Problems with PolyGamma

*To*: mathgroup at smc.vnet.net*Subject*: [mg22151] Problems with PolyGamma*From*: abdo at euroseek.com (Abds Roig)*Date*: Wed, 16 Feb 2000 02:35:16 -0500 (EST)*Organization*: The Math Forum*Sender*: owner-wri-mathgroup at wolfram.com

Hello. My name is Abdó Roig and I'm from Spain (sorry if my english isn't good). I've Mathematica 2.2 and I've found a problem with PolyGamma function. I was evaluating expressions like "PolyGamma[10^10]" and I found that the output of this expression is "- EulerGamma - 2Log2". This result is the same as the output of PolyGamma with integers near 10^10 or greater. Always is the same. I think it's wrong. If I use "N[PolyGamma[10^10]]" the output is -1.963......, the same. Then I tried to evaluate N[PolyGamma[10^10+1/10]], where 1/10 should not cause relevant changes on the result, but the output of this expression is 23.0259... (which seems to be a "correct" output). I think it's a bug of Mathematica. I would be very pleased if somebody could give me more information about it. Thanks. -- Abdo Roig abdo at euroseek.com