Earlier public high school enrollment: Here is a model for the number of students enrolled in U.S. public high schools as a function of time since 1965: In this formula N is the enrollment in millions...

Earlier public high school enrollment: Here is a model for the number of students enrolled in U.S. public high schools as a function of time since 1965:

In this formula N is the enrollment in millions of students, t is the time in years since 1965, and the model is applicable from 1965 to 1985.

a. Calculate N (7) and explain in practical terms what it means.

b. In what year was the enrollment the largest? What was the largest enrollment?

 c. Find the average yearly rate of change in enrollment from 1965 to 1985. Is the result misleading, considering your answer to part b?