"Sketch the region bounded by the curves , y = 8, x = 0, and find the volume of the solid generated by revolving the region about the y-axis."
I've sketched the region, and can visualise what they're looking for with the rotation thing, but I don't know how one actually calculates it...
I'd suspect integration is needed, but I'm not sure exactly what I'm supposed to be integrating...
Ok, I think the disks one seems simpler.. I'll go with it..
I see you're using pi r^2 and stacking the disks on top of one another, from 0 to 8 along the y-axis, that's fine - but where does the y^{4/3} come from? I presume it's something to do with the r^2... but I don't see where it comes from...