SIR Epidemic Model Dynamic Simulation

This GeoGebra example dynamically simulates the classic SIR epidemic model, illustrating the time evolution of three population compartments: Susceptible (S), Infected (I), and Recovered (R). The core mathematical concept is a system of ordinary differential equations, solved numerically using the NSolveODE command<｜begin▁of▁file｜>. Key parameters such as transmission rate (a), recovery rate (k), and initial values (Sstart, Istart, Rstart) are controlled via sliders, allowing exploration of the basic reproduction number R0 and its impact on outbreak dynamics. The construction uses GeoGebra's differential equation solver, dynamic text objects to display metrics like peak infection (Imax), and plots the three curves simultaneously. This resource is suitable for high school to university courses in mathematics, epidemiology, or mathematical biology, helping students understand epidemic spread, threshold phenomena, and parameter sensitivity.