As baby boomers enter their golden years, the number of people afflicted with Alzheimer's disease is expected to rise dramatically. In a study published in the Journal of Neurology, the number of people with Alzheimer's disease in the United States age 65 years and over is projected to be

N(t) = 0.00525t2 + 0.075t + 4.7 (0 ? t ? 4)

(a) What is the projected number of people with Alzheimer's disease in the United States age 65 years and over in 2040? (Round your answer to four decimal places.)

(b) How fast is the number of people with Alzheimer's disease in the United States age 65 years and over projected to grow in 2040?

(c) How fast is the rate of growth of people with Alzheimer's disease in the United States age 65 years and over projected to change in the period covered by the study?