Specify the problem

> ode1 := diff( x(t), t ) = x(t) * ( 10 - x(t) - y(t) );

> ode2 := diff( y(t), t ) = y(t) * ( 20 - 4*x(t) - y(t) );

> MODEL := { ode1, ode2 }:

> VARS := [ x(t), y(t) ];

> DOMAIN := t = 0 .. 1;

> RANGE := x=-5..15, y=-5..25;

> DIRplot := DEplot( MODEL, VARS, DOMAIN, RANGE, arrows=MEDIUM, title=`Nonlinear Direction Field` ):

> DIRplot;

Question