Re: Mathematica 8 does not like Sum[1/k,{k,n,10}]
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- Subject: [mg130771] Re: Mathematica 8 does not like Sum[1/k,{k,n,10}]
- From: Bob Hanlon <hanlonr357 at gmail.com>
- Date: Mon, 13 May 2013 03:48:43 -0400 (EDT)
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Without giving n a specific value in your definition, Mathematica has no way of knowing that you intend n to be an integer in the range [1, 8]. $Version "8.0 for Mac OS X x86 (64-bit) (October 5, 2011)" f1[n_Integer?(0 < # < 9 &)] := Sum[1/k, {k, n, 8}] f2[n_Integer?(0 < # < 9 &)] := Sum[1/k, {k, 8, n, -1}] Table[f1[n] == f2[n] == Sum[1/k, {k, n, 8}], {n, 0, 9}] // Quiet {f1[0] == f2[0] == ComplexInfinity, True, True, True, True, True, True, True, True, f1[9] == f2[9] == 0} Bob Hanlon On Sun, May 12, 2013 at 3:29 AM, valvola <g.resta at iit.cnr.it> wrote: > Apparently, Mathematica 8 does not like the simple expression: > > Clear[k,n]; Sum[1/k,{k,n,8}] > > The result is two errors: > Power::infy: "Infinite expression 1/0 encountered." > > and a large expression > DifferenceRoot[ > Function[{\[FormalY], \[FormalN]}, {\[FormalN] \ > \[FormalY][\[FormalN]] + .... etc.etc. > > By the way, the similar Sum[1/k, {k, 8, n}] works fine. > > ???? > g. > >
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- Mathematica 8 does not like Sum[1/k,{k,n,10}]
- From: valvola <g.resta@iit.cnr.it>
- Mathematica 8 does not like Sum[1/k,{k,n,10}]