The derivative of %phi is zero because %phi is represents the number (1 + sqrt(5))/2 (the golden mean).
--Barton
-----maxima-bounces at math.utexas.edu wrote: -----
>Hi?everybody,
>
>Can?anybody?tell?me?if?there?is?something?wrong?here
>(%i0)?kill(all);
>(%i1)?'diff(p,t,1);?'diff(%theta,t,1);?'diff(r,t,1);?'diff(%phi,t,1);
>
>(%o1)?'diff(p,t,1)
>(%o2)?'diff(%theta,t,1)
>(%o3)?'diff(r,t,1)
>(%o4)?0
>
>Why?is?%04?zero?
>
>Thank?you?very?much
>