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Inverse function of this function?

This question is from the Edexcel IGCSE Mathematics June 2010 4H paper:

g(x) = x / (x-1)

Find the inverse function for this.

Can someone help me with this please because when I try it I end up with an answer the same as the question itself.

Thanks in advance!

3 Answers

Relevance
  • 10 years ago
    Favorite Answer

    Don't worry that the answer is the same as the question itself. It just so happens that you are quite right :)

    The inverse function of g(x) in your case is indeed g(x)!

    g(x)=y=x/(x-1) => y(x-1)=x => xy -y = x => xy-x = y => x(y-1)=y => x= y/(y-1)

    So inverse(g(x)) = g(y) :D

  • 10 years ago

    Set y = x/(x-1)

    y (x-1) = x

    yx - y - x = 0

    ( y - 1)x - y = 0

    x = y / (y - 1)

    Hence, the inverse is

    y= x/( x-1), which is the same as the original.

  • cidyah
    Lv 7
    10 years ago

    Let y = x/(x-1)

    Switch x and y

    x = y/(y-1)

    solve for y

    (y-1) x = y

    xy - x = y

    y(x-1) = x

    y = x/(x-1)

    f^-1(x) = x/(x-1)

    Note:

    g(x) and its inverse are the same.

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