Well, our volume is going to be our area times the depth here. It's going to be that times the depth times dx. So the volume of this thing right over here, so the volume just of this coin, I guess you could call it, is going to be equal to my area times dx, which is equal to pi times x squared squared. So it's equal to pi x squared squared is x to the fourth. Pi x to the fourth dx. Now this expression right over here, this gave us the volume just of one of those disks, but what we want is the volume of this entire hat or this entire kind of bugle or cone-looking, or I guess you could say the front of a trumpet-looking thing. So how could we do that?