kill(all)$

van=facebook.com/LearningCalculus$

f(a,b):=fullratsimp(1/a+1/(2*a)+1/(3*a)=1/(b^2-(2*b)))$ f(a,b);

1/f(y,x);

y(x):=(11*(x^2-2*x))/6;

''(diff(y(x),x))=0;

solve(%,x);

y(1);

f(-11/6,1);

-11/6+-1;