This is the area to be rotated around the x-axis:
The graph of `y=x`, with the area under the "curve" between `x=0` to `x=2` shaded.
Hence, the volume generated can be found using the formula for volume of solid of revolution:
`"Vol" = pi int_a^b y^2 dx`
`=pi int_0^2 (x)^2 dx`
`=8/3 pi\ text[units]^3`