As the Baby Boom generation ages and the proportion of the U.S population over 65 increases, the

Question:

As the Baby Boom generation ages and the proportion of the U.S population over 65 increases, the number of Americans with Alzheimer's disease and other dementia is projected to grow each year. With data from the Social Security Administration and the Alzheimer's Association for selected years from 2000 and projected to 2050, the percent of the U.S. population with Alzheimer's can be modeled with the function

where t is the number of years past 1990.
(a) Find the function that gives the instantaneous rate of change of A(t).
(b) Use your answer in part (a) to find and interpret the instantaneous rate of change of the percent of the U.S. population with Alzheimer's in 2025.