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

[Michael Hudson]

Greg Ewing <see_reply_address at something.invalid> writes:

> 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.

That's about right.  You need some assumptions about the functions
involved.  An obvious one: they have to be differentiable.  I wonder
if they have to be analytic?  Probably not.

> There's no doubt some terribly good reason why this works,
> 
> but I can't remember it, if I ever knew...

Doesn't just need expanding both functions as a power series around
the limit point work?  (I guess you do need analyticity for this...)

Cheers,
M.
Who IS a mathematician, but IS NOT an analyst...

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