# [Maxima] I just wonder if there is difference equations support(package) in maxima

Xiang Liu hsiang.liu at gmail.com
Sat Feb 21 22:20:10 CST 2009

```Yes. but solve_rec just can solve linear difference equations and most
important, what I asked is "difference operator", which is the discrete
analogue of differential operator "diff "

I have defined my own difference operator, diff_rec means diff_recursive
(%i30) diff_rec2(exp,i):=subst(i+1,i,exp)-exp\$

(%i31) diff_rec2(x^m,m);
(%o31) x^(m+1)-x^m

(%i32) apply(diff_rec2,[%o28,m]);
(%o32) x^(m+2)-2*x^(m+1)+x^m

Now, I want to define a override function which has different parameters.
(???)
(%i36) diff_rec2(exp,i,n):=diff_rec2(diff_rec2(exp,i,n-1),i)\$
(%i37) diff_rec2(exp,i,1):=diff_rec2(exp,i)\$
Improper parameter in function definition for diff_rec2:
1
-- an error.  To debug this try debugmode(true);

I remembered that makelist has two forms:
*Function:* *makelist** (expr, i, i_0, i_1)* *Function:* *makelist** (expr,
x, list)*Can I define my own function which has different number of
parameters?

On Sat, Feb 21, 2009 at 3:37 AM, Martin Schönecker <ms_usenet at gmx.de> wrote:

> Searching for the terms: difference equation maxima in google, the
> second hit points to the tutorial
>
>
> http://maxima.sourceforge.net/docs/tutorial/en/gaertner-tutorial-revision/Pages/DiffEq0001.htm
>
> hth
>
> -Martin
>
> _______________________________________________
> Maxima mailing list
> Maxima at math.utexas.edu
> http://www.math.utexas.edu/mailman/listinfo/maxima
>
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