With U.S. Census Bureau data (actual and projected) for selected years from 1960 to 2050, the rate of change of U.S. population P can be modeled by dP / dt = - 0.0002187t2 + 0.0276t + 1.98 million people per year, where t0 represents 1960.
(a) In what year does this rate of change reach its maximum?
(b) In 1960, the U.S. population was 181 million. Use this to find a model for P(t).
(c) For 2025, the Census Bureau's predicted U.S. population is 348 million. What does the model predict?