Talk:Multiplicative inverse/Archive 1

Archive 1

reciprocal function

Could someone add an article on the reciprocal function? —Preceding unsigned comment added by 67.68.10.118 (talk • contribs) 00:27, 26 November 2006

I've created a redirect to this page.--agr 04:51, 26 November 2006 (UTC)

This page is a bit much as somewhere for someone to end up, if say they're a non-mathematician, and all they want to know what it means when an article says "actually, we're going to work with the reciprocal of this equation".

So I think a separate stub article for reciprocal (mathematics) would be useful. Jheald 21:54, 27 February 2007 (UTC).

Created Jheald 14:30, 3 March 2007 (UTC).

Inverse of zero?

The article says that zero does not have an inverse... WELL, lim x->0+ of 1/x = infinity and lim x->0- of 1/x = -infinity. So the inverse of 0 should be +/- infinity, should it not? —Preceding unsigned comment added by Ben Boldt (talk • contribs) 02:22, 17 May 2008 (UTC)

I changed the wording a little to fix this. Ben Boldt (talk) 02:33, 17 May 2008 (UTC)

i still don't understand please help me. —Preceding unsigned comment added by 68.84.5.115 (talk) 17:28, 4 November 2008 (UTC)

In the same way, you could say that the inverse of 3 is infinity. Michael Hardy (talk) 06:27, 23 December 2008 (UTC)

No, you couldn't show that the inverse of three is infinity in the same way, since the limit as x->3 of 1/x is 1/3, which would suggest the inverse of three is a third, as it is. His proof doesn't work because in order for it to be an inverse you need to show that 0 x infinity = 1. The limit as x goes to infinity of x.0 is 0, so that doesn't work. Oli — Preceding unsigned comment added by 87.194.173.194 (talk) 13:16, 4 January 2010 (UTC)

"Multiplicative Inverse" is if you take 1 divided by a number. For example, the multiplicative inverse of 2 is 1/2. You are wondering why the multiplicative inverse of zero is infinity.

Imagine taking the multiplicative inverse of smaller and smaller numbers.

8 -> 1/8.
4 -> 1/4.
2 -> 1/2.

Notice that as the number you start with gets smaller, the number that comes out is larger.

Continuing...

2 -> 1/2
1 -> 1
1/2 -> 2
1/4 -> 4
1/8 -> 8

1/1000 -> 1000
1/1 million -> 1 million

Look how small 1/1 million is. It's getting very close to zero, and the multiplicative inverse is a million, which is very large. If you keep going forever, until the input is so small that it IS zero, the output will be so large that it IS infinity.

So the multiplicative inverse of zero is infinity. Ben Boldt (talk) 18:55, 4 November 2008 (UTC)

In a sense, that's correct. But we don't have a definition of infinity to which it applies, so it would take longer to explain it than the concept is worth, IMHO. — Arthur Rubin (talk) 20:00, 4 November 2008 (UTC)

I attempted to get the idea across in the simplest, non-technical terms possible, and I think that's exactly what I did. I agree that the formal proof would not be worth the time especially on the talk page. In the main article it might be, though, if anyone is interested in that. Ben Boldt (talk) 20:05, 4 November 2008 (UTC)

In the same way, the multiplicative inverse of 3 is infinity. 06:28, 23 December 2008 (UTC)

The multiplicative inverse of 3 is 1/3. I think you may be talking about 3/0, which is infinity. Ben Boldt (talk) 04:26, 29 December 2008 (UTC)