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Homework Help: Is 0*infinity an uncertainty

  1. Jan 19, 2009 #1
    in a calculus problem i am doing, i need to find the Limit of

    Lim (1+x)ln(e-1/x^2)-x

    i have brought it to a point where i have ln(e+1/x^2)+x(ln(e+1/x^2)-1)
    therefore my limit is 1-(0*inf)

    can i leave this as 1-0=1 and that would be my answer or do i somehow need to change it around to get 0/0 of inf/inf??
  2. jcsd
  3. Jan 19, 2009 #2


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    Gold Member

    I am not sure how did you arrive on your second sentence, but from there, you need to use L'hopital Rule on (ln(e+1/x^2)-1)/(1/x), though if you change variables you get that this is definition of the derivative of the function ln(e+u) at the point u=0, have I ruined it for you, have I? :-)
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