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In geometry, the great retrosnub icosidodecahedron or great inverted retrosnub icosidodecahedron is a nonconvex uniform polyhedron, indexed as U74. It is given a Schläfli symbol s. == 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. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Great retrosnub icosidodecahedron」の詳細全文を読む スポンサード リンク
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