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Math Help - f(f(x))

  1. #1
    Junior Member
    Joined
    Mar 2010
    Posts
    41

    f(f(x))

    The question is:

    Let f(x) = 1/(1 + x). What is:

    (i) f(f(x))

    I think it's supposed to be f(f(x)) = 1/[1+(1/(1 + x))]

    But the answers say that it's (x + 1)/(x + 2)

    If I re-arrange the equation, the best I can get is (x + 1)/2, where does the extra x come from (if I'm even doing it right at all in the first place)?
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  2. #2
    Junior Member
    Joined
    Mar 2010
    Posts
    41
    Wait it's okay, I got it! I wasn't adding the 1 to the (1 + x) properly!
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