Question: OBESITY IN AMERICA The body mass index (BMI) measures body weight in relation to height. A BMI of 25 to 29.9 is considered overweight, a BMI of 30 or more is considered obese, and a BMI of 40 or more is morbidly obese. The percent of the U.S. population that is obese is approximated by the function
P(t) = 0.0004t3 + 0.0036t2 + 0.8t + 12 (0 ≤ t ≤ 13)
where t is measured in years, with t = 0 corresponding to the beginning of 1991. Show that the rate of the change of the percent of the U.S. population that is deemed obese was positive from 1991 to 2004. What does this mean?