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Fllowing 1st order ODE describing the growth and decay of a population. a) Deter

ID: 1818704 • Letter: F

Question

Fllowing 1st order ODE describing the growth and decay of a population.

a) Determine if the equation is linear or non-linear and autonomous or non-autonomous. If linear, determine if the differential equation is homogeneous or non-homogeneous.

c) At what time will the population reach its maximum? Assuming the initial population is 5 million, what will the maximum population be?

d) According to this model, will the population every reach zero? Explain. Determine how long will it take for the population to reduce to 1 organism?

Explanation / Answer

dP/dt >0 for t<2

<0 for t>0

=> It is non autonomous

Variable separation and integrating

ln  p = 2t - t2/2 + ln c

P = C e2t - t^2/2

c= Po

P(t) = Poe(2t - t^2/2)

Max population

dp/dt = 0

2 = t

Max P = 5 e2 million = 36.95 m

For P->0

-(2t - t^2/2) -> 

t2/2 - 2t -> 

t2/2 - 2t is an increasing function for t>2 => It can reach 0 at an infinitely high value of t

P= 1

=>e(2t - t^2/2) =1/5

 

t2/2 - 2t =1.61

solve for t