catenary : exploration

CATENARY : Exploration

As we have seen, the Cartesian equation of the catenary is given by the hyperbolic cosine function which is the average of two exponential functions:

f(x) = cosh x = (ex + e –x)/2.

A more general form which allows for some scaling is f(x) = c cosh (x/c).

Although there are a couple of relationships with other standard curves (we shall look at these later), surprisingly the catenary appears to have no intrinsic properties of interest.



In 1744, Euler proved that the catenary is the curve which, when rotated, gives the surface of minimum surface area (the catenoid) for the given bounding circle.






Bibliography

A Book of Curves, Lockwood, E. H., (CUP 1967).

Wikipedia : http://en.wikipedia.org/wiki/Catenary

Wolfram MathWorld : http://mathworld.wolfram.com/Catenary.html