- #1
atomibay
- 3
- 0
Homework Statement
[itex]y = {\frac{1}{4+x^2}}[/itex] on the interval [0,2], revolving about y = -1
Use either the disk/washer or shell method to find the volume.
Homework Equations
[itex]v = pi\int (outer radius)^2-(inner radius)^2\,dx[/itex]
[itex]v = 2pi\int (radius)(height)\,dy[/itex]
[itex]
x = \sqrt{\frac{1}{y}-4}
[/itex]
The Attempt at a Solution
[itex]v = 2pi\int (y+1)
\sqrt{\frac{1}{y}-4}\,dy[/itex] from [itex]\frac{1}{4}[/itex] to [itex]\frac{1}{8}[/itex]
I'm just stuck on setting up the integral. I get confused easily from these washer/shell problems, and it's worse when the axis changes haha. So I don't know if this integral is set up correctly. And, I feel like there's something off about my limits. Do I have to add another integral to integrate from 0? Or would it just be easier to use the washer method?