List of spirals

This list of spirals includes named spirals that have been described mathematically.

Name	First described	Equation	Comment
circle		$r=k$	The trivial spiral
Archimedean spiral	c. 320 BC	$r=a+b\cdot \theta$
Euler spiral			also called Cornu spiral or polynomial spiral
Fermat's spiral (also parabolic spiral)	1636[1]	$r^{2}=a^{2}\theta$
hyperbolic spiral	1704	$r=a/\theta$	also reciprocal spiral
lituus	1722	$r^{2}\theta =k$
logarithmic spiral	1638[2]	$r=a\cdot e^{b\theta }$	approximations of this are found in nature
Fibonacci spiral		circular arcs connecting the opposite corners of squares in the Fibonacci tiling	approximation of the golden spiral
golden spiral		$r=\varphi ^{\theta {\frac {2}{\pi }}}\,$	special case of the logarithmic spiral
Spiral of Theodorus (also Pythagorean spiral)			an polygonal spiral composed of contiguous right triangles, that approximates the Archimedean spiral
involute	1673
helix		$r(t)=1,\,$ $\theta (t)=t,\,$ $h(t)=t.\,$	a 3-dimensional spiral
Rhumb line (also loxodrome)			type of spiral drawn on a sphere
Cotes's spiral	1722
Poinsot's spirals		$r=a\operatorname {csch} (n\theta ),\,$ $r=a\operatorname {sech} (n\theta )$
Nielsen's spiral	1993[3]	$x(t)=\operatorname {ci} (t),\,$ $y(t)=\operatorname {si} (t)$	A variation of Euler spiral, using sine integral and cosine integrals
Polygonal spiral			special case approximation of logarithmic spiral
Fraser's Spiral	1908		Optical illusion based on spirals
Conchospiral		${\begin{cases}r=\mu ^{t}a\\\theta =t\\z=\mu ^{t}c\end{cases}}$	three-dimensional spiral on the surface of a cone.
Calkin–Wilf spiral
Ulam spiral (also prime spiral)	1963
Sack's spiral	1994		variant of Ulam spiral and Archimedean spiral.
Seiffert's spiral			spiral curve on the surface of a sphere
Tractrix spiral	1704[4]	${\begin{cases}r=A\cos(t)\\\theta =\tan(t)-t\end{cases}}$
Pappus spiral	1779	${\begin{cases}r=a\theta \\\psi =k\end{cases}}$	3D conical spiral studied by Pappus and Pascal[5]
doppler spiral		${\begin{cases}x=a(t\cos(t)+kt)\\y=at\sin(t)\end{cases}}$	2D projection of Pappus spiral[6]
Atzema spiral		${\begin{cases}x=\sin(t)/t-2\cos(t)-t\sin(t)\\y=-\cos(t)/t-2\sin(t)+t\cos(t)\end{cases}}$	The curve that has a catacaustic forming a circle. Approximates the Archimedean spiral.[7]
Atomic spiral	2002	$r=\theta /(\theta -a)$	This spiral has two asymptotes; one is the circle of radius 1 and the other is the line $\theta =a$ [8]

References

"Fermat spiral - Encyclopedia of Mathematics". www.encyclopediaofmath.org. Retrieved 18 February 2019.
Weisstein, Eric W. "Logarithmic Spiral". mathworld.wolfram.com. Wolfram Research, Inc. Retrieved 18 February 2019.
Weisstein, Eric W. "Nielsen's Spiral". mathworld.wolfram.com. Wolfram Research, Inc. Retrieved 18 February 2019.
"Tractrix spiral". www.mathcurve.com. Retrieved 2019-02-23.
"Conical spiral of Pappus". www.mathcurve.com. Retrieved 28 February 2019.
"Doppler spiral". www.mathcurve.com. Retrieved 28 February 2019.
"Atzema spiral". www.2dcurves.com. Retrieved 11 March 2019.
"atom-spiral". www.2dcurves.com. Retrieved 11 March 2019.

This article is issued from Wikipedia. The text is licensed under Creative Commons - Attribution - Sharealike. Additional terms may apply for the media files.

[Fermat-1] "Fermat spiral - Encyclopedia of Mathematics". www.encyclopediaofmath.org. Retrieved 18 February 2019.

[Descartes-2] Weisstein, Eric W. "Logarithmic Spiral". mathworld.wolfram.com. Wolfram Research, Inc. Retrieved 18 February 2019.

[Nelsen-3] Weisstein, Eric W. "Nielsen's Spiral". mathworld.wolfram.com. Wolfram Research, Inc. Retrieved 18 February 2019.

[tractrix-4] "Tractrix spiral". www.mathcurve.com. Retrieved 2019-02-23.

[Pappus-5] "Conical spiral of Pappus". www.mathcurve.com. Retrieved 28 February 2019.

[doppler-6] "Doppler spiral". www.mathcurve.com. Retrieved 28 February 2019.

[Atzema-7] "Atzema spiral". www.2dcurves.com. Retrieved 11 March 2019.

[atomic-8] "atom-spiral". www.2dcurves.com. Retrieved 11 March 2019.

List of spirals

See also

References