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Homework Help: Continuous functions

  1. Jan 28, 2012 #1
    1. The problem statement, all variables and given/known data
    Let f and g be two continuous functions defined on R.
    I'm looking to prove the fact that if they agree on Q, then f and g are identical.


    2. Relevant equations



    3. The attempt at a solution
    I'm not really sure where to start with this. Can someone point me in the right direction?
     
  2. jcsd
  3. Jan 28, 2012 #2
    What definition of continuity would you like to use??
    What characterizations of contintuity do you know??

    What's special about [itex]\mathbb{Q}[/itex]??
     
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