Answer to Question #50583 in Calculus for Aaqib Zaman

Question

The radius r (cm) of a circle at time t seconds is given by r = 9t - t^3 . At each of the following instants, find the rate of change of the radius (w.r.t.t) and state whether the radius is increasing or decreasing at these instants.
a) t =1 b) t =2 c) t =2.5