1. Limited time only! Sign up for a free 30min personal tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Explicit Expression

  1. Jun 30, 2008 #1
    For the function f given by the equation f(x)=[tex]\frac{-2x}{3x-4}[/tex], determine where the relation f^-1 is a function. If f^-1 is a function, write an explicit expression for f^-1(x).

    Need help writing explicit expression. Any guidance?
  2. jcsd
  3. Jun 30, 2008 #2
    You have to check if the given function is invertible or not.If it is one-one and onto then it is invertible and f^-1 is a function or it exists.
    I don't get you , when you say 'explicit function'.You mean the inverse?
  4. Jun 30, 2008 #3


    User Avatar
    Science Advisor

    You first say "determine where the relation f-1 is a function" which implies that f-1 is a function for some values of x, not others. But then you say "If f-1 is a function". Are you sure it wasn't "determine whether the relation f-1 is a function?

    Let [itex]y= \frac{-2x}{3x-4}[/itex] and "swap" x and y:
    [tex]x= \frac{-2y}{3y-4}[/itex]
    Now can you solve that for y? If so, f-1 exists and you have found it.
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook