Beginner 'apply' question



Thanks Stavros/Robert/Mario!  You've shown me several ways to get done 
what I wanted.  More importantly, you've opened my eyes to the fact that 
Maxima is not only a program written in Lisp but one that can be be used 
with Lispy mindset which I hadn't considered.

Thanks,
Phil

Stavros Macrakis wrote:
> On 12/29/06, Phil <pbpublist at comcast.net> wrote:
>> e1: a^2+b^2=c^2;
>> apply(rhs(first(solve (e1, b))), [3, 5]);
> 
> Thanks for your interest in Maxima!
> 
> There are a couple of things to note here.
> 
> First of all, "apply" applies functions to arguments, either named
> functions (like sin or f where f(x):=x^2) or lambda-expressions.
> Solve does not return a function, it returns a list of solutions,
> where each solution is a list of equations.
> 
> The best and simplest way to substitute values for variables is the
> subst function:
> 
>        subst([a=3,c=5], solve(e1,b))
> 
> I would not recommend using "ev" and " ' '  " (two single-quotes),
> because their use can be tricky and surprising.  As a general rule, if
> it can be done with "subst", I would recommend doing it with subst,
> not ev or other mechanisms.
> 
>             -s