On 5/3/10 3:57 AM, John Lapeyre wrote:
> On Monday 03 May 2010 04:51:53 Raymond Toy wrote:
>
>
>> gg : x^3+t*x^2-3*x-2*t$
>> lsum(gg*t,t,rootsof(t^2+1));
>> ->
>> ?%lsum(gg*t,t,rootsof(t^2+1))$
>> Shouldn't gg be substituted? How can I do this?
>>
> I think your problem is in the list:
>
> (%i1) gg : x^3+t*x^2-3*x-2*t$
> (%i2) rts : [-%i,%i]$
> (%i3) lsum(gg*t,t,rts);
> (%o3) 0
>
I made a typo. The actual expression should have been
lsum(log(gg)*t,t,rts). This still evaluates to zero.
Robert has provided the right answer, I think.
Ray