Re: Is it possible to impose a condition on an iterator of the summation ?
- To: mathgroup at smc.vnet.net
- Subject: [mg101575] Re: Is it possible to impose a condition on an iterator of the summation ?
- From: Bill Rowe <readnews at sbcglobal.net>
- Date: Fri, 10 Jul 2009 06:47:23 -0400 (EDT)
On 7/9/09 at 1:52 AM, mauro at NONOyahoo.com (Mauro) wrote:
>I would like to perform a summation of this type,
>Sum[a^2 - 3 a/(4 a^2), {a, 1, 20}]
>excluding however some values of the iteratore, I would for instance
>like to exclude the values than to greater of 6 and inferior to 12.
>Is it possible?
I sounds like you want to do the sum for a = 7 to 11 which is
easily done as:
Sum[a^2 - 3 a/(4 a^2), {a, 7, 11}]
But since this seems so obvious, perhaps I've misunderstood your issue.