If it is not in maxima, you can define (from macsyma 2.4)
GENFACT(X, Y, Z)
as the generalized factorial of X which is:
X*(X-Z)*(X-2*Z)*...*(X-(Y-1)*Z).
defining simplification methods is tricky. Do you
know how to do this mechanically by hand?
If so, try to write a program for that purpose.
RJF
wang yin wrote:
> Hi,
>
> I'm trying to to do some finite calculus with MAXIMA.
> But I don't know how to express "x to the m falling",
> i.e., x(x-1)(x-2)...(x-m+1) in MAXIMA conveniently.
>
> Is MAXIMA aware of this notation?
>
> If I express "k to the m falling" as k!/(k-m)! in nusum, I
> get:
>
> (C1) nusum(k!/(k-m)!,k,0,n);
>
> (n + 1)! m
> (D1) ---------------- + --------------
> (m + 1) (n - m)! (m + 1) (- m)!
>
> How can I abtain the desired result
>
> "n to the (m+1) falling"/(m+1) ?
>
>
>
> --
> Wang Yin
> Deparment of Computer Science and Technology,
> Tsinghua University,
> 100084
> Beijing China
>
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