Results 1 to 8 of 8

Math Help - function

  1. #1
    Member
    Joined
    Apr 2010
    Posts
    135

    function

    f(x) = 5(2+x) and g(x) = x/5 +7 which maps R into R

    find f^{-1}x = x

    i know how to find find f^{-1}x but am not sure what to so after that.

     f^{-1}x =
    y = x\5 -2
    Follow Math Help Forum on Facebook and Google+

  2. #2
    MHF Contributor
    Joined
    Mar 2010
    From
    Florida
    Posts
    3,093
    Thanks
    5
    It looks like you are done. I don't see anything else you are supposed to do unless there is more to the question you didn't post. Do you need to find the inverse of g(x) too?
    Follow Math Help Forum on Facebook and Google+

  3. #3
    Member
    Joined
    Apr 2010
    Posts
    135
    Quote Originally Posted by dwsmith View Post
    It looks like you are done. I don't see anything else you are supposed to do unless there is more to the question you didn't post. Do you need to find the inverse of g(x) too?
    ok i will post the question in order..

    1. find f^{-1} x

    2.determine the value of x which f^{-1} x=x
    Follow Math Help Forum on Facebook and Google+

  4. #4
    MHF Contributor
    Joined
    Mar 2010
    From
    Florida
    Posts
    3,093
    Thanks
    5
    \displaystyle f^{-1}(f(x))=x
    Follow Math Help Forum on Facebook and Google+

  5. #5
    Member
    Joined
    Apr 2010
    Posts
    135
    Could you show me how that is done. Am afraId I may interpret it the wrong way. Thanks.
    Follow Math Help Forum on Facebook and Google+

  6. #6
    MHF Contributor
    Joined
    Mar 2010
    From
    Florida
    Posts
    3,093
    Thanks
    5
    \displaystyle f^{-1}(5(2+x))=\frac{5(2+x)}{5}-2=\cdots
    Follow Math Help Forum on Facebook and Google+

  7. #7
    Member
    Joined
    Apr 2010
    Posts
    135
    Ok thanks alot
    Follow Math Help Forum on Facebook and Google+

  8. #8
    MHF Contributor

    Joined
    Apr 2005
    Posts
    15,298
    Thanks
    1276
    Since you had already determined that [tex]f^{-1}(x)= \frac{x}{5}- 2, determining x such that f^{-1}(x)= x just means solving \frac{x}{5}- 2= x.
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. Replies: 20
    Last Post: November 27th 2012, 05:28 AM
  2. Replies: 0
    Last Post: October 19th 2011, 04:49 AM
  3. Replies: 4
    Last Post: October 27th 2010, 05:41 AM
  4. Replies: 3
    Last Post: September 14th 2010, 02:46 PM
  5. Replies: 2
    Last Post: September 2nd 2010, 10:28 AM

Search Tags


/mathhelpforum @mathhelpforum