newbie question concerning recursion





On Fri, 24 Nov 2006, Miquel Cabanas wrote:

> hi,
>
> On Fri, 2006-11-24 at 12:02 +0100, Hugo Coolens wrote:
>>
>> Thanks for the quick reply, I changed the syntax as you suggested but
>> entering zth[2]; gives:
>>
>>   zth(1) s + 1
>>
>> ------------------
>>
>> (zth(1) + 1) s + 1
>>
>> and not:
>>
>> (1+2*s)/(1+3*s+s^2)
>
> try
>
> (%i12) radcan( zth[2] );
>
>                                   2 s + 1
> (%o12)                           ------------
>                                  2
>                                 s  + 3 s + 1
>
>
> Miquel
>
Even though the radcan function is available it doesn't do anything as you 
can see from the output below:
radcan( zth[2] );

           zth(1) s + 1
(%o89)
           ------------------

          (zth(1) + 1) s + 1

Any idea what's wrong?

hugo