For 0 ≤ t ≤ 6 seconds, a screen saver on a computer screen shows two circles that start as dots and expand outwards. 1) At the instant that the first circle has a radius of 9 centimeters, the radius is increasing at a rate of 3/2 cm/sec. Find the rate at which the area of the circle is changing at that instant. 2)The radius of the first circle is modeled by g(t) = 12 - 12e-0.5t for 0 ≤ t ≤ where g(t) is measured in centimeters and t is measured in seconds. At what time t is the radius of the circle increasing at a rate of 3 cm/sec. 3) A model for the radius of the second circle given b the function f for 0 ≤ t ≤ 6, where f(t) is measured in cm and t is measured in seconds. The rate of change of the radius of the second circle is given by f1(t) = t2-4t+4. Based on this model, by how many cm is the radius of the second circle increasing from time t =0 to t = 3?