1. Disk/Washer and Shell

This isn't really a question about how to do a problem but more of a question about a set of rules.

Is there anyways i can find a set of rules for these methods? I am redoing homework to prepare for an exam on monday and i keep finding things that our teacher never told us i the homework, such as if you are rotating around an axis(for example y=10) that is above your area you need to do subtract the 10 from R(x). I am sure there are more unique rules than simply this. Any help is appreciated

2. Originally Posted by Juggalomike
This isn't really a question about how to do a problem but more of a question about a set of rules.

Is there anyways i can find a set of rules for these methods? I am redoing homework to prepare for an exam on monday and i keep finding things that our teacher never told us i the homework, such as if you are rotating around an axis(for example y=10) that is above your area you need to do subtract the 10 from R(x). I am sure there are more unique rules than simply this. Any help is appreciated
curve above y = 10 ... R(x) = f(x) - 10

curve below y = 10 ... R(x) = 10 - f(x)