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: 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


    User Avatar
    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? :-)
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook