Answer:
[tex]P'(t) = 19P(1 - \frac{P}{8000}) - 9[/tex]
Step-by-step explanation:
The logistic equation is given by Equation 1):
1) [tex]\frac{dP}{dt} = rP(1 - \frac{P}{N})[/tex]
In which P represents the population, [tex]\frac{dP}{dt} = P'(t)[/tex] is the variation of the population in function of time, r is the growth rate of the population and N is the carrying capacity of the population.
Now for your system:
The problem states that the population has growth rate r=19.
The problem also states that the population has carrying capacity N=8000.
We can replace these values in Equation 1), so:
[tex]P'(t) = 19P(1 - \frac{P}{8000})[/tex]
However, beginning in 2000, 9 citizens of Cook Island have left every year to become a mathematician, never to return. So, we have to subtract these 9 citizens in the P'(t) equation. So:
[tex]P'(t) = 19P(1 - \frac{P}{8000}) - 9[/tex]