e) Phase Plane and x- and y-solutions for the IVP

> ode1 := diff( x(t), t ) = 2*x(t) + 2*y(t) :

> ode2 := diff( y(t), t ) = -4*x(t) + 6*y(t) :

> MODEL := [ ode1, ode2 ] ;

> VAR := { x(t), y(t) } ;

>

> DOMAIN := t = 0 .. 1 ;

> WINDOW := x = -10 .. 10,

> y = -10 .. 10 ;

>

> IC := [ [x(0)= 1,y(0)= 1] ];

> PHASEplot := DEplot( MODEL, VAR, DOMAIN, WINDOW, IC, arrows = MEDIUM,

> title = `Phase Portrait for #4` ):

> PHASEplot;

>

> DOMAIN := t = 0 .. 2.5;

> P1:= DEplot( MODEL, VAR, DOMAIN, IC,

> scene=[ t, x ], arrows=NONE, linecolor=BLUE ):

> P2:= DEplot( MODEL, VAR, DOMAIN, IC,

> scene=[ t, y ], arrows=NONE, linecolor=GREEN ):

> display( [ P1, P2 ] , title = `x and y solution curves for # 4` );