Part 2
6.3: 3 Hint:
When no pesticide is used, the aphid population x(t) and the ladybug population y(t) are modeled by the predator-prey system:
dx/dt = ax - pxy
dy/dt = -by + qxy
The problem describes a pesticide which continuously kills the same proportion of both populations, where that proportion is given by f, a constant less than a. Therefore the new pesticide-added system is modeled by:
dx/dt = ax - pxy - fx
dy/dt = -by + qxy - fy