function ww = functionce(xx,c_ess,gamma,rho,p_hss,p_fss)
ww = [(gamma^(1/rho)*xx(1)^((rho-1)/rho)+(1-gamma)^(1/rho)*xx(2)^((rho-1)/rho))^(rho/(rho-1))-c_ess
       xx(1)/xx(2)-gamma/(1-gamma)*(p_hss/p_fss)^(-rho)
       ];

