Lituus (mathematics)
This article is about spiral. For Roman wand, see Lituus.
Branch for positive r
In mathematics, a lituus is a spiral with polar equation
where k is any non-zero constant. Thus, the angle θ is inversely proportional to the square of the radius r.
This spiral, which has two branches depending on the sign of , is asymptotic to the axis. Its points of inflexion are at and .
The curve was named for the ancient Roman lituus by Roger Cotes in a collection of papers entitled Harmonia Mensurarum (1722), which was published six years after his death.
External links
- Hazewinkel, Michiel, ed. (2001), "Lituus", Encyclopedia of Mathematics, Springer, ISBN 978-1-55608-010-4
- Weisstein, Eric W. "Lituus". MathWorld.
- Interactive example using JSXGraph
- O'Connor, John J.; Robertson, Edmund F., "Lituus", MacTutor History of Mathematics archive, University of St Andrews.
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