The relative growth rate of a population P(t) of koalas is given in the graph be
ID: 2833613 • Letter: T
Question
The relative growth rate of a population P(t) of koalas is given in the graph below,
where t is years since 1900. Use this information to nd the perecentage increase (or decrease) in
koala population between 1900 and 1960. (You must explain in complete detail why the integral
you take is equal to what you say it is: justify every step!)
Explanation / Answer
integral of dP/dt/P dt = integral of dP/P = ln(Pf/Pi)
integral of P'/P dt = 20*-0.02 + 20*-0.02/2 + 40*0.02/2=-0.2
so Pf/Pi = e^(-0.2)
percentage change = (Pf-Pi)/Pi = Pf/Pi -1 = e^(-0.2)-1=-0.181