A.4.3.2 Smartphones

The function P gives the number of people, in millions, who own a smartphone, t years after year 2000. What does each equation tell us about smartphone ownership? a. P(17) = 2,320 b. P(-10) = 0

Use function notation to represent each statement. a. In 2010, the number of people who owned a smartphone was 296,600,000. b. In 2015, about 1.86 billion people owned a smartphone.

Mai is curious about the value of t in P(t) = 1,000. a. What would the value of t tell Mai about the situation? b. Is 4 a possible value of t here?

Here is a sketch of the graph with the information we have so far. It goes through four points: (-10, 0), (10, 296.6), (15, 1,860), and (17, 2,320).

The output of P is defined in terms of ‘millions of people’ instead of individual persons. What might be a reason for this?

The input is defined in ‘years after 2000.’ Could we have instead used calendar years, such as 2002?

What might be a reason to choose ‘years after 2000’ as the unit?