# Proof of l'hopital's rule ? [closed]

We all know l'hopital's rule ! But what is its proof ?!!

I guess that not all people know its proof ! Do they ?

Can any one give a proof for it ? Starting with the simplest one . L'hopital's rule is very important for calculating limits and was discovered by a french mathematician , M.l'hopital !

So I'm interested to know the proof of this great theorem. Isn't it a great theorem ? Thanks !

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open up any textbook on calculus and you will find such a proof. – Ittay Weiss Jan 27 at 23:54
@IttayWeiss , i look for many proofs , simple ones and hard ones ! – Maths Lover Jan 27 at 23:58
See e.g. en.wikipedia.org/wiki/… – Robert Israel Jan 28 at 0:00
It is very likely that the Rule was discovered by Johann Bernoulli. – André Nicolas Jan 28 at 0:01
@AndréNicolas , and why was it called l'hopital rule ? – Maths Lover Jan 28 at 0:07

## closed as not a real question by Ittay Weiss, TMM, rschwieb, Clive Newstead, ncmathsadistJan 28 at 0:25

It's difficult to tell what is being asked here. This question is ambiguous, vague, incomplete, overly broad, or rhetorical and cannot be reasonably answered in its current form. For help clarifying this question so that it can be reopened, see the FAQ.

MathsLover visit wikipedia for a good proof.

See this youtube clip for a clip of the proof.