Chapter 4.1, Problem 59E

Credit Market Debt.

Since 2009, the annual rate of change in the national credit market debt can be modeled by the

function

$D^{\prime }\left(t\right)=33.428t+71.143$,

Where $D^{\prime }\left(t\right)$ is in billions of dollars per year and t is the number of years since 2009. (Source: Based on data from federalreserve.gov/release/g19/current.) Use the preceding information for Exercises 59 and 60.

Find the national credit market debt, $D\left(t\right)$, since 2009, given that

$D\left(0\right)=2555.229$

$D\left(t\right)=16.714t^2+71.143t+2555.229$