SARS: The following table shows the cumulative number of cases of SARS (severe acute respiratory syndrome) on selected days during the outbreak in 2003. Here t is time in days since the beginning of...

SARS: The following table shows the cumulative number of cases of SARS (severe acute respiratory syndrome) on selected days during the outbreak in 2003. Here t is time in days since the beginning of April, and N is the cumulative number of cases reported by time t

a. Approximate the value of dN dt at t = 19 using the average rate of change from t = 19 to t = 22.

b. Explain the meaning in practical terms of the number you calculated in part a.

c. Approximate the value of dN dt at t = 24 using the average rate of change from t = 24 to t = 29. What do you learn by comparing this result to the result in part a?