Concept explainers
Cases of tuberculosis. The number of cases N of tuberculosis in the United States has decreased continually since 1956. In 1956, there were 69,895 cases. By 2012, this number had decreased by over 80%, to 10,521 cases.
a. Find the value of k, and write an exponential function that describes the number of tuberculosis cases after time t, where t is the number of years since 1956.
b. Estimate the number of cases in 2016 and in 2020.
c. At this decay rate, in what year will there be 5000 cases?
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Calculus and Its Applications (11th Edition)
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