Saturday, December 3, 2011

An Oldie but a Goodie, The St Louis Arch


11-22-2011
Karl says:

A true masterpiece on several levels.

Did you know the shape is pure mathematics?  It is a catenary.
From Wikipedia, the free encyclopedia
A hanging chain forms a catenary.
The silk on a spider's web forming multiple (approximate) catenaries.
In physics and geometry, the catenary is the curve that an idealised hanging chain or cable assumes when supported at its ends and acted on only by its own weight. The curve is the graph of the hyperbolic cosine function, and has a U-like shape, superficially similar in appearance to a parabola (though mathematically quite different). Its surface of revolution, the catenoid, is a minimal surface and is the shape assumed by a soap film bounded by two parallel circular rings.

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