Phase Portrait of Lotka-Volterra Equation
This Demonstration shows a phase portrait of the Lotka–Volterra equations, including the critical points. The eigenvalues at the critical points are also calculated, and the stability of the system with respect to the varying parameters is characterized.
The Lotka–Volterra equations are a pair of coupled differential equations
describing the dynamics of predator-prey populations, and , respectively.
 Wikipedia. "Lotka–Volterra Equations." (Jun 20, 2017) en.wikipedia.org/wiki/Lotka-Volterra_equations.