# L'ptsle's rule (spelt wrong)

1. Dec 1, 2007

### theoritician

It works for 0/0 or infinity/infinity

Does it work for -infinity/infinity? wiki suggests no.

Books give examples for lim xln(x) and does it and appplies this rule. HOwever it's really -infinity/infinity!

2. Dec 1, 2007

### Gib Z

Of course it works for -infinity/infinity! Thats because (if and only if the limit exists) $$\lim_{x\to a} - f(x) = - \lim_{x\to a} f(x)$$. The second part is one of the cases you know it works.

3. Dec 1, 2007

### cristo

Staff Emeritus
Are you talking about l'Hopital, or l'Hospital's rule? If so, that is a weird spelling in the title!

4. Dec 1, 2007

### rocomath

LOL! Damn ... I've never seen it butchered that badly. Good laugh, thanks :-] no offense either :p

Last edited: Dec 1, 2007