# Talk:Infinity

This article refers to infinity as both being a number, and not being a number. Clarify. RDre 14:12, 11 April 2007 (EDT)

Can you fix it? --Ed Poor 14:13, 11 April 2007 (EDT)
I'm not qualified to judge which it is, but it's been dealt with now. RDre 14:19, 11 April 2007 (EDT)
Good start, but ...
• In the early 1600's Galileo began to show signs of a modern attitude toward the infinite, when he proposed that "infinity should obey a different arithmetic than finite numbers." But it was not until the late 19th century that Georg Cantor (1845-1918), a German mathematician, finally put infinity on a firm logical foundation and described a way to do arithmetic with infinite quantities useful to mathematics. [1]
We better start over. --Ed Poor 14:50, 11 April 2007 (EDT)
It wasn't that bad. Infinity is not a number, but it is greater than any real number. Tsumetai 14:52, 11 April 2007 (EDT)

XD yea. I had my fun. Pie5 21:04, 4 December 2007 (EST)

## Limit at the top of the page

Wow...Just wow...You guys claim that $\lim_{x \rightarrow 0} \frac{1}{x}$ is infinite.
...I don't know what to say to this. Any student who's had more than a week of calculus knows that this is incorrect. The correct statement is the limit from the right. The way you have it, the limit is undefined. Andy Schlafly, weren't you supposedly trained in a semi-technical field..? I'm amazed about the mistakes you make. Both here and on your "counterexamples to relativity" page....Wow... AndyFrankinson 20:02, 14 October 2011 (EDT)

## Rough and sloppy

I need a lot of help with this article. It had a mention of division by zero, which all mathematicians (and most math students) know is a forbidden operation. Don't put nonsense like that in math articles. --Ed Poor Talk 10:47, 18 September 2009 (EDT)

I like your new edits. What else are you thinking of adding? I will help where I can. --MarkGall 11:35, 18 September 2009 (EDT)

## My recent changes

I hope I have beaten the readers over the head sufficiently with the dictum that infinity is not a number, and hence dealt with Ed's complaint about this. You just don't divide by zero. Period. It's illegal. If you see an equation that appears to be dividing by zero, that equation is wrong.

I have taken out the stuff about "sample size". That refers to the size of a set in the field of statistics. We already cover set cardinality in general.

I have taken out the reference to "elementary techniques". That was meaningless, and seemed to be invoking the notion of "elementary proof", which is a page that needs a lot of work. Invoking that notion from here is just confusing the issue. Unless, of course, someone can clarify what that means, and give citations.

I can't figure out how to get spacing between the "math" parts and the "plain" parts in my list of 5 equations, so it looks horrible. Does anyone know how to do this? I know how in LaTeX, but that's way too complicated for a wiki, and probably wouldn't work.

PatrickD 15:35, 19 September 2009 (EDT)