Sum and NSum problem
- To: mathgroup at smc.vnet.net
- Subject: [mg106888] Sum and NSum problem
- From: deepblue <contato34 at gmail.com>
- Date: Tue, 26 Jan 2010 06:34:38 -0500 (EST)
Mathrematica v7
1) Resulting function resturns k
Sum[(x^k/k!)^k, {k, 1, Infinity}]
-(x^k/(x^k - k!))
2)NSum worses the approximation of zeta function
eexp[x_, n_: 30] :=
1 + Sum[(x)^k/k!, {k, 1, n}]; (*exponential function definition*)
nzzeta[s_] := NSum[eexp[-s Log[k]], {k, 1, 60}];
nzzeta[2]
75.3061
zzeta[s_] := Sum[eexp[-s Log[k]], {k, 1, 60}];
zzeta[2.]
1.62842
Zeta[2.]
1.64493
Are these examples bugs? thanks