Calculus
Consider the differential equation y′(x)=(y+2)(y−3).y^{\(\prime\)}(x)=(y+2)(y-3). In which regions are the solutions increasing?
Consider the differential equation x′(t)=x(x−2)(5−x)x^{\(\prime\)}(t)=x(x-2)(5-x). In which regions are the solutions decreasing?
A population of bacteria in a Petri dish is modeled by P′(t)+aP(t)=SP^{\(\prime\)}(t)+aP(t)=S, where P(t) P(t) is the population at time t t (in hours), a a is the death rate constant, and S S is the supply rate. If S=40 S = 40 cells per hour and a=0.2 a = 0.2 per hour, what is the equilibrium population?
Consider the differential equation y′(t)=sinyy^{\(\prime\)}(t)=\(\sin\) y for ∣y∣≤π2|y| ≤ \(\frac{π}{2}\). Which initial conditions y(0)=By(0) = B lead to solutions that are increasing in time?
Sketch a direction field for the following differential equation and the solution curve corresponding to the given initial condition. Assume t≥0t\(\ge\)0 and P≥0P\(\ge\)0.
P′(t)=0.02P(1−P1000)P^{\(\prime\)}(t)=0.02P\(\left\)(1-\(\tfrac{P}{1000}\]\right\)), P(0)=200P(0)=200