Chapter 5.2, Problem 80E

Telephone Service The percent $P$ of households in the United States with wireless-only telephone service from 2005 through 2014 can be approximated by the model

$\text{P = }-\text{3}\text{.42 + 1}\text{.297}t\text{ ln }t,\text{ 5}\le \text{t }\le \text{14 }$

where $t$ represents the year, with $t=5$ corresponding to $2005$.

(a) Approximate the percents of households with wireless-only telephone service in $2008$

and $2012$.

(b) Use a graphing utility to graph the function.

(c) Can the model be used to predict the percent of households with wireless-only telephone

service in $2020?$ in $2030?$ Explain.