## Calculus: Early Transcendentals 8th Edition

a) $\frac{dP}{dt}$ represents the percentage rate of change per year. b) $\frac{dP}{dt}|_{t=2}$ represents the percentage rate of change in the city's electrical power after 2 years.
a) $\frac{dP}{dt}$ represents the percentage rate of change in the city's electricity power that is produced by solar panels since 2000. b) $\frac{dP}{dt}|_{t=2} = 3.5$ represents the percentage rate of change of the city's electrical power produced by solar panels in the year 2002.