Re: Annoying error in Hypergeometric2F1
- To: mathgroup at smc.vnet.net
- Subject: [mg107901] Re: [mg107888] Annoying error in Hypergeometric2F1
- From: Christoph Lhotka <christoph.lhotka at univie.ac.at>
- Date: Tue, 2 Mar 2010 07:52:59 -0500 (EST)
- References: <201003020835.DAA03959@smc.vnet.net>
sorry, but neither with V5, V6 or V7 I could reproduce your result. I get:
In[1]:= Hypergeometric2F1[1/2, 2, 3/2, -125/100]
Sqrt[5]
10 + 9 Sqrt[5] ArcTan[-------]
2
Out[1]= -------------------------------
45
In[2]:= %//N
Out[2]= 0.59836
In[3]:= Hypergeometric2F1[1/2, 2, 3/2, -1.25]
Out[3]= 0.59836
(the ArcTan instead of the ArcTanh)
Another question: I remember a definition, where 2F1(a,b,c,x) is defined
only for |x|<1. Does anybody know why / about the generalization?
chr
anguzman at ing.uchile.cl wrote:
> This is very bad and disappointing...what about version 7 ..
> Looks like the symbolic evaluation is messed up..
>
> Mathematica 6.0 for Linux x86 (32-bit)
> Copyright 1988-2008 Wolfram Research, Inc.
>
> In[1]:= Hypergeometric2F1[1/2, 2, 3/2, -125/100]
>
> Sqrt[5]
> 10 + 9 Sqrt[5] ArcTanh[-------]
> 2
> Out[1]= -------------------------------
> 45
>
> In[2]:= %//N
>
> Out[2]= 0.867836 - 0.702481 I
>
> In[3]:= Hypergeometric2F1[1/2, 2, 3/2, -1.25]
>
> Out[3]= 0.59836
>
>
>
> Atte. Andres Guzman
>
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- References:
- Annoying error in Hypergeometric2F1
- From: anguzman@ing.uchile.cl
- Annoying error in Hypergeometric2F1