Let R be the region in the first quadrant bounded by the graph of y=x, the vertical line x = 9, and the x-axis, as shown in the figure. a) Write, then evaluate (show all of your work), an integral expression that gives the volume of the solid generated when R is rotated about the x-axis.
b) Write, then evaluate (show all of your work), an integral expression that gives the volume of the solid generated when R is rotated about the vertical line x = 9.