Modeling U.S. cellular subscriberships
The table shows the number of U.S. cellular subscriberships (in millions) from 1995 to 2008.
(a) Model these data with a power function S(x), where S is the number of U.S. cellular subscriberships (in millions) and x is the number of years past 1985.
(b) For the period from 1998 to 2008, use the data to find the average rate of change of U.S. cellular subscriberships.
(c) Find and interpret the instantaneous rate of change of the modeling function S(x) for the year 2008.