Question

What is the volume of the solid of revolution generated by revolving the area bounded by y = 2, y = x+3 and x = 4 around the x-axis

Answer 1

ahhh volume of solids :) nice

Answer 2

isnt that just a cone?

Answer 3

Lol - up for helping me out one more time?

Answer 4

spin this right?

Answer 5

it amounts to a cylinder and a cone :)

Answer 6

Yes, that's the same sketch I made

Answer 7

Lol

Answer 8

y = 2 when x = -1; -1 to 4 is 5 units;

area of the left part is 5(pi) 2^2

Answer 9

20 pi is the area of the "cylindar";

now add the cone...

Answer 10

we have a base area of pi 2^2 = 4pi; and a height from -1 to -3 = 2

Answer 11

4pi(2)
----- = 8pi/3 add the other
3

8pi + 60pi
--------- = 68pi/3
3

Answer 12

thats my guess :) cone plus cylinder = total;

Answer 13

this might be wrong but I have to leave

Answer 14

that might be right :)

Answer 15

hmm -

Answer 16

we can solve both ways ;)

Answer 17

you guys have fun i have a date lol

Answer 18

hmm - i'm not sure if 68pi/3 is right

Answer 19

we move everything to the right by 1 to get bounbes from 0 to 5; then rotate the triangle in a torus

Answer 20

It was a multiple choice question from the book - but no answer in the back to confirm

Answer 21

\[\pi \int\limits_{0}^{5} [f(x)]^2 dx\]

Answer 22

y=x+3 when moved to the right by 1 becomes:

y+1 = x+3

y = x+2

integrate (x+2)^2

Answer 23

(x+2)^3
------- = F(x); play with the 5 and we get... 343pi/3
3

Answer 24

the numerator seems to be off - it's either 14 pi, 275 pi or 140 pi

Answer 25

I can't seem to get any of those numbers on accident either!

Answer 26

lets see if I integrated it forrectly :)

u = x+2; du = dx

[S] u^2 du -> (u^3)/3 = (x+2)^3/3 thats right....

Answer 27

its from 0 to 5 so..... thats where I misssed it lol

pi(343-8)/3

Answer 28

i assumed 0 was just 0

Answer 29

we have to subtract something; the area of the cylindar beneath it.....

Answer 30

we made a solid and forgot to ...by we I mean me lol..... forgot to take away the solid formed beneath it

Answer 31

lol

Answer 32

subtract another 20pi

Answer 33

pi(343-68)/3

275pi/3

Answer 34

Great! Glad we (I mean you) could figure it out and explain it to me! Lol

Answer 35

lol.... i took the whole thing and forgot to cut out the center of the doughnot.... that was my error the first go araound

Answer 36

No worries!! I'm glad you could figure it out!

Answer 37

I appreciate the help very much! I may post a few more if you're still around!

Answer 38

this is the visual lol

Answer 39

i gotsta take a macroeconomics final so good luck ;)

Answer 40

Ahh! Haha

Answer 41

Good luck!