(x-1),

    so:

    f(f(x))=f(x/(x-1)),

    let y=x/(x-1), then:

    f(f(x))=f(y)=y/(y-1)=[x/(x-1)]/[x/(x-1)-1]=[x/(x-1)]/[(x-(x-1))/(x-1)]=x

    RonL
    Last edited by CaptainBlack; January 20th 2007 at 02:25 PM.
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  3. #3
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    ok

    Your notation is the correct way but I cannot type as you did using this keyboard but at least you understood.

    Thanks!
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