Exponential Functions in Context

The value of some cell phones changes exponentially after initial release. Here are graphs showing the depreciation of two phones 1, 2, and 3 years after they were released.

What does the point (2, 360) of Phone A represent in this situation?

• Phone A is worth $2 after 360 years

• Phone A is worth $360 after 2 years

• Phone A has an initial amount of $360

• Phone A will be completely depreciated in value after 2 years.

The value of some cell phones changes exponentially after initial release. Here are graphs showing the depreciation of two phones 1, 2, and 3 years after they were released.

What is an appropriate domain for both functions?

The value of some cell phones changes exponentially after initial release. Here are graphs showing the depreciation of two phones 1, 2, and 3 years after they were released.

Complete the phrase:  Each year, as x, increases, the value of f(x) ______________. 

• Stays the same

• Decreases

• Increases

• None of these

The value of some cell phones changes exponentially after initial release. Here are graphs showing the depreciation of two phones 1, 2, and 3 years after they were released.

Which phone is more expensive to buy when it is first released? How do you know?

• Phone A because its initial cost is $1,000

• Phone B because its initial cost is $840

• They both cost the same in the beginning, $0

• Not enough information on the graph to know.

The function, f, gives the dollar value of a bond t years after the bond was purchased.  The graph of f is shown.

What is f(0)?  What does it mean in this situation?

• f(0) = 1500, the last bond value shown on the graph

• f(0) = 1000, how many years since purchased

• f(0) = 0, the initial purchase price of the bond

• f(0) = 1000, the initial value of the bond