DPLL algorithm: Difference between revisions
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[[File:Quadrifolium.svg|thumb|Rotated Quadrifolium]] | |||
{{Dablink|This article is about a geometric shape. For the article about the plant, please see [[Four-leaf clover]]}} | |||
The '''quadrifolium''' | |||
(also known as '''four-leaved clover'''<ref> | |||
C G Gibson, ''Elementary Geometry of Algebraic Curves, An Undergraduate Introduction'', Cambridge University Press, Cambridge, 2001, ISBN 978-0-521-64641-3. Pages 92 and 93 | |||
</ref>) | |||
is a type of [[Rose (mathematics)|rose curve]] with n=2. It has [[polar equation]]: | |||
:<math>r = \cos(2\theta), \,</math> | |||
with corresponding algebraic equation | |||
:<math>(x^2+y^2)^3 = (x^2-y^2)^2. \,</math> | |||
Rotated by 45°, this becomes | |||
:<math>r = \sin(2\theta) \,</math> | |||
with corresponding algebraic equation | |||
:<math>(x^2+y^2)^3 = 4x^2y^2. \,</math> | |||
In either form, it is a [[algebraic curve|plane algebraic curve]] of [[geometric genus|genus]] zero. | |||
The [[dual curve]] to the quadrifolium is | |||
:<math>(x^2-y^2)^4 + 837(x^2+y^2)^2 + 108x^2y^2 = 16(x^2+7y^2)(y^2+7x^2)(x^2+y^2)+729(x^2+y^2). \,</math> | |||
[[File:Dualrose.png|thumb|Dual Quadrifolium]] | |||
The area inside the curve is <math>\tfrac 12 \pi</math>, which is exactly half of the area of the circumcircle of the quadrifolium. The length of the curve is ca. 9.6884.<ref>[http://mathworld.wolfram.com/Quadrifolium.html Quadrifolium - from Wolfram MathWorld]</ref> | |||
==Notes== | |||
<references /> | |||
==References== | |||
* {{cite book | author=J. Dennis Lawrence | title=A catalog of special plane curves | publisher=Dover Publications | year=1972 | isbn=0-486-60288-5 | page=175 }} | |||
==External links== | |||
* [http://jsxgraph.uni-bayreuth.de/wiki/index.php/Rose Interactive example with JSXGraph] | |||
[[Category:Sextic curves]] |
Revision as of 00:06, 2 September 2013
The quadrifolium (also known as four-leaved clover[1]) is a type of rose curve with n=2. It has polar equation:
with corresponding algebraic equation
Rotated by 45°, this becomes
with corresponding algebraic equation
In either form, it is a plane algebraic curve of genus zero.
The dual curve to the quadrifolium is
The area inside the curve is , which is exactly half of the area of the circumcircle of the quadrifolium. The length of the curve is ca. 9.6884.[2]
Notes
- ↑ C G Gibson, Elementary Geometry of Algebraic Curves, An Undergraduate Introduction, Cambridge University Press, Cambridge, 2001, ISBN 978-0-521-64641-3. Pages 92 and 93
- ↑ Quadrifolium - from Wolfram MathWorld
References
- 20 year-old Real Estate Agent Rusty from Saint-Paul, has hobbies and interests which includes monopoly, property developers in singapore and poker. Will soon undertake a contiki trip that may include going to the Lower Valley of the Omo.
My blog: http://www.primaboinca.com/view_profile.php?userid=5889534