% x'=4x+2y-kx;
% y'=-26x-8y-17ky
%J mx=[4-k 2; -26 -17k-8]
% k=0; k=100; k=1;

k=1;
J=[4-k 2; -26 -17*k-8];
eig(J)
[trace(J) det(J)]

se=zeros(2, 0);
kend=10;
kkezd=0;
B=zeros(2, 0);
for k=kkezd:0.1:kend
    J=[4-k 2; -26 -17*k-8];
   % se=[se real(eig(J))];
    dj=det(J);
    tj=trace(J);
    B=[B [tj; dj]];
end
%plot(kkezd:0.1:kend, se');
T=min(B(1,:)):0.01:max(abs(B(1,:)));
D=T.^2/4;
plot(T,D);

