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ODE's

Many dynamical systems in physics, astronomy, chemistry, physiology, meteorology, economics, population
dynamics can be described by
Ordinary Differential Equations.
In the second half of the 20th century much attention has been focussed on the
often
chaotic,
i.e. unpredictable behaviour of (non-linear) ODE's. A well-known example is the
Lorenz atrractor, illustrating the "Butterfly effect": small causes can have large effects.
Mathgrapher uses an accurate Adams-Bashforth variable order, variable step predictor-corrector
algorithm to integrate systems of up to 20 coupled differential equations.

It is very easy to generate a phase portrait like the one shown below.
Just define the differential equations. In this case these are the equations
for a predator-prey model:

Push the Prepare / Draw graph button to open the graph window and the prepare window,
select the Analysis tab, choose phase portrait and push the Draw button.

The other analytical tools allow you to draw extra orbits (orbit in 2D),
find equilibrium points and calculate their stability properties (eigenvalues).
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