Consider the interaction of two species of animals in a habitat. We are told that the change of the populations $x(t)$ and $y(t)$ can be modeled by the equations $$\begin{array}{rcl} \displaystyle \frac{dx}{dt} & = & 0.4 x + 2 y, \cr & & \cr \displaystyle \frac{dy}{dt} & = & 5 x + 0.8 y. \end{array}$$

Symbiosis Competition Predator-prey  1. What kind of interaction do we observe?