Biomedical: Longevity and Exercise A study of the exercise habits of 17,000 Harvard alum...

Biomedical: Longevity and Exercise A study of the exercise habits of 17,000 Harvard alumni found that the death rate (deaths per 10,000 person-years) was approximately where x is the weekly amount of exercise in thousands of calories (0 ≤ x ≤ 4). Find the exercise level that minimizes the death rate.