function D=DPHI(x)

e=exp(-x(2)*x(2));
q=1+x(2)*x(2)+x(3)*x(3);

D=[e+x(3)           -2*x(2)*x(1)*e          x(1);...
   pi*cos(pi*x(1))  -1/((1+x(2))*(1+x(2)))  0;...   
   0                2*x(2)/q                2*x(3)/q]/6-eye(3);
