-----maxima-bounces at math.utexas.edu wrote: -----
>Define
> a=f1(x,y,z,a,b)
> b=f2(x,y,z,c,d)
>x,y,z are independent variables
>a-d are symbolic constants
>
>I would like to symbolically evaluate (a+b) or (a-b)
Maybe you want to define f1 and f2 to
be functions; you can do that with the inputs:
(%i1) f1(x,y,z,a,b) := (x-a)^2 + (y-b)^2 + z^2$
(%i2) f2(x,y,z,c,d) := (x-c)^2 + (y-d)^2 + z^2$
To compute f1(x,y,z,a,b) - f2(x,y,z,c,d), use
(%i3) f1(x,y,z,a,b) - f2(x,y,z,c,d);
(%o3) -(y-d)^2+(y-b)^2-(x-c)^2+(x-a)^2
To expand and cancel like terms, use the function 'expand'
(%i4) expand(%);
(%o4) 2*d*y-2*b*y+2*c*x-2*a*x-d^2-c^2+b^2+a^2
Maybe this helps---I'm partially guessing about what you want to do.
Another thing--the Maxima assignment operator is the colon, not equal.
Barton