AP Calculus BC · Question of the Day

AP Calculus BC Question of the Day

A fresh daily question to build accuracy, reinforce recall, and turn practice into a steady habit.
Monday, September 21, 2026

A plant population satisfies dydt=0.6y(1y900)\frac{dy}{dt}=0.6y\left(1-\frac{y}{900}\right). Which best describes the long-term limiting population?

Keep practicing AP Calculus BC

Question of the Day

Answer today's AP Calculus BC question, reveal the full explanation, then keep the streak going with a new question every day.

A plant population satisfies dydt=0.6y(1y900)\frac{dy}{dt}=0.6y\left(1-\frac{y}{900}\right). Which best describes the long-term limiting population?

  1. 0.60.6
  2. 900900 (correct answer)
  3. 540540
  4. 1/9001/900
  5. No limit; it grows without bound

Explanation: This question tests logistic model reasoning by describing the long-term population limit. The carrying capacity K=900K=900 is the value that yy approaches as tt increases, representing environmental sustainability. The inflection point at y=450y=450 indicates where growth peaks before decelerating toward KK. In logistic models, for positive initial yy, solutions converge to KK, not exceeding it indefinitely. A tempting distractor like choice E fails because growth is bounded by KK, not unbounded. A transferable strategy for logistic models is to extract KK from the equation as the long-term limit, applicable for predicting asymptotic behavior in population dynamics.