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Homework Help: Limits at infinity

  1. Feb 26, 2008 #1
    lim as x goes closer to minus infinity.

    x^4 + x^5

    now visibly the answer is minus infinity since the equation are simple. But aside from saying x^5 is bigger then x^4 could there be anything else to do ?
  2. jcsd
  3. Feb 26, 2008 #2
    why would the answer be minus infinity???
  4. Feb 26, 2008 #3
    well as the expression is written right now
    you cannot tell what the limit is since you will end up with infinity-infinity, which is an intermediate form, or how do u call it in english! But hopefully there is sth we can do to avoid this, here:

    x^4+x^5=x^4(x+1) so now infinity*(-infinity)=-infinity
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