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Thread: Proving functions Question

  1. September 25th 2009, 10:08 PM #1
    MATHDUDE2
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    Proving functions Question

    How do I show that f(f^-1(x))=x? Where do I start working from and what do I substitute?

    Thanks!
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  2. September 25th 2009, 11:46 PM #2
    red_dog
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    If f(x)=y then f^{-1}(y)=x.

    Then f(x)=f(f^{-1}(y))=y.
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