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Topic: [ap-calculus] ellipsoid
Replies: 1   Last Post: May 25, 2012 10:26 AM

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Alan Lipp

Posts: 1,091
Registered: 12/6/04
RE: [ap-calculus] ellipsoid
Posted: May 25, 2012 10:26 AM
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Kevin,

Okay. I think you mean that if you rotate a semi-circle around its diameter you create a sphere, and the method of disks will give the volume of that sphere. If you rotate half an ellipse around one of its axes you produce an ellipsoid and the method of disks will give the volume of this ellipsoid. However, these are special cases. These produce ellipsoids one of whose cross-sections is a circle. The volume of these ellipsoids will be (4/3)pi a b^2 or (4/3) pi a^2 b. The general ellipsoid is not a soid of revolution.


Alan

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-----Original Message-----
From: Kevin Regardie [mailto:kregardie@sandi.net]
Sent: Friday, May 25, 2012 9:50 AM
To: AP Calculus
Subject: Re:[ap-calculus] ellipsoid

He's making the connection because when you integrate pi*r^2 using disk method you get volume so in turn he says the integral of pi*ab should give the volume of an ellipsoid. This is his reasoning. I appreciate the responses so far, but no one mentioned the INTEGRAL of area as it relates to volume. Thank you.
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