1. Not finding help here? Sign up for a free 30min 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!

Subset math help

  1. Aug 21, 2010 #1
    1. The problem statement, all variables and given/known data

    F : R-{1/3} ---> R-{0}
    F(x) = 1/(3x-1)

    to show R-{0} [tex]\subseteq[/tex] image of F

    for any y in R-{0}, if we try to solve y=1/(3x-1), we find x=(1+y)/3y,

    F((1+y)/3y)=y

    2. Relevant equations

    R is real number

    3. The attempt at a solution

    so, if (1+y)/3y are the values for x in R-{0} such that F((1+y)/3y)=y

    but i don't understand, how is that showing R-{0} [tex]\subseteq[/tex] image of F

    explain to me please
     
  2. jcsd
  3. Aug 21, 2010 #2

    radou

    User Avatar
    Homework Helper

    Re: subset

    You have shown that if y is in R\{0}, then it is in the image of F, too, since for such a number y there exists a number x = (1 + y) / 3y whose image under F is y. (btw the image of F is defined as {F(x) : x is in R\{1/3}})
     
  4. Aug 21, 2010 #3
    Re: subset

    thanks, i get it now ^^
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook




Similar Discussions: Subset math help
  1. Subset math problem (Replies: 1)

  2. Discrete Math; Subsets (Replies: 3)

Loading...