another question



I would like to calculate the partial sums of a fourier series and have 
maxima do the work. So, I define an array of functions (well, that is my 
intent)
f[0](x):=0;
for i:1 thru 10 do 
f[i+1](x):=f[i](x)+(-1)^i/(2*i+1)^2*sin(%pi*x/(2*i+1)^2). Then, I would 
plot the partial sums via plot2d.

However, both commercial Macsyma and maxima, while perfectly happy with 
a subscripted definition such as f[0](x):=x, they complain when I try to 
do this in a for loop.  maxima gives the error message:
ERROR ((MPLUS) |$i| 1) is not of type STRING

Is there a way to overcome this difficulty? Thanks,
Dick Fell