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-   -   How do I show that f and g are inverse functions? (https://www.askmehelpdesk.com/showthread.php?t=375294)

  • Jul 13, 2009, 07:23 PM
    cowboys93
    How do i show that f and g are inverse functions?
    it says to show how f and g are inverse functions (a)algebraically(b)graphically
    f(x)=x-5, g(x) x=5
    Please helpppp I don't understand this.

    allso it says to find the inverse function of f informally. Verify that f(f-1(x))=x and
    f-1(f(x))=x
    1.f(x)=1/3x

    I tried this one and I don't know how to do it. I hate working with fractions.

    please & thank you verryy muuchhh.:o
  • Jul 14, 2009, 07:20 AM
    Unknown008

    You should know the relationship between a function and its inverse.

    To make the inverse of a function, for example f(x) = 10x - 2, you let it be y = 10x - 2 and make x the subject of the formula.







    Finally, replace x by which will represent the inverse of f(x) and replace y by x in your function;



    That's it for algebraically.

    For graphing, plot the two graphs. Inverse functions have some sort of 'mirror' line (or line of symmetry) along the line y=x. If they do have this property, then they are said to be the inverse of one another.

    For the first part;



    replace by the f inverse you just had, that is;



    Can you try for the remaining ones now?

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