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Intervals for limitsconti

  1. Dec 3, 2008 #1
    i would like someone to clear my doubts by explaining how it actually works..limits is one of the chapter i fear about it cause im quite blur with it..so i do need someone help me;v this que..given f(x)=1/x^3 what r the intervals for function continuous ?how to solve it?thanks :)
     
  2. jcsd
  3. Dec 3, 2008 #2

    lurflurf

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    f is continuous when
    lim_{h->0} [f(x+h)-f(x)]=0
    also composition of continuous funtions are continuous
    x^3 is everywhere continuous
    where is 1/x continuous?
     
  4. Dec 3, 2008 #3
    u meant composite of continuous function could also be a continuous for x^3???bt the limit is not given?!so what will be the interval for the function?how to differentiate between them and i still don't really get your point;i'm so sorry!!!
     
  5. Dec 3, 2008 #4

    lurflurf

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    let g(x)=x^3
    write f(x)=1/x^3
    as
    f(g(x))=g(1/x)=(1/x)^3
    g(x) is continuous for all real numbers (show this)
    so f is continuous at a if and only if 1/x is continuous at a.
    Where is 1/x continous?

    Start by giving the domain of 1/x
    A function cannot be continuous where it is undefined.
     
  6. Dec 3, 2008 #5
    hmm,then i think i get your point..anyway thanks alot...:smile:
     
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