function [s,mu] = korrektur(F,DF,x,mu,beta0,beta1)

 n=length(x);
 s=-(DF(x)'*DF(x)+mu^2*eye(n))\(DF(x)'*F(x));
 eps_mu=(F(x)'*F(x)-F(x+s)'*F(x+s))/(F(x)'*F(x)-(F(x)+DF(x)*s)'*(F(x)+DF(x)*s));

    if eps_mu <= beta0
       [s,mu]=korrektur(F,DF,x,2*mu,beta0,beta1)
    elseif eps_mu >= beta1
        mu=mu/2;
    end
end