> with(linalg):

Warning, new definition for norm

Warning, new definition for trace

> z1:=c1*exp(-2*t);z2:=c2*exp(-4*t);

> linspace:=(a,b,n)->[seq(a+i*(b-a)/n,i=0..n)];

Warning, `i` in call to `seq` is not local

> Z2:=C*Z1^2;

> X:=matrix(2,2,[1,1,1,-1]);

> Y:=evalm(X&*vector([Z1,Z2]));

> kay:=C->plot([Z1+C*Z1^2, Z1-C*Z1^2,Z1=-3..3],color=blue):

> with(plots):

> display(kay(1));

> parvi:=display([seq(kay(C),C=linspace(-1,1,10))]):

> sys:=diff(y1(t),t)=-3*y1(t)+y2(t),diff(y2(t),t)=y1(t)-3*y2(t);

> with(DEtools):

> sk:=DEplot([sys],[y1(t),y2(t)],t=-5..5,y1=-4..4,y2=-5..5):

> display([parvi,sk]);

>

>