(a-b)^odd+ (b-a)^odd --/--> 0



Useful demonstration of a concrete expansion case, but the most
disappointing thing to my mind is that Maxima can't factor with *symbolic* *n
*without explicit preprocessing:
*
*
(%i2) ex: (b-a)^n+(a-b)^n$
(%i3) factor(ex);
(%o3) (b-a)^n+(a-b)^n      -- doesn't factor
(%i4) radcan(ex);
(%o4) (b-a)^n*(-1)^n+(b-a)^n   -- radcan canonicalizes (a-b) => (-1)*(b-a)
(%i5) factor(%);
(%o5) (b-a)^n*((-1)^n+1)     -- now we can factor symbolically

                -s

On Thu, Nov 18, 2010 at 10:03, Raymond Toy <toy.raymond at gmail.com> wrote:

> On 11/18/10 9:03 AM, Barton Willis wrote:
> > -----maxima-bounces at math.utexas.edu wrote: -----
> >
> >> bonjour
> >> factor((a-b)^10001 + (b-a)^10001)  ---->  0
> >> jean
> > Thanks--I didn't think about factor. But
> >
> >  (%i5) factor((a-b)^10001 + (b-a)^10001 + 1);
> >  Maxima encountered a Lisp error:
> Interesting.  What version and lisp?  With the CVS version on cmucl, I
> get 1.
>
> Ray
>
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