kill(all)$

     Van - http://facebook.com/LearningCalculus

g(x):=1/(x*(x^2-1));

h(a,b,c,x):=a/x+b/(x-1)+c/(x+1);

g:ratsimp(g(x));

h:ratsimp(h(a,b,c,x));

ratsimp(h(-1,1/2,1/2,x));