III.2 Malthusian Growth

Thomas Malthus (1766-1834) is generally credited with the idea that populations tend to grow exponentially.  Exponential growth (or decay) occurs whenever the rate of change over time of a variable is directly proportional to the value of the variable.  To see this in Mathematica, we use   as the constant of proportionality.

We can plot several solution curves at once to see the behavior of the solutions.

ADVANCED
III.2.1a Experiment with different and values. Give an interpretation of and in terms of population growth (e.g. birth rate and death rate).