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?
>>>
>
>