Question

Disposable income is the amount available for spending and saving after taxes have been paid and is one gauge for the state of the economy. Using U.S. Energy Administration data for selected years from 2010 and projected to 2040, the total U.S. disposable income, in billions, can be modeled by D(t) = 10,020e0.02292t where t is the number of years past 2010. In what year is disposable income predicted to be $17 trillion (that is, $17,000 billion)?

Answer 1

The disposable income predicted to be $17 trillion in 2033.

Explanation:

The disposable income, in billions, in t years after 2010 is given by the following function>

`D(t) = 10020e^(0.02292t)`

In what year is disposable income predicted to be $17 trillion (that is, $17,000 billion)?

This is t for which
`D(t) = 17000`. So

`D(t) = 10020e^(0.02292t)`

`17000 = 10020e^(0.02292t)`

`e^(0.02292t) = (17000)/(10020)`

`\ln{e^(0.02292t)} = \ln{(17000)/(10020)}`

`0.02292t = \ln{(17000)/(10020)}`

`t = \frac{\ln{(17000)/(10020)}}{0.02292}`

`t = 23`

2010 + 23 = 2033

The disposable income predicted to be $17 trillion in 2033.