This may be the wrong place to put it, but I'm having some problems:
Start with 200000 mosquitoes in a population which doubles every week. Predators eat 20000 mosquitoes a day. Model the population at any given time.
So... start with dP/dt=2P-140000P is population, t is in weeks.Seperation of variables gives me (after everything) something like P=70000+130000e^2t. The solution in the book is P=140000/ln2-ce^(ln(2)t), where c is the amount to bring it down to the initial population, something like 1900.
Obviously I'm missing a ln2 somewhere, but I can't locate it.
Start with 200000 mosquitoes in a population which doubles every week. Predators eat 20000 mosquitoes a day. Model the population at any given time.
So... start with dP/dt=2P-140000P is population, t is in weeks.Seperation of variables gives me (after everything) something like P=70000+130000e^2t. The solution in the book is P=140000/ln2-ce^(ln(2)t), where c is the amount to bring it down to the initial population, something like 1900.
Obviously I'm missing a ln2 somewhere, but I can't locate it.
