function F=fEXS715(x,U)
g=U(1)*exp(4*(1-U(1))/(1+0.2*(1-U(1))));
F=zeros(2,1);
F(1)=U(2);
if x==0
    F(2)=1/3*g;
else
    F(2)=-2/x*U(2)+g;
end