Results 1 to 4 of 4

Math Help - Compositions

  1. #1
    Newbie
    Joined
    Mar 2011
    Posts
    5

    Compositions

    Prove that if g and f are 1-1, then so is g o f. And prove that if g and f are onto, then so is g o f.
    Follow Math Help Forum on Facebook and Google+

  2. #2
    MHF Contributor

    Joined
    Aug 2006
    Posts
    18,605
    Thanks
    1574
    Awards
    1
    Quote Originally Posted by andirc5192 View Post
    Prove that if g and f are 1-1, then so is g o f. And prove that if g and f are onto, then so is g o f.
    Please either post some of your own work on these problems or explain what you do not understand about the question.
    Follow Math Help Forum on Facebook and Google+

  3. #3
    Newbie
    Joined
    Mar 2011
    Posts
    5
    Oh geez yeah sorry about that. I understand that, by definition, g: A-->B is one to one if and only if w,x are in A where w is not equal to x and g(w)=g(x) implies that w=x, and the same thing for f:C-->D where y,z are in C. However i'm not sure how to connect the two through a composition.
    Follow Math Help Forum on Facebook and Google+

  4. #4
    MHF Contributor

    Joined
    Aug 2006
    Posts
    18,605
    Thanks
    1574
    Awards
    1
    If f:A\to B and g:B\to C what does g\circ f(x) mean?

    If g\circ f(y)= g\circ f(x) show y=x
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. Number of compositions
    Posted in the Discrete Math Forum
    Replies: 1
    Last Post: August 23rd 2011, 10:00 AM
  2. Forming the Compositions f(g(h(x)))
    Posted in the Algebra Forum
    Replies: 2
    Last Post: October 15th 2009, 04:42 PM
  3. compositions with sq roots
    Posted in the Pre-Calculus Forum
    Replies: 3
    Last Post: September 2nd 2008, 07:29 PM
  4. Compositions of functions
    Posted in the Pre-Calculus Forum
    Replies: 2
    Last Post: March 13th 2008, 04:48 AM
  5. f(x) and g(x) compositions
    Posted in the Pre-Calculus Forum
    Replies: 3
    Last Post: December 8th 2006, 04:32 AM

Search Tags


/mathhelpforum @mathhelpforum