Direction Fields and Solution Curves
> ode1 := diff( x(t), t ) = ? * x(t) + ? * y(t) ;
> ode2 := diff( y(t), t ) = ? * x(t) - ? * y(t);
> MODEL := { ode1, ode2 }:
>
> VARS := { x(t), y(t) }:
> DOMAIN := t=0.. ? :
> RANGE := x= ? .. ? , y=- ? .. ? :
> dirPLOT := DEplot( MODEL, VARS, DOMAIN, RANGE, arrows=MEDIUM ):
> dirPLOT;
>
> IC := [ [ x(0)= ? , y(0)= ? ], [ x(0)= ? , y(0)= ? ], [ x(0)= ? , y(0)= ? ]: # use more or fewer than 3 IC's as necessary
> solPLOT := DEplot( MODEL, VARS, DOMAIN, RANGE, IC, arrows=NONE, linecolor=GREEN ):
> #solPLOT;
>
>
ICline := [ [ x(0)= ? , y(0)= ? ], [ x(0)= ? , y(0)= ? ],
[ x(0)= ? , y(0)= ? ], [ x(0)= ? , y(0)=- ? ] ]:
> linePLOT := DEplot( MODEL, VARS, DOMAIN, RANGE, ICline, arrows=NONE, linecolor=BLUE ):
> #linePLOT;
>
> display( [ dirPLOT, solPLOT, linePLOT ], title=` ??? ` ); # omit linePLOT for complex eigenvalues
>