The function P (t) = 21000+1800t computes the population of a city from years 1980-2001, with t=0 representing 1980. What is the domain and range in correct interval notation?

In year 2001, the corresponding value of t is 2001 - 1980 = 21. Thus the

domain is [0, 21]

The values of p (t) increase monotonically between those values of t, so the range of p (t) is p (0) = 21,000 to p (21) = 58,800.

range is [21000, 58800]