In Problems 1–12, a differential equation is given along with the field or problem a...

In Problems 1–12, a differential equation is given along with the field or problem area in which it arises. Classify each as an ordinary differential equation (ODE) or a partial differential equation (PDE), give the order, and indicate the independent and dependent variables. If the equation is an ordinary differential equation, indicate whether the equation is linear or nonlinear.

= kp (P - P), where k and P are constants

(logistic curve, epidemiology, economics)