th=0:0.001:2*pi;
z=zeros(3,length(th));
for i=1:length(th)
    t=th(i);
    A = [ cos(t)+4*sin(t)    sin(t)     1.7*sin(t) 
             sin(t)         4*sin(t)    1.7*sin(t)  
            1.7*sin(t)      1.7*sin(t)  6*sin(t)-cos(t)  ] ;
    z(:,i)=eig(A);
end
hold on
plot(th,z(1,:),'r')
plot(th,z(2,:),'b')
plot(th,z(3,:),'g')