function fpx = fp3(  x )
  fpx = zeros(2,1);
  a = 1.0;
  b = 100.0;
  fpx(1) = - 2.0 * ( a - x(1) ) - 4.0 * b * ( x(2) - x(1).^2 ) .* x(1);
  fpx(2) = 2.0 * b * ( x(2) - x(1).^2 );
  return
end

