min 4. A large spherical balloon is inflated at the rate of 18. When the radius is 2 feet, how fast is the radius changing?V= 5. All edges of a cube are expanding at the rate of 2 At the instant the edges are all 5 inches long find: sec a. the rate of change of the surface area of the cube. b. the rate of change of the volume of the cube. 6. A point is moving on the curve y=x so that the x-coordinate is changing at the rate of 3cmin When the y-coordinate is 25 centimeters, find the rate of change of the y-coordinate.