displaying a function



Dear list,

Still taking my first steps with Maxima and definitely refusing
to resort to Maple, I am setting up some simple examples before I
try to implement the bigger thing that I am working on.  The
purpose for me is to get a feel for and try to understand how
Maxima works.

Consider the following example where I have an s-dimensional
function f(x) from which i create a new s-dimensional function
f_periodized(x) by using a certain recursion:


s: 2$
f(x) := product(x[i]^i, i, 1, s)$

phi[0](x) := f(x)$
for j:1 thru s do
  phi[j](x) := phi[j-1](x) + f(x)$
  
dispfun(phi[s])$

f_periodized(x) := phi[s](x)$
dispfun(f_periodized)$


Starting from an arbitrary f(x), I would like to see how f_periodized(x)
looks like.  For my given example, the dispfun(phi[s]) command gives me

                                            s
                                               2
(%t6)                         phi (x) := 3 x  x
                                 s          1  2


Which is what I need.  However, the dispfun(f_periodized) command only gives

(%t8)                     f_periodized(x) := phi (x)
                                                s

Why is this and how can i also display f_periodized(x) in terms of the x_i?

Thanks,
Bart

-- 
	"Share what you know.  Learn what you don't."