Worldwide cellular subscribers the millions of worldwide cellular subscribers can be modeled by
C(t) = 20.895t3 + 30.6t2 + 2.99t + 55.6
where t is the number of years past 1995.
(a) In what year does the model predict the number of worldwide cellular subscribers will reach a maximum?
(b) Do you think the number of worldwide cellular subscribers will decrease after the year found in part (a)?