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Math Help - Quick question on inverse functions

  1. #1
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    Quick question on inverse functions

    Hi, just starting to recall how to grab the inverse of a function from last year. I just encountered a question that didn't say if it wanted the answer in x= or y=. Is it safe to assume that if the question does not specify that the answer should be written in x= ?

    Simple example:

    A function f is defined by y=2x+1. What is the equation of the inverse of f?

    This question doesn't seem to specify whether to write it in x= or y= so I would assume the answer to be x=2y+1.

    Or does something in that question tell me to write it as 'x=' without my realizing it?

    Any help is appreciated, thanks.


    EDIT: Just occurred to me it might be helpful if I show what I mean by 'y=', I'll just put the above equation into 'y=' to hopefully make more sense of what I'm getting at with the 'x=' 'y=' bit.

    y=(x-1)/2


    (I think?)
    Last edited by cb220; September 2nd 2008 at 06:04 PM.
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  2. #2
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    you are correct ...

    if the original function is y = 2x+1, then the inverse is
    x = 2y+1 or y = (x-1)/2.

    the last two equations are equivalent ... the last y represents f^{-1}.
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  3. #3
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    I see, thank you
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