$\"\"$ number of US cellular phone subscribers (in millions) over the $\"\"$ years is shown in following table.

\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \

$\"\"$	$\"\"$	$\"\"$	$\"\"$	$\"\"$	$\"\"$	$\"\"$
$\"\"$	$\"\"$	$\"\"$	$\"\"$	$\"\"$	$\"\"$	$\"\"$

(a)

Average rate of cell phone growth:

Average rate of growth is defined as $\"\"$ .

Average rate of growth $\"\"$ .

(i)

From $\"\"$ to $\"\"$ :

Observe the table.

In the year $\"\"$ , the number of US phone subscribers are $\"\"$ .

Average rate of cell phone growth from $\"\"$ to $\"\"$ is $\"\"$ millions/year.

(ii)

From $\"\"$ to $\"\"$ :

Observe the table.

In the year $\"\"$ , the number of US phone subscribers are $\"\"$ .

Average rate of cell phone growth from $\"\"$ to 2004 is $\"\"$ millions/year..

(iii)

From $\"\"$ to $\"\"$ :

Observe the table.

In the year $\"\"$ , the number of US phone subscribers are $\"\"$ .

Average rate of cell phone growth from $\"\"$ to $\"\"$ is $\"\"$ millions/year..

(b)

Instantaneous rate of growth in 2002:

Consider the two average rates of change of (ii) and (iii) that is $\"\"$ and $\"\"$ .

Instantaneous rate of growth in $\"\"$ is determined by taking average of rates

Instantaneous rate of growth in $\"\"$ : $\"\"$ millions/year.

(c)

Instantaneous growth by measuring the slope of tangent:

$\"\"$

Slope of the tangent is $\"\"$ .

Observe the graph, $\"\"$ .

Instantaneous rate of growth in $\"\"$ is $\"\"$ million per year.

(a)

(i) Average rate of cell phone growth from $\"\"$ to $\"\"$ is $\"\"$ millions/year.

(ii) Average rate of cell phone growth from $\"\"$ to $\"\"$ is $\"\"$ millions/year.

(iii) Average rate of cell phone growth from $\"\"$ to $\"\"$ is $\"\"$ millions/year.

(b) Instantaneous rate of growth in $\"\"$ $\"\"$ millions/year.