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## Homework Statement

*Set up and evaluate an intergral to find the olume of a cone of height 12 m and radius 3 m at teh open end.*

A fast replay would be really helpful.

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In summary, you need to find the height of your chunk, and then use the standard formula for the geometric shape to set up the definite integral and evaluate it if necessary. A cross section of your cone looks like an isosceles triangle whose height is 12m and whose base is 6m. If you rotate this triangle around the y-axis, you get a cone.f

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A fast replay would be really helpful.

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What do you know about finding volumes of rotation? I would set up the integral (not intergral -- there is no such word) using disks.Hi. I need some help for a test tomoorow on thi sone kind of problem:

## Homework Statement

Set up and evaluate an intergral to find the olume of a cone of height 12 m and radius 3 m at teh open end.

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What do you know about finding volumes of rotation? I would set up the integral (not intergral -- there is no such word) using disks.

...um. I know how to do volumes or rotations, but this is a cone, not a line on a graph.

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You're still not makin gmuh sence.

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You can get the volume by using disks, where the radius of the disks decreases as you go from the bottom to the top.

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You can get the volume by using disks, where the radius of the disks decreases as you go from the bottom to the top.

I'm still not getting this. Can you work it out so I can see it?

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Here's an excerpt from the rules (https://www.physicsforums.com/showthread.php?t=5374).

On helping with questions: Any and all assistance given to homework assignments or textbook style exercises should be given only after the questioner has shown some effort in solving the problem. If no attempt is made then the questioner should be asked to provide one before any assistance is given. Under no circumstances should complete solutions be provided to a questioner, whether or not an attempt has been made.

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Here's an excerpt from the rules (https://www.physicsforums.com/showthread.php?t=5374).

On helping with questions: Any and all assistance given to homework assignments or textbook style exercises should be given only after the questioner has shown some effort in solving the problem. If no attempt is made then the questioner should be asked to provide one before any assistance is given. Under no circumstances should complete solutions be provided to a questioner, whether or not an attempt has been made.

so..you want me to look in a textbook that dosen;t explain how it got it's answer.

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Your textbook should have worked examples showing how to calculate volumes of revolution using both the disk method and the shell method.

My textbok doesn't really explain how to do it. It just does it.

And besides, I did try to do this problem for the last 45 minutes, and i got nowhere. Also, the books explanation in an exmple problem makes no sence...

EDIT: Figured it out, lock please.

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