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Re:  Lune and lens: correct definitions?  Also in Wikipedia
Posted:
Jan 25, 2008 4:24 PM


JEMebius <jemebius@xs4all.nl> wrote:
> >> "David W.Cantrell" <DWCantrell@sigmaxi.net> writes: > >> > >>> The notion of a crescent or lune was discussed recently in > >>> alt.math.recreational. Interested readers might look at my second > >>> posting (Nov. 12) in the thread "crescent shapes" <http://groups.google.com/group/alt.math.recreational/msg/377799ffe126a44c> [snip] > Also take a look at http://en.wikipedia.org/wiki/Lune_%28mathematics%29
Thanks for the suggestion.
In my article in alt.math.recreational, to which I had provided a link, I had already given links to the Wikipedia entries for both lune and lens.
Their entry for lune says "In plane geometry, a lune is a concave area bounded by two arcs, necessarily of unequal radii." But I must suspect that that last condition originated with MathWorld. As such, I do not think it supports any necessity that the radii be unequal, but rather merely shows how "contagious" errors can be.
David



