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Math Help - Inverse function problem

  1. #1
    the
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    Inverse function problem

    Let f(x) = 5 + x2 + tan(πx/2), where -1 < x < 1.

    Find f(f ^(-1)(7)).

    I'm not sure finding the inverse function of this is possible, but think I can find out what x has to equal to get -7, which is the first part. How do I move onto the second part?
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  2. #2
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    Quote Originally Posted by the View Post
    Let f(x) = 5 + x2 + tan(πx/2), where -1 < x < 1.

    Find f(f ^(-1)(7)).

    I'm not sure finding the inverse function of this is possible, but think I can find out what x has to equal to get -7, which is the first part. How do I move onto the second part?
    To me it looks like a trick question because

    1. f^{-1}(x) is the inverse function of f(x).

    2. f \left(f^{-1}(x)\right) = f^{-1}(f(x)) = x

    Can you take it from here?
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  3. #3
    the
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    Ah, yes! I fell for it, thanks!
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