MATHEMATICS · Single correct · AP · Calculus AB · Differentiation: Composite, Implicit, and Inverse Functions · Differentiation: Composite, Implicit, and Inverse Functions
Problem
For a spherical balloon, the radius r(t) is a differentiable function of time. At t=4 s, the balloon reaches a local maximum radius. Which of the following statements best describes the instantaneous rates of change of its volume V(t) and surface area A(t) at that instant?
(a) dtdV<0 and dtdA<0
(b) dtdV=0 but dtdA=0
(c) dtdV=0 and dtdA=0
(d) dtdV=0 while dtdA=0