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!

Homework Help: Composition of functions (in set)

  1. May 13, 2009 #1
    1. The problem statement, all variables and given/known data

    A = {0, 1, 2, 3} f and g are fucntions mapping A to A where
    f = {(0,1),(1,2),(2,0),(3,3)} and g = {(0,2),(1,3),(2,0),(3,1)}

    (f o g)(1)

    2. Relevant equations

    3. The attempt at a solution

    The answer is 3 but i can not get it..
    the (1) on the right side means find the y value whem x = 1
    I think my (f o g) thing is not correct but i dont know how to do this..
    book just gave me an example but that is totally different from this one.
  2. jcsd
  3. May 13, 2009 #2


    User Avatar
    Homework Helper

    You know that [itex](f \circ g)(x)=f(g(x))[/itex]?. Can you tell us what value g(1) has?
    Last edited: May 13, 2009
  4. May 13, 2009 #3
    g(1) would be 3 as g has point (1,3)
  5. May 13, 2009 #4
    Ohh i got it.
    g(1) is 3 and as f has point (3,3) the answer is 3
  6. May 13, 2009 #5


    User Avatar
    Homework Helper

    Yep that is correct. Now what is the value of f(3)?

    Edit: Seems you beat me to it! Yes that's all correct.
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook