Defining the model
All differential equation models begin with a differential equation. If the problem is an intial value problem, an initial condition is also needed. Replace the question marks ( %? ) in the following input regions to define the relevant ODE model.
> ode1 := diff( x(t), t ) = 2*x(t) + y(t) :
> ode2 := diff( y(t), t ) = -y(t) :
> MODEL := [ ode1, ode2 ] ;
> IC := [ x(0) = 1, y(0) = -1 ] ;
> VAR := { x(t), y(t) } ;
>