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Math Help - Relations and functions: Inverses

  1. #1
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    Relations and functions: Inverses

    I have no idea how to do these. her is a example

    If
    ,
    then f(2) =
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  2. #2
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    Quote Originally Posted by pletchera View Post
    I have no idea how to do these. her is a example

    If
    ,
    then f(2) =
    Hi pletchera,

    f(x)=3x+1

    f(2)=3(2)+1

    f(2)=7

    We don't need the inverse function to find f(2).
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  3. #3
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    Quote Originally Posted by masters View Post
    Hi pletchera,

    f(x)=3x+1

    f(2)=3(2)+1

    f(2)=7

    We don't need the inverse function to find f(2).
    Makes so much sense now thank you!

    but would it be the same for this one?

    f (x) = 3x + 1 and f-1 = x-1/3
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  4. #4
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    Quote Originally Posted by pletchera View Post
    Makes so much sense now thank you!

    but would it be the same for this one?

    f (x) = 3x + 1 and f-1 = x-1/3
    I'm not sure what you're asking but f(x) is a function of x. f^{-1}(x) is the inverse function of x.

    If you want to find f(x), simply substitute whatever x is into your function.

    f(x)=3x+1

    f(2)=3(2)+1

    f(2)=7

    If you want to find out what f^{-1}(2) is, then

    f^{-1}(x)=\frac{x-1}{3}

    f^{-1}(2)=\frac{2-1}{3}

    f^{-1}(2)=\frac{1}{3}
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  5. #5
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    Also f(f^{-1}(x)) = x by definition
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