Re: Series holding the final sum

• To: mathgroup at smc.vnet.net
• Subject: [mg117791] Re: Series holding the final sum
• From: Heike Gramberg <heike.gramberg at gmail.com>
• Date: Thu, 31 Mar 2011 04:04:08 -0500 (EST)

```It's probably cheating a little, but what about

(Sum[(-1)^(n + 2) x^(2 n + 1)/(2 n + 1), {n, 0, 5}] /. x -> -y) /.
y -> HoldForm[1]

Heike

On 30 Mar 2011, at 11:10, Jon Joseph wrote:

> All:  Given the following sum:
>
> Sum[(-1)^(n + 2) x^(2 n + 1)/(2 n + 1), {n, 0, 5}]
>
> which generates:
>
> x - x^3/3 + x^5/5 - x^7/7 + x^9/9 - x^11/11
>
> I would like to replace x with -1 (%/.x->-1) without the sum being evaluated so I end up with
>
> -1+1/3-1/5+1/7-1/9+1/11
>
> So far I have not been able to find a way to Hold, HoldForm, Unevaluate, or Defer and keep getting -2578/3465.  Thanks. Jon
>

```

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