extracting common terms



On Sat, 07 Mar 2009 20:56:57 -0600, Barton Willis wrote:

Unfortunately, it doesn't work.  I simplified to a toy example:

(%i1) exp: u(e)^(a-1)*v(e)^(1-a)+u(e)^a*v(e)^a;
                        a     a          a - 1     1 - a
(%o1)                  u (e) v (e) + u(e)      v(e)
(%i2) facsum(diff(exp,e),diff(v(e),e), diff(u(e),e));
           a + 1     - a - 1             2 a                   d
(%o2) (u(e)      v(e)        (a u(e) v(e)    - a v(e) + v(e)) (-- (v(e)))
                                                               de
                       a                2 a                   d
                      u (e) (a u(e) v(e)    + a v(e) - v(e)) (-- (u(e)))
                                                              
de           2
                    + --------------------------------------------------)/
u (e)
                                             a
                                            v (e)

What I would like to get as the result is the coefficients for v_e and
u_e, ie

[(1-a)*u(e)^(a-1)*v(e)^(-a)+a*u(e)^a*v(e)^(a-1),
 (a-1)*u(e)^(a-2)*v(e)^(1-a)+a*u(e)^(a-1)*v(e)^a];

I am sure Maxima can do this easily, I just don't know how to achieve 
it:-)

Tamas