[Python-Dev] PEP239 (Rational Numbers) Reference Implementation and new issues

[Fernando Pérez]

Greg Ewing wrote:

> Fernando Pérez wrote:
> 
>> Chad Netzer wrote:
>> 
>> In expressions that go to 0/0,
>> you need to figure out which one (num/den) goes faster to 0 to be able to
>> answer. Long faded memories of calc. classes trickle in ...
> 
> 
> My own faded memory says: L'Hopital's Rule. Differentiate top
> and bottom and take the limit of that instead. Repeat until
> top and bottom don't both go to 0.
> 
> 
> There's no doubt some terribly good reason why this works,

Yes, basically by using L'Hopital's you are getting explicitly what the 
next-to-leading order behavior is (think of the power series expansion of 
each of num/den, and then differentiate that).

cheers,

f.