The Rod is a flat transcendental curve defined by the equation (in the polar coordinate system):
Where - some constant constant.
It is a special case of the Archimedean spiral. at .
The calculation of the curvature of the spiral and the angle of inclination of the tangent are performed by the formulas:
The curve tends from infinity (where it asymptotically approaches the horizontal axis) to the point spinning around it in a spiral counterclockwise. The size of the spiral is determined by the coefficient . It has one inflection point - .
The curve refers to algebraic spirals .
The curve was named by the ancient Romans with a rod and described by Roger Cots in a collection of works entitled Harmonic Measurements (Harmonia Mensurarum) (1722), published 6 years after his death.
- Weisstein, Eric W. Lituus (English) on Wolfram MathWorld .