Solve each application of operations and composition of functions. Emis...

Solve each application of operations and composition of functions.

Emission of Pollutants When a thermal inversion layer is over a city, pollutants cannot rise vertically, but are trapped below the layer and must disperse horizontally. Assume that a factory smokestack begins emitting a pollutant at 8 a.m. and that the pollutant disperses horizontally over a circular area. Let t represent the time in hours since the factory began emitting pollutants (t = 0 represents 8 a.m.) and assume that the radius of the circle of pollution is

r(t) = 2t miles.

The area of a circle of radius r is represented by