Limit of 1/x = infinty?

limit

asked 11 years ago

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.

add a comment

1 Answer

Sort by » oldest newest most voted

answered 11 years ago

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

link

Comments

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 ( 11 years ago )

add a comment

Your Answer

Please start posting anonymously - your entry will be published after you log in or create a new account.

Add Answer

Question Tools

1 follower

Stats

Asked: 11 years ago

Seen: 2,346 times

Last updated: Feb 12 '14

Limit of 1/x = infinty? savecancel