I'm also attempting another problem... A population has a periodic growth rate r(t) = A[1 + sin(t/(2*pi))], but otherwise follows the logistic population model with carrying capacity K. There is no threshold and the initial population is Yo = Y knot = K/2. a. Modify the basic logistic equation for this population. b. Use a change of variable z(t) = y/K to find a initial value equation in z(t). Then Solve for z(t). So far I have: Using the logistic growth equation: dy/dt = r(1-y/k)y Leading to: integral of [dy/((1-y/k)y)] = rt +c substituting for r: integral of [dy/((1-y/k)y)] = t*A[1 + sin(t/(2*pi))] + c I can't really follow how to use the change of variables well so part b is the most confusing part.