Modeling Population Growth?
The rate of growth of a population is proportional to its present size, and the population of a city is currently 100,000. If the growth rate is 0.02 per year, estimate the population after 5 years using the differential equation dP/dt = kP, where P is the population and k is the growth rate.
1 Answer
📌 CONCEPT: The differential equation dP/dt = kP models population growth when the rate of growth is proportional to the present size of the population.
📐 RULE / FORMULA: The general solution to this differential equation is P(t) = P0 * e^(kt), where P0 is the initial population and k is the growth rate.
💡 WORKED EXAMPLE: Given P0 = 100,000 and k = 0.02, we can estimate the population after 5 years as P(5) = 100,000 * e^(0.02*5) ≈ 100,000 * e^0.1 ≈ 113,295.
⚠️ COMMON MISTAKE: Students often forget to use the initial population (P0) in the general solution, leading to incorrect estimates of population growth.
24 Sept 26
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