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December 4th, 2011, 06:45 PM   #1
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Positive and negative results

Hello, I have a limit:

I've simplified it to such view:


Wolframalpha shows, that there are 2 results: ±inf:
http://www.wolframalpha.com/input/?i...%2C+x-%3E0+%29

I can't understand, why does the result have ±?
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December 4th, 2011, 06:55 PM   #2
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Re: Positive and negative results

Wolfram has showed these results as the limit of x->0 has a different result depending which side you approach the limit from.
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December 4th, 2011, 06:57 PM   #3
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Re: Positive and negative results

We are given:







We have then:



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December 4th, 2011, 06:57 PM   #4
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Re: Positive and negative results

So, can I just calculate it and leave the answer as: inf? Would it be right?
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December 4th, 2011, 07:03 PM   #5
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Re: Positive and negative results

I would simply state that the limit does not exist. There is a vertical asymptote of x = 0. On the left the function goes to negative infinity and on the right it goes to positive infinity, much like the function f(x) = 1/x.
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December 4th, 2011, 07:04 PM   #6
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Re: Positive and negative results

Okay, thanks for the tip The question is solved.
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