Re: Expansion symbolic
- To: mathgroup at smc.vnet.net
- Subject: [mg74797] Re: Expansion symbolic
- From: dh <dh at metrohm.ch>
- Date: Thu, 5 Apr 2007 04:15:56 -0400 (EDT)
- Organization: hispeed.ch
- References: <euvm0k$cc5$1@smc.vnet.net>
Hi Dominic,
try: ...//TraditionalForm
Note, that output from TraditionalForm can not necessarily given as
input to Mathematica.
Daniel
Dominic Jackson wrote:
> Could anyone please tell me how to instruct Mathematica to expand the
> expression below with respect to the powers of x. I would like the
> constants c1,c2,c3 and c4 to stay behind the summation sign but the powers
> of x to cross over to multiply x^(k+i).
>
>
>
> (c1 (x^2) +c2 (x^3))* D[(Summation sign i=0 to infinity) Subscript[a,i+1][k]
> * x^(k+i),{x,2}]//Expand.
>
>
>
> This is what I get
>
>
>
> c1 x^2 *(Summation sign i=0 to infinity) (k+i)*(k+i-1) *Subscript[a,i+1][k]
> * x^(k+i-2)
>
>
>
> + c2 x^3 *(Summation sign i=0 to infinity) (k+i)*(k+i-1)
> *Subscript[a,i+1][k] * x^(k+i-2)
>
>
>
> And this is what I want to achieve.
>
>
>
> c1 *(Summation sign i=0 to infinity) (k+i)*(k+i-1) *Subscript[a,i+1][k] *
> x^(k+i)
>
>
> + c2 *(Summation sign i=0 to infinity) (k+i)*(k+i-1) *Subscript[a,i+1][k] *
> x^(k+i+1)
>
> Any clues.
> Thanx.
>
> Dom
>