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Solving infinite limit at infinity

  1. May 30, 2010 #1

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    Solving infinite limit at infinity[solved]

    Really need help here. I somehow missed a fundamental principle and I have an Analysis exam tomorrow

    I need to use this definition for [tex]lim_{n\rightarrow\infty}a_{n}=-\infty[/tex]:

    For all A<0 there exists [tex]K_{A}>0[/tex],
    [tex]x>K_{A}[/tex]
    such that f(x)<A. I perfectly understand this.

    Now i need to use it to show:
    [tex]lim_{n\rightarrow\infty}(3n-2n^{2})=-\infty[/tex]
    I can do it for a specific case using the definition, like for n>=2 its clear that f(x) will be less than 0, using the definition. But I am not sure that this is a general proof. I.e. that doesn't show that f(x) will tend to infinity.

    [ok I solved it and dont know how to delete the post so ya. shud have checked out "related threads" before posting sorry]
     
    Last edited by a moderator: May 31, 2010
  2. jcsd
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