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Path: utzoo!linus!faron!bs
From: bs@faron.UUCP (Robert D. Silverman)
Newsgroups: net.puzzle,net.math
Subject: Re: Polar Bear Problem Sequel
Message-ID: <376@faron.UUCP>
Date: Mon, 4-Nov-85 08:33:00 EST
Article-I.D.: faron.376
Posted: Mon Nov  4 08:33:00 1985
Date-Received: Tue, 5-Nov-85 21:16:40 EST
References: <855@whuxlm.UUCP> <593@hou2c.UUCP> <373@faron.UUCP>, <374@faron.UUCP> <327@mcgill-vision.UUCP>
Organization: The MITRE Coporation, Bedford, MA
Lines: 30
Xref: linus net.puzzle:1061 net.math:2114

> [ selected lines ]
> 
> > such that the radius of a great-circle running E-W is the same as that
> > of another great-circle running E-W which is 1 mile south. The only place
> > this happens is the great-circle 1/2 mile north of the equator. Moving
> > 1 mile south places you on the great-circle 1/2 mile south of the equator
> > Thus, of the entire set of great circles (cardinality C) only 1 satisfies
> > At latitude 90-theta, an East-West great circle has radius 2 PI r sin(theta)
> a great circle. This does not bring one back to the point where one started
> Then walking 1 mile north places one back on the original great circle, only
> 
>      Correct me if I'm wrong, but isn't a great circle a circle with its
> center at the center of the earth (yes, I know the earth isn't a sphere,
> but this discussion is pretending it is)?   Everyone  here  seems to  be
> using it to mean a circle of constant latitude.
> -- 
> 					der Mouse
> 
> {ihnp4,decvax,akgua,etc}!utcsri!mcgill-vision!mouse
> philabs!micomvax!musocs!mcgill-vision!mouse
> 
> Hacker: One responsible for destroying /
> Wizard: One responsible for recovering it afterward

Oops!!! Bad terminology. You are indeed correct. A great circle does in fact
have the center of the sphere as it's center. I should have said 'circle of
constant lattitude.' The math is right but the names were wrong. I typed
my response to the problem too quickly :-)

Bob Silverman   (they call me Mr. 9)