LegendreP error (bug?) in Mathematica
- To: mathgroup at smc.vnet.net
- Subject: [mg58892] LegendreP error (bug?) in Mathematica
- From: "ab at sd.com" <at2 at ads.com>
- Date: Fri, 22 Jul 2005 01:58:42 -0400 (EDT)
- Sender: owner-wri-mathgroup at wolfram.com
Why does Mathematica give an erroneous answer to LegendreP[-1,1]=1? where it shoudl give -1 according to the series expansion below? is this a bug? In[13]:= LegendreP[-1, 1] Out[13]= 1 In[12]:= p[n_, z_] = (-1)^n* Sum[((Pochhammer[-n, k]*Pochhammer[n + 1, k])/k!^2)* ((z + 1)/2)^k, {k, 0, n}] Out[12]= n z + 1 (-1) Hypergeometric2F1[-n, n + 1, 1, -----] 2 In[16]:= p[-1, 1] Out[16]= -1