Here's the problem. I just have difficulty figuring out the problems where you are revolving a shape around something other than the x or y-axis. Any help would be greatly appreciated.
Here's the full problem:
Use the shell method to find the volume of the solid generated by revolving the plane region about the given line.
, , about the line
the nice thing with the shell method is that the only major change happens on the radius. recall that for dx-problems, the radius is right - left.
the distance from the y-axis to the object is x. and your axis of rotation is given. just figure out which is on the right.
here, if you draw a diagram, you will realize that the axis of rotation is on the right of the region you are revolving. the axis is 4, the region is at a distance x, so the radius is right - left = (axis of rot.) - (distance from y-axis) = 4 - x
now do the Shell method with that radius.