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Re: Hypergeometric2F1 gives wrong complex infinities

• To: mathgroup at smc.vnet.net
• Subject: [mg100896] Re: Hypergeometric2F1 gives wrong complex infinities
• From: Jens-Peer Kuska <kuska at informatik.uni-leipzig.de>
• Date: Thu, 18 Jun 2009 04:49:06 -0400 (EDT)
• Organization: Uni Leipzig
• References: <h19i96$p8o$1@smc.vnet.net>
• Reply-to: kuska at informatik.uni-leipzig.de

Hi,


Hypergeometric2F1[1, I, I + 1, -Exp[a]] /. a -> 36
gives

Hypergeometric2F1[I, 1, 1 + I, -E^36]

and N[]

-0.0348098 + 0.269793 I

so, *what* have you put into Mathematica ?

Regards
   Jens

Wieland Brendel wrote:
> Dear all!
> I currently have a problem with the hypergeometric function: Consider
> 
> Hypergeometric2F1[1, I, I + 1, -Exp[a]]
> 
> Whenever I set a > 36 I only get "complex infinity" as a result although 
> it should be perfectly finite (take 10 as a scale). Is there any way to 
> expand the range of a to higher values?
> 
> I would be very thankful for a solution! A big thanks in advance and 
> best greetings from germany!
> 
> Wieland Brendel
> 
> PS: I use Mathematica 7.
>