Part A:

Assume that the height of your cylinder is 6 inches. Consider A as a function of r, so we

can write that as A(r)=2r2+12r. What is the domain of A(r)? In other words, for which values

of r is A(r) defined?

For a cylinder to exist the value of r > 0. Therefore the domain is (0, Infinity)

Part B:

Continue to assume that the height of your cylinder is 6 inches. Write the radius r as a

function of A. This is the inverse function to A(r), i.e to turn A as a function of r into. r as a

function of A.