\(\frac{dS}{dt}=-rSI+S\mu\ \)
\(\frac{dI}{dt}=rSI-kI\ \)

Question 2

Let  \(x=x\left(t\right)\) be the number of thousands of animal species A at time t.
Let  \(y=y\left(t\right)\) be the number of thousands of animal species B at time t.\(\)