# The number N of US cellular phone subscribers (in millions) is shown in the table. (Midyear...

## Question:

The number N of US cellular phone subscribers (in millions) is shown in the table. (Midyear estimates are given.)

Find the average rate of cell phone growth between the following years:

(a) from 1998 to 2004 (million phones/yr).

(b) from 2002 to 2004 (million phones/yr).

{eq}\begin{array}{|l|l|l|l|l|l|l|} \hline t & 1996 & 1998 & 2000 & 2002 & 2004 & 2006\\ \hline N & 44 & 69 & 109 & 141 & 182 & 233\\ \hline \end{array} {/eq}

## Average Rate of Change

One way that we can calculate the rate of change of a function is by finding the average rate of change. This finds the ratio of the change in the function over the change in the function's input.

$$\frac{f(b) - f(a)}{b-a}$$

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a) In order to find the average rate of change in cell phone subscribers from 1998 to 2004, we need to find the ratio of the change of subscribers...

Average Rate of Change: Definition, Formula & Examples

from

Chapter 20 / Lesson 5
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Finding the average rate of change is similar to finding the slope of a line. Study the definition of average rate of change, its formula, and examples of this concept.