One of your company's salesmen estimates he will drive 20,000 miles this year and each of the next two years. As the service manager for the company's fleet of six-cylinder compact automobiles, you are asked to determine the total costs for each of the three years. Year 1 Total Cost: $ Year 2 Total Cost: $ Year 3 Total Cost:

Determine whether the following statements are true and give an explanation or counterexample. bold a. when using the shell method, the axis of the cylindrical shells is parallel to the axis of revolution. bold b. if a region is revolved about the y-axis, then the shell method must be used. bold c. if a region is revolved about the x-axis, then in principle it is possible to use the disk/washer method and integrate with respect to x or the shell method and integrate with respect to y.