#59

[sxk1693]

Is there any tips on how to solve the volume of revolution problems. Do you guys just use the disk or washer method because that's how I learned how to do it. Or do you guys use the so called shell method.

I know the washer method is [unparseable or potentially dangerous latex formula].

This sometimes is hard to use when the line your supposed to revolve around is smack in the middle of the bounded region. I usually look at these questions for a minute or two and move on or I always get them wrong. Any tips.

[101dalmatians]

[007math]

The disk and washer method usually only works when you revolve around a line parallel to the x-axis. If you revolve around a line parallel to the y-axis, use the shell method (http://en.wikipedia.org/wiki/Shell_integration).

In my opinion, these problems are usually easy points since you just plug-n-chug. If you are spending 1-2 minutes on these problems, then I would suggest you to not look at them until you can get that time down to less than a minute.

I was going to attempt to teach shell method, but then I realized I don't know how to use [unparseable or potentially dangerous latex formula] with integrals and was too lazy to look it up.

EDIT: Just read Wikipedia and apparently you can use both methods to solve problems where axis of rotation is horizontal and vertical. Heh, didn't know that. But it would be a pain to rewrite equations in [unparseable or potentially dangerous latex formula] form.

[sxk1693]

[101dalmatians]