Re: Solve equation with summation?

*To*: mathgroup at smc.vnet.net*Subject*: [mg122998] Re: Solve equation with summation?*From*: Ralph Dratman <ralph.dratman at gmail.com>*Date*: Sun, 20 Nov 2011 05:35:14 -0500 (EST)*Delivered-to*: l-mathgroup@mail-archive0.wolfram.com*References*: <ja5f56$69e$1@smc.vnet.net>

I see the discrepancy on my copy of 8.0.4 too. Ralph On Sat, Nov 19, 2011 at 6:48 AM, Bob Hanlon <hanlonr357 at gmail.com> wrote: > Not with my version > > $Version > > "8.0 for Mac OS X x86 (64-bit) (October 5, 2011)" > > Solve[Sum[Subscript[a, i], {i, 1, n}]/x == 1, x] > > {{x -> Sum[Subscript[a, i], {i, 1, n}]}} > > Solve[Sum[Subscript[a, i]/x, {i, 1, n}] == 1, x] > > {} > > > Bob Hanlon > > > On Fri, Nov 18, 2011 at 7:50 AM, Dr. Wolfgang Hintze <weh at snafu.de> wrote: >> Sorry, but with me both expressions (exactly copied from your message) >> give the same result. >> Regards, >> Wolfgang >> >> "Ivan" <iveney at gmail.com> schrieb im Newsbeitrag >> news:ja5f56$69e$1 at smc.vnet.net... >>> For a summation like \sum_{i=1}^n a_i/x = 1, >>> >>> Solve[Sum[Subscript[a, i], {i, 1, n}]/x == 1, x] >>> >>> gives a correct solution. >>> >>> However, by putting x into the summation: >>> >>> Solve[Sum[Subscript[a, i]/x, {i, 1, n}] == 1, x] >>> >>> >>> gives an empty set, why? >>> > >