4.

4. [6 pts] The population of a city grows from an initial size of 10,000 to a size P, given by P(t) = 10,000 + 50t2, where t is in years. a. Use the definition of the derivative to find the growth rate, P' (t). b. Find the number of people in the city after 20 years. c. Find the growth rate after 20 years