You could rotate the part of the curve above y=2 around the line y=-1,
or the part of the curve between y=-1 and y=2.
Are you sure which one it is?
If you are rotating the top part above y=2,
you can rotate from x=0 to x=
and double, or rotate from x= to
Since the disc radii are
it's also possible to rotate above y=3 about the x-axis, if you are rotating the top section.
Do you have the full question?