function jac = jacosborne(p)
  n=33;
  m=5;

  for i=1:n
    t=10*(i-1);
    tmp1=exp(-p(4)*t);
    tmp2=exp(-p(5)*t);

    jac(i, 1:m)=[1.0, tmp1, tmp2, -p(2)*t*tmp1, -p(3)*t*tmp2];
  end
