Pretest Exponential Functions

Which does y=.5(2)^x represent?

• Exponential Growth

• Exponential Decay

Which variable represents time passed in the function y=ab^x?

• y

• a

• b

• x

What is the asymptote of the parent function y=2^x?

• x=0

• y=0

• x=2

• y=2

Bacteria growing can be represented by which of the following?

• Exponential Growth

• Exponential Decay

Is the following function and example of decay or growth?

f(x)=2(0.85)^x

• Exponential Decay

• Exponential Growth

Is the following function an example of decay or growth? f(x) = 2(1.25)^x

• Exponential Growth

• Exponential Decay

A new savings account is opened with $400 and gains 3% every year. What is the exponential function?

• f(x)=400(1+3)^x

• f(x)=400(1-0.03)^x

• f(x)=400(1+0.03)^x

• f(x)=400(0.03)^x

The amount of ants in a colony, f, that is decaying can be modeled by                      f(x) = 800(.87)^x, where x is the number of days since the decay started. By what percentage is the colony decaying?

• 87%

• 13%

• 800%

• 8.7%

The amount of ants in a colony, f, that is decaying can be modeled by                         f(x) = 800(.87)^x, where x is the number of days since the decay started. Suppose           f(20) = 49. Which of the following is true?

• After 20 days, there are 49 ants in the colony.

• After 49 days there are 20 ants in the colony.

• The amount of ants times 20 is 49.

• After 20 days the amount of ants remaining decreases by 49.

The amount of downloads for an album on iTunes, g(d), where d is the number of days since the album was first uploaded can be represented as
g(d) = 5^1.5d
How many downloads will the album have after 3 days?

• 125

• 11

• 1398

• 140