% Nomenclature follows the perspective of the loop tf
n = conv([1 100],[1 200]);
d1 = conv([1 1],[1 2]);
d = conv(d1,[1 3]);

[q,denom] = polyder(d,n);
r = roots(q);

H = tf(n,d);
rlocus(-H);

K = polyval(d,r)./polyval(n,r);