The logarithmic spiral
Jacob Bernoulli of the famed mathematical clan from Switzerland was so
enamoured with the logarithmic spiral that he wanted it carved on his tomb in
Basle. The ‘Renaissance man’ Emanuel Swedenborg regarded the spiral as the
most perfect of shapes. A three-dimensional spiral which winds itself around a
cylinder is called a helix. Two of these – a double helix – form the basic structure
of DNA.
There are many classical curves, such as the limaçon, the lemniscate and the
various ovals. The cardioid derives its name from being shaped like a heart. The
catenary curve was the subject of research in the 18th century and it was
identified as the curve formed by a chain hanging between two points. The
parabola is the curve seen in a suspension bridge hanging between its two
vertical pylons.
marcin
(Marcin)
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