# [Maxima] Solving a product?

Barton Willis willisb at unk.edu
Mon Aug 13 06:29:35 CDT 2007

```-----maxima-bounces at math.utexas.edu wrote: -----

>To: maxima at math.utexas.edu
>From: Steven Brown <swbrown at variadic.org>
>Sent by: maxima-bounces at math.utexas.edu
>Date: 08/13/2007 12:09AM
>Subject: [Maxima] Solving a product?
>
>I'm trying to use maxima to solve some product formulas, but having some
>trouble - note I'm not a very mathy person so I might be going about
>this all wrong.  An example of trying to solve a simple product formula:
>
>solve(product(k + 1, k, 1, n) = 720, n);
>
>I would expect to get something akin to "n = 5" out of it, but it never
>reduces even the simplest of product formulas it seems.  Is there a way
>to get that out of it?

Everything you did was OK; the problem is that Maxima isn't smart
enough to solve your equation. Even giving Maxima a big hint doesn't help:

(%i24) solve(n! = 6!);
(%o24) [n!=720]

In (%o24), Maxima returns the equation unsolved. Maybe your note will
motivate somebody to improve Maxima's solve function. There is
room (lots of room) for improvement:

(%i30) solve(abs(x)= 6);
(%o30) [abs(x)=6]

Thanks for your interest in Maxima.

Barton
```