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 ) = y(t) ;

> ode2 := diff( y(t), t ) = (1-x(t)^2)*y(t) - x(t) ;

> MODEL := [ ode1, ode2 ] ;

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

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

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