% Routine 10.3  root locus
clear;
kmin=0;
kmax = 5;
N=10;
dk = (kmax-kmin)/N;
k = kmin:dk:kmax;
for n=1:N+1
 denom = [1,-3,2,5]+k(n)*[0,1,7,4];
 poles = roots(denom);
 re = real(poles);
 im = imag(poles);
 if n==1
  a=re;
  b= im;
 else
  a = [a;re];
  b = [b;im];
 end;
end;
plot(a,b,'x')