-----maxima-bounces at math.utexas.edu wrote: -----
>I'm still new to Maxima ... I would like use Maxima to write out the
>mixed directional derivatives like (grad(grad C).a).b, where a and b are
>vectors and C(x,y,z) is a scalar function.
Define a function grad:
(%i4) grad(e,v) := makelist(diff(e,vk),vk,v)$
Represent a vector as a list; the dot product is a period:
(%i5) grad(grad(x^2+x*y + z^2,[x,y,z]) . [1,2,3],[x,y,z]).[2,4,5];
(%o5) 42
Also
(%i6) grad(f(x,y,z),[x,y,z]);
(%o6) ['diff(f(x,y,z),x,1),'diff(f(x,y,z),y,1),'diff(f(x,y,z),z,1)]
There is a Maxima package for vector calculus using non-cartesian
coordinates.
Actually, I think there is more than one package---I haven't looked at them
for a long time. Maybe somebody else can give you advice about which one to
try.
Welcome to Maxima.
Barton