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{{Uniform polyhedra db|Uniform polyhedron stat table|Girsid}} | |||
In [[geometry]], the '''great retrosnub icosidodecahedron''' is a [[nonconvex uniform polyhedron]], indexed as U<sub>74</sub>. It is given a [[Schläfli symbol]] s{3/2,5/3}. | |||
== Cartesian coordinates == | |||
[[Cartesian coordinates]] for the vertices of a great retrosnub icosidodecahedron are all the [[even permutation]]s of | |||
: (±2α, ±2, ±2β), | |||
: (±(α−βτ−1/τ), ±(α/τ+β−τ), ±(−ατ−β/τ−1)), | |||
: (±(ατ−β/τ+1), ±(−α−βτ+1/τ), ±(−α/τ+β+τ)), | |||
: (±(ατ−β/τ−1), ±(α+βτ+1/τ), ±(−α/τ+β−τ)) and | |||
: (±(α−βτ+1/τ), ±(−α/τ−β−τ), ±(−ατ−β/τ+1)), | |||
with an even number of plus signs, where | |||
: α = ξ−1/ξ | |||
and | |||
: β = −ξ/τ+1/τ<sup>2</sup>−1/(ξτ), | |||
where τ = (1+√5)/2 is the [[golden ratio|golden mean]] and | |||
ξ is the smaller positive real [[root of a function|root]] of ξ<sup>3</sup>−2ξ=−1/τ, namely | |||
: <math>\xi=\frac{\left(1+i \sqrt3\right)\left(\frac1{2 \tau}+\sqrt{\frac{\tau^{-2}}4-\frac8{27}}\right)^\frac13+ | |||
\left(1-i \sqrt3\right)\left(\frac1{2 \tau}-\sqrt{\frac{\tau^{-2}}4-\frac8{27}}\right)^\frac13}2</math> | |||
or approximately 0.3264046. | |||
Taking the [[odd permutation]]s of the above coordinates with an odd number of plus signs gives another form, the [[Chirality (mathematics)|enantiomorph]] of the other one. | |||
== See also == | |||
* [[List of uniform polyhedra]] | |||
* [[Great snub icosidodecahedron]] | |||
* [[Great inverted snub icosidodecahedron]] | |||
== External links == | |||
* {{mathworld | urlname = GreatRetrosnubIcosidodecahedron| title = Great retrosnub icosidodecahedron}} | |||
* http://gratrix.net/polyhedra/uniform/summary | |||
{{Polyhedron-stub}} | |||
[[Category:Uniform polyhedra]] |
Revision as of 23:48, 29 January 2014
Template:Uniform polyhedra db In geometry, the great retrosnub icosidodecahedron is a nonconvex uniform polyhedron, indexed as U74. It is given a Schläfli symbol s{3/2,5/3}.
Cartesian coordinates
Cartesian coordinates for the vertices of a great retrosnub icosidodecahedron are all the even permutations of
- (±2α, ±2, ±2β),
- (±(α−βτ−1/τ), ±(α/τ+β−τ), ±(−ατ−β/τ−1)),
- (±(ατ−β/τ+1), ±(−α−βτ+1/τ), ±(−α/τ+β+τ)),
- (±(ατ−β/τ−1), ±(α+βτ+1/τ), ±(−α/τ+β−τ)) and
- (±(α−βτ+1/τ), ±(−α/τ−β−τ), ±(−ατ−β/τ+1)),
with an even number of plus signs, where
- α = ξ−1/ξ
and
- β = −ξ/τ+1/τ2−1/(ξτ),
where τ = (1+√5)/2 is the golden mean and ξ is the smaller positive real root of ξ3−2ξ=−1/τ, namely
or approximately 0.3264046. Taking the odd permutations of the above coordinates with an odd number of plus signs gives another form, the enantiomorph of the other one.
See also
External links
- 22 year-old Systems Analyst Rave from Merrickville-Wolford, has lots of hobbies and interests including quick cars, property developers in singapore and baking. Always loves visiting spots like Historic Monuments Zone of Querétaro.
Here is my web site - cottagehillchurch.com - http://gratrix.net/polyhedra/uniform/summary