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: HELP I do not understand!

  1. Mar 22, 2008 #1
    HELP!!! I do not understand!

    1. The problem statement, all variables and given/known data
    Define f(x)=2x, x is rational and x+3 when x is irrational. Find all points where g(x) is continuous and prove continuity at these points

    2. Relevant equations
    From analysis homework and using the real definition of continuity

    3. The attempt at a solution

    Graphing g(x) I can see that the only point that will be continuous will be at x=3, how would you show using the definition that this point is continuous. Also is this the only point. I have been struggling, please help a girl in distress. lol
  2. jcsd
  3. Mar 22, 2008 #2


    User Avatar
    Science Advisor
    Homework Helper

    … 'tis I … tiny-tim! …

    :smile: … don't worry that pretty little head … :smile:

    Just choose an epsilon, and find a delta such that f(3 + x) - 6 < epsilon, for all x < delta, and all your worries will go away! :smile:
  4. Mar 22, 2008 #3
    so I just solve it like a limit problem? Thank you so much, I just knew someone would help a girl in distress lol.
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook