How to find z-transform of this sequence?

Hi all,

I am facing the following non-homework problem:

The sequence Pk for k=0, 1, 2, ...

has the Z-transform H(z).

And define another sequence by:

Qn=Sum( (k-s)*Pk, k from n to +infinity)

for n=0, 1, 2, ...

where s is a constant.

What should be the Z-transform of Qn sequence?

Thanks a lot! 

On 28 Jun., 05:47, "Vista" <a...@gmai.com> wrote:
> Hi all,
>
> I am facing the following non-homework problem:
>
> The sequence Pk for k=0, 1, 2, ...
>
> has the Z-transform H(z).
>
> And define another sequence by:
>
> Qn=Sum( (k-s)*Pk, k from n to +infinity)
>
> for n=0, 1, 2, ...
>
> where s is a constant.
>
> What should be the Z-transform of Qn sequence?
>
> Thanks a lot!

You can use two properties of the z-transform to solve this questions:
differentiation and linearity. Don't forget to subtract the terms Pk
for 0<=k<n.

Regards,
Andor

How ?


"Andor" <andor.bariska@gmail.com> wrote in message 
news:1183013860.620286.45440@q69g2000hsb.googlegroups.com...
> On 28 Jun., 05:47, "Vista" <a...@gmai.com> wrote:
>> Hi all,
>>
>> I am facing the following non-homework problem:
>>
>> The sequence Pk for k=0, 1, 2, ...
>>
>> has the Z-transform H(z).
>>
>> And define another sequence by:
>>
>> Qn=Sum( (k-s)*Pk, k from n to +infinity)
>>
>> for n=0, 1, 2, ...
>>
>> where s is a constant.
>>
>> What should be the Z-transform of Qn sequence?
>>
>> Thanks a lot!
>
> You can use two properties of the z-transform to solve this questions:
> differentiation and linearity. Don't forget to subtract the terms Pk
> for 0<=k<n.
>
> Regards,
> Andor
>