grouping the variables in a certain way



Daniel Lakeland wrote:

> On Fri, Jun 15, 2007 at 11:02:51PM -0400, Kamaraju S Kusumanchi wrote:
>> Richard Fateman wrote:
>> 
>> > ratsubst(q,x/D^2,a);
>> > factor(%);
>> > ratsubst(x/D^2,q,%);
>> >  
>> > Does it. Gives
>> > -(x/D-1)*(x/D+1)/(3*x/D+1)^4
> ...
>> Doesnot seem to work. I am getting
>> 
>> (%i4) ratsubst(x/D^2,q,%);
>>                                    4    2  2
>>                                   D  - x  D
>> (%o4)             ------------------------------------------
>>                    4         3       2  2        3         4
>>                   D  + 12 x D  + 54 x  D  + 108 x  D + 81 x
> 
> if you replace the second ratsubst with subst(q=x/D^2,%) it works for
> me.
> 

Ok. This also works. Thanks

raju

-- 
Kamaraju S Kusumanchi
http://www.people.cornell.edu/pages/kk288/
http://malayamaarutham.blogspot.com/