Q78 · Practice questionComplex unfamiliar7 marks
QUESTION 78 (7 marks)
A population satisfies
a)[3 marks]
Solve the differential equation for .
b)[2 marks]
Determine when , to two decimal places.
c)[2 marks]
Determine the population at which the instantaneous growth rate is greatest and the corresponding maximum growth rate.
WORKED SOLUTION
7 marksPractice marking scheme
ANSWER
(a) ; (b) ; (c) , rate .
Worked solution
(a) Separating and using partial fractions, Integrating gives . Using gives . Solving,
(b) For , , so and
(c) The growth rate is a concave quadratic with vertex . The maximum rate is population units per time unit.
Solves the logistic equation and uses the initial condition.
Determines the time.
Determines the population and maximum growth rate.
Practice question aligned to the current QCAA syllabus; review the worked solution and marking criteria.
View the QCAA syllabusHow many marks did you earn?
Compare your working with the guide above.