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Re: Sum command

  • To: mathgroup at smc.vnet.net
  • Subject: [mg128042] Re: Sum command
  • From: Rodrigo AP <digorna at gmail.com>
  • Date: Tue, 11 Sep 2012 02:32:09 -0400 (EDT)
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Thanks a lot, Bob!

2012/9/8 Bob Hanlon <hanlonr357 at gmail.com>

> iSum[expr_,
>   {x_Symbol, xmin_, xmax_, xstep_Integer: 1}] :=
>  Sum[expr, {x, Ceiling[xmin], Floor[xmax], xstep}]
>
>
> iSum[f[i], {i, 7/2, 4}]
>
> f[4]
>
>
> iSum[f[i], {i, 3/2, 2}]
>
> f[2]
>
>
> iSum[f[i], {i, 1/2, 9/2}]
>
> f[1] + f[2] + f[3] + f[4]
>
>
> iSum[f[i], {i, 1/2, 9/2, 2}]
>
> f[1] + f[3]
>
>
> Bob Hanlon
>
>
> On Sat, Sep 8, 2012 at 3:08 AM, Rodrigo AP <digorna at gmail.com> wrote:
> >
> > Dear group,
> >
> > How could I get: Sum[f[i],{i,7/2,4}]=f[4] or   Sum[f[i],{i,3/2,2}]=f[2]
> ? I
> > mean, I want the iterator running over the integers only ...
> >
> > Regards
> >
> > --
> > Rodrigo
> >
>



-- 
Rodrigo



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