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 >