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Math Help - How to find the inverse of f(x)=x+sqrt(x)?

  1. #1
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    How to find the inverse of f(x)=x+sqrt(x)?

    f(x)=x+\sqrt{x}

    Is it even possible to find the inverse of this?

    *edit* the question is find f^{-1} (6) but to do that I must 1st find f^{-1} (x)
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  2. #2
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    it is possible, but rather pointless for this exercise, you just say x=y+\sqrt{y}
    Last edited by artvandalay11; October 30th 2009 at 12:23 PM. Reason: it is possible
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  3. #3
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    Quote Originally Posted by artvandalay11 View Post
    when you say is it possible i believe you're talking about elementary operations and as far as i know, you can't solve for that inverse algebraically in terms of y, you just say x=y+\sqrt{y}
    *edit* the question is find f^{-1} (6) but to do that I must 1st find f^{-1} (x)
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  4. #4
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    no, you just need to find what value of x gives 6 as an answer,

    when they say find f^{-1}(6) they are asking what value of x gives 6 as an output for f(x), and you do not need a formula for f^{-1}

    Just by looking I can see the answer is 4

    6=x+\sqrt{x}
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  5. #5
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    Yes, x= 4 works. And that is as good a method as any!
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