Chapter 9.2, Problem 52E

(a)

To determine

Whether the function, $f\left(t\right)=\frac{21.35t+69.59}{4.590t+233.1}$, is continuous for years from 2010 onwards, where t is the number of years after 2010.

(b)

To determine

To calculate: The value of the $\underset{x\to \infty }{\lim }f\left(t\right)$, and then find horizontal asymptote of $f\left(t\right)$.

(c)

To determine

The year where the model of the smart phone users is no longer valid.

(d)

To determine

Whether the limit, $\underset{t\to \infty }{\lim }f\left(t\right)$, gives the long-term projections of the fraction of smart phone users.