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The volume of a cylinder of height `9` inches and radius `r` inches is given by the formula `V=9 pi r^2`.
Which is the correct expression for `(dV)/dt`?
Start by taking the derivative of the right hand side. We will apply the chain rule here. Note `pi` is just a number and can be viewed as a constant here.
Box 1: Select the best answer
`(dV)/dt=18 pi r (dr)/dt`