The population of mosquitoes in a certain area increases at a
rate proportional to the current population, and in the absence of
other factors, the population doubles each week. There are 800,000
mosquitoes in the area initially, and predators (birds, bats, and
so forth) eat 60,000 mosquitoes/day. Determine the population of
mosquitoes in the area at any time. (Note that the variable t
represents days.)