PolyGamma - series expansions
- To: mathgroup at smc.vnet.net
- Subject: [mg41658] PolyGamma - series expansions
- From: dougaler at uboot.com (dougaler)
- Date: Thu, 29 May 2003 08:15:36 -0400 (EDT)
- Sender: owner-wri-mathgroup at wolfram.com
I want to expand lots of things like
(Gamma[n+f[s]])^(-1) D[ Gamma[n+f[s]] ,s] as n->Infinty
Mathematica gives an asymptotic power series for the digamma function:
In: Series[PolyGamma[n], {n, Infinity, 2}]
Out: -Log[1/n]-1/2n+O[1/n^2]
However, it does not like:
Series[PolyGamma[2n], {n, Infinity, 2}]
or
Series[PolyGamma[n+2], {n, Infinity, 2}]
Can anyone tell me why this is or suggest any neat remedies?
Thanks very much.