In this editor systems of ordinary differential equations of first order are defined.
That means that a system of equations that contains second derivatives must be recast to a system of equations with only first derivatives. This demand is not restrictive, as any system of equations with second derivatives in it can expressed equivalently as a system of equations with only first derivatives, by introducing auxillary variables as needed.
The button ‘Prelim’ opens a panel for repeatedly occuring elements in the Evolution calculation. This feature is for making the calculations more efficient.
The ‘Solver’ selection combobox allows you to choose which of the solver algorithms provided by EJS you want to use to solve numerically the ODE.
The button ‘Events’ opens a panel for evaluating non-smooth changes in the evolution, such as a ball bouncing on a floor.