> #maple1b using dsolve( numeric) instead of DEplot
> with(plots):
> ODE1:=diff(x(t),t)=-y(t);
> ODE2:=diff(y(t),t)=x(t);
> SYS:=[ODE1,ODE2,x(0)=1,y(0)=0];
> dsn:=dsolve(SYS,numeric,range=0..6.2,initstep=0.1);
> XvsT:=odeplot(dsn,[t,x(t)],t=0..6.2,color=blue):
> YvsT:=odeplot(dsn,[t,y(t)],t=0..6.2,color=green):
> DvsT:=odeplot(dsn,[t,x(t)*x(t)+y(t)*y(t)],t=0..6.2,color=red):
> display(XvsT,YvsT,DvsT);
> odeplot(dsn,[x(t),y(t)],t=0..6.2);
> 
>