Re: Newbie question: equations with sums.

*To*: mathgroup at smc.vnet.net*Subject*: [mg92879] Re: [mg92856] Newbie question: equations with sums.*From*: Bob Hanlon <hanlonr at cox.net>*Date*: Thu, 16 Oct 2008 05:06:53 -0400 (EDT)*Reply-to*: hanlonr at cox.net

(Sum[i*f[i], {i, 0, -1 + n}] /. i -> k) == Sum[k*f[k], {k, 0, -1 + n}] True Bob Hanlon ---- Vend <vend82 at virgilio.it> wrote: ============= Hello. FullSimplify[\!\( \*UnderoverscriptBox[\(\[Sum]\), \(i = 0\), \(\(-1\) + n\)]i\ f[ i]\) == \!\( \*UnderoverscriptBox[\(\[Sum]\), \(k = 0\), \(\(-1\) + n\)]k\ f[k]\)] Evaluates to: \!\( \*UnderoverscriptBox[\(\[Sum]\), \(i = 0\), \(\(-1\) + n\)]i\ f[ i]\) == \!\( \*UnderoverscriptBox[\(\[Sum]\), \(k = 0\), \(\(-1\) + n\)]k\ f[k]\) Why doesn't it evaluate to true? Is there a way to make the system solve this kind of equations? -- Bob Hanlon