We estimate the rate at which the total personal income is rising in a city.
In 1999, the population of the city was 939,200, and increasing at 9500 per year.
The average annual income was $30,388 per capita, and increasing at $1300 per year.
Use the Product Rule and these figures to estimate the rate
at which total personal income was rising in the area in 1999.
Let = number of years since 1999.
After years, the population is: .
After years, the average income is: . dollars.
Hence, after years, the total income is: .
They are asking for
Differentiate using the Product Rule.
. . and simplify.