(a) Write a single integral that gives the volume of the solid generated when R is revolved about the :raxis.(Do not evaluate the integral). If using the disk/washer method, make sure to clearly indicate inner and outer radii by labeling them (for a generic disk/ washer) and expressing formulas for them. If using the shell method, make sure to clearly indicate radius and height by labeling them (for a generic shell) and expressing formulas for them. (b) Briey describe Why you chose the method you did for part (a) and Why the \"other\" method wouldn't have resulted in a single integral. How did you determine the variable of integration