Go back to the starting time t $=0$ and to the initial values

S $=2,000,000,$ I$(0)=21,000,$ R$(0)=15,000.$

Recalculate the values of S$(2),$ I$(2),$ and R$(2)$ by using a time step of

t $=2.$ This only requires a single round of calculations, using S $0(0),$

I $0(0),$ and R $0(0).$ How do your answers compare to those computed in

part b$?$ Which estimates do you think are most accurate, those in part

b or those in part d$?$ Why?