# [Maxima] confusing solution set of exp-equation

Wolfgang Lindner LindnerW at t-online.de
Tue Apr 17 09:17:00 CDT 2007

```<sen1 at math.msu.edu> schrieb:
> The 'expression based' system of maxima has its charm.
> Consider the following.
> %i26) f: x^3;
>                                         3
> (%o26)                                x
> (%i27) df(x):= diff(f,x);
> (%o27)                        df(x) := diff(f, x)
> (%i28) val(f,t):= subst(x=t,f);
> (%o28)                   val(f, t) := subst(x = t, f)
> (%i29) f: x^4;
>                                         4
> (%o29)                                x
> (%i30) df(x);
>                                          3
> (%o30)                               4 x
> (%i31) val(f,2);
> (%o31)                                16
> (%i32) val(df(x),5);
> (%o32)                                500

Thanks, Sheldon, in addition to the other hints I am very happy with the solution now.
Your advice is in my opinion best combined with the abbreviate use of ev()=.,. (see J.
Villate) Thx you all.

HTH Wolfgang
```