Limit of 1/x = infinty?

limit

asked 2014-02-12 11:04:50 +0100

Anonymous

Hi,

I don't get why limit(1/x, x = 0) returns infinity.

Shouldn't it be undefined?

Interestingly, Mathematica also returns infinity, but on Wolfram Alpha it says two-sided limit does not exist.

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answered 2014-02-12 11:32:28 +0100

moroplogo

56 ●1 ●2 ●12 http://www.oviaivo.net/

Infinity is not signed There also +Infinity and -Infinity .

example :

sage: limit(1/x, x=0)
Infinity
sage: limit(1/x, x=0, dir='+')
+Infinity
sage: limit(1/x, x=0, dir='-')
-Infinity

Look at here : http://www.sagemath.org/doc/reference/calculus/sage/calculus/calculus.html

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Thanks. I get it now, although returning infinity when asking for the two-sided limit seems a bit misleading to me. But it's not just sage doing it...

Cassio ( 2014-02-12 12:07:25 +0100 )edit

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Asked: 2014-02-12 11:04:50 +0100

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Last updated: Feb 12 '14

Limit of 1/x = infinty? edit