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) + y(t)^2 :

> ode2 := diff( y(t), t ) = -x(t)/2+y(t)/5 - x(t)*y(t) + 6*y(t)^2/5 :

> MODEL := [ ode1, ode2 ] ; # define the differential equation model

> IC := [ x(0) = -0.5, y(0) = 0 ] ; # specify an initial condition in the form h(0)=200, u(0)=5

> VAR := { x(t), y(t) } ; # identify the variables in the model in the form h(t), u(t)

> DOMAIN := t = 0 .. 1.75;

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