MATH 157 - D100A SSIGNMENT #8
Due date: Wednesday Mar 21, 2012
Instructor Questions accompanying paper Assignment # 8 Solution
Directions: Print double sided, write your solutions to both questions directly on this
page, place immediately after cover page and staple together!
Marks: An answer without a detailed solution process will be awarded zero marks!
Q1: The population of foxes (predators) in a certain region over a 2-year period is estimated to be
P(t) = 400 + 50sin 12
in month t, and the population of rabbits (prey) on the same region at time t is given by
P(t) = 3000 + 500cos ▯t :
Sketch the graphs of each of these two functions and explain the relationship between the sizes of
the two populations.
Solution: When the population of predators is maximum, its corresponds to the deepest decline of
the population of prey. When the population of predators is minimum, its corresponds to the steepest
increase of the population of prey.
DR. SHO, PRI2012