For the equations (I) in Problem 8, what is the threshold value of S?

Data from in problem 8

Compare the diseases modeled by each of the follow- ing differential equations with the flu model in this sec- tion. Match each set of differential equations with one of the following statements. Write a system of differen- tial equations corresponding to each of the unmatched statements. (1) ds dt dI = -0.04.SI 0.04.SI -0.21 dt ds (III) = -0.03SI dt dI dt = 0.03.SI (II) ds dt dI dt = -0.002.SI = 0.002.SI - 0.31