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Math Help - Inverse Equation

  1. #1
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    Inverse Equation

    What's the inverse of f(x)=e^(x-11)-8

    I got y= ln(x+8)+11

    Is this right?

    Thanks.
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  2. #2
    Junior Member allsmiles's Avatar
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    Hmmmmm... doing the math i got the same answer, so i supose it is right.


    great job


    if you want to show your work, i can dobble check to see if i did it the same way you did.
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  3. #3
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    e^(i*pi)'s Avatar
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    Quote Originally Posted by p4pri View Post
    What's the inverse of f(x)=e^(x-11)-8

    I got y= ln(x+8)+11

    Is this right?

    Thanks.
    I get the same answer too. Although technically it is written as f^{-1}(x) = \ln(x+8)+11

    Note that the domain of f^{-1}(x) is limited to x>-8 because we cannot take the log of a negative number or 0 (well we can but then we get complex answers). The range is all the real numbers.


    edit (more info): If you look at f(x) you may notice that the range is f(x) > -8 and that the domain is all the real numbers. If you compare that to the range and domain of f^{-1}(x) you will see they've 'swapped' around. This is a property of all inverse functions. Furthermore functions and their inverses are reflections in the line y=x
    Last edited by e^(i*pi); May 30th 2010 at 11:48 AM. Reason: see post
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