Now I think I understand that the need for the so-called verb function: (%i1) :lisp(trace $cos); (%i1) ''cos(0); 0> Calling ($COS 0) <0 $COS returned 1 (%o1) 1 Hermite doesn't have a verb function: (%i2) ''hermite(1,x); (%o2) hermite(1, x) (%i3) hermite(1,x); (%o3) 2 x --Barton