Question

Check: use disk method for solving

Answer 1

Mmk.

Answer 2

correct?

Answer 3

with pi being infront of course

Answer 4

Yes. Correct.

Answer 5

nah it's the wrong area i messed up should be

\[\int\limits_{0}^{2}y^6dy\]

Answer 6

Ummm I don't think so. y^6? How do you get that?

Answer 7

let me send a pic

Answer 8

Alright. You know how to attach it?

Answer 9

yes

Answer 10

Oh, okay. Your first answer was almost correct.
y from 0 to 2.
Outer radius is 8.
Inner radius is y^3.
Area of a disk cross-section is pi(8^2-(y^3)^2) = pi (8^2-y^6)

Answer 11

Oh. Um, why do you want that area? Does it say the area above the curve?

Answer 12

says find the volume of rotating it around the y axis using disk method. I'm wondering if it has to do with the area not being bounded.... if it said bounded by x=0 x=8 y=0 y=sqroot(x^3)

Answer 13

because if you bounded that area you'd get that sliver on hte right and you would have to do it method 2 or the right side

Answer 14

aka washer method

Answer 15

Riiight. Washer method.

Answer 16

You did both methods correctly it looks like. It's just a question of which area they want you to find. I'm not sure, since I don't know the wording of the question.

Answer 17

But since they say disk method, you're probably right that it's that upper area.

Answer 18

i think it's when you switch it to a funtion x=y^3... cause if you were to look at it as y=cube root of 3 it'd be the second

Answer 19

and that is how the question is phrasedd

Answer 20

Haha okay well the confusion isn't our fault. It's theirs. They didn't specify a bounded region, just a curve.

Answer 21

If you wanted to be a smartass, the actual correct answer would be to say that it has no volume.

Answer 22

Gosh I hate bad questions. C'mon teachers, get your ish together.

Answer 23

I Think i remember a question on this exam when i took it and i went up to him and said that it didn't make sense either

Answer 24

Yeah well. You're right that if it were the bottom region that they wanted they probably would have said washer method.

Answer 25

So the answer they want is probably that second one you gave. But the question is retarted.

Answer 26

I personally think he just took it out of the book and replaced it with different numbers only he didn't notice that they bound the area for you. This is what he probably based it off