% It would be nice to find a place in the rationalize code that makes

df(log((sqrt(a^2+x^2)+2*
   sqrt(sqrt(a^2+x^2)*a+a*x) + a + x)/(sqrt(a^2+x^2) - a + x)),x);

% come out in lowest terms, but would also make

limit(log((sqrt(x^(2/5) +1) - x^(1/3)-1)/x^(1/3)),x,0);

% run in reasonable time.

end;
