Functions

1.) The number of cell phone accounts in a certain country has increased exponentially for the last decade. The nubmer of cell phone accounts (in millions) in this country can be approximated by the following function. Estimate the number of cell phone accounts in 2005.

 

f(x)=112.6e^.125x     (0≤ x≤ 9), where x=o corresponds to 2000.

 

What was the approximate number of cell phone accounts in 2005?

(round to the nearest thousand as needed.)

 

2.) The amount of plutonium remaining from 1 kilogram after x years is given by the function

                                                                 W(x)=2     -x/24,360

a.) How much will be left after 2000 years?

b.) How much will be left after 9000 years?

c.) How much will be left after 13,000 years?

d.) Estimate how long it will take for the 1 kilogram to decay to half it’s original weight.

(round the final answer to two decimal places as needed. Round all intermediate values to six decimal places as needed.)