Well, the problem didn't specify anything like that. All I received was the equation, the interval and what axis it's rotating about, so I just presumed that's what the graph would look like for the problem.
I'll try working it out with inner radius as 0 though, thanks!
Yeah, I've tried graphing it but even while I was looking at it, I'm still confused as to how to read the inner radius and the outer radius.
I figured that the inner radius is (y+1) and the outer is \frac{1}{4+x^2}, right?
I'm not sure about the area though.
Homework Statement
y = {\frac{1}{4+x^2}} on the interval [0,2], revolving about y = -1
Use either the disk/washer or shell method to find the volume.
Homework Equations
v = pi\int (outer radius)^2-(inner radius)^2\,dx
v = 2pi\int (radius)(height)\,dy
x = \sqrt{\frac{1}{y}-4}...