# What does lim=infinity mean?

1. Oct 21, 2007

### buckr02

I can't believe I'm asking this, because I should know this answer but I'm now doubting myself.

If a function goes to infinity as x approaches some real number, would we say the limit as x approaches that number is infinity or would we say that it does not exist?

Doesn't the limit always have to be a real number, but infinity isn't one?

So for example:
the limit as x approaches 0 from the right of 1/x is infinity or not defined?

2. Oct 21, 2007

### EnumaElish

It is a question of whether you are in the reals or the extended reals. The latter includes infinity.

3. Oct 21, 2007