We revisited 6.3.9, talked about how to do it using both the disk and the shell method. With section G, we discussed 6.1.15 (area between curves). With section C, we discussed 6.1.13 and 6.3.5. Remember that sometimes, one has to be careful about whether the region to rotate touches the x/y axis or not. This is why it is extremely useful to draw a picture.