乌拉姆螺旋线
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这个范例演示了乌拉姆螺旋线的图形现象。核心数学概念包括质数分布和几何构造。作图要点:使用了 GeoGebra 命令 Join, Min, Sequence, Polygon, Length, Zip, RemoveUndefined;对象有 n, center, stepX, stepY, nn, listX, listY, scale, numsShow, factsShow, sprShow, A, B, C, back, D, mm, lp, prmsShow, text1, circles, spiral, pntShow, primes, numbers, cx, cy, prmsPoints, numsPoints。适合高中及以上学段的数学爱好者和研究人员。
GeoGebra 命令及参数
Join({{0, 1}, Join[Sequence[Join[{Sequence[0, j, 1, m], Sequence[(-1)^(m), j, 1, m + 1]}], m, 1, n]]}) → stepXJoin({{0, 0}, Join[Sequence[Join[{Sequence[(-1)^(m + 1), j, 1, m], Sequence[0, j, 1, m + 1]}], m, 1, n]]}) → stepYMin(Length[stepX], Length[stepY]) → nnSequence(Sum[stepX, m], m, 1, nn) → listXSequence(Sum[stepY, m], m, 1, nn) → listYPolygon((-1.2, -1.2), (1.2, -1.2), 4) → backLength(PrimeFactors[mm]) → lpZip(Circle[(2 * cx / n, 2 * cy / n), LP[center + k] / scale / n], cx, listX, cy, listY, k, Sequence[nn - 1]) → circlesSequence(mySegm[2 * (Element[listX, k], Element[listY, k]) / n, 2 * (Element[listX, k + 1], Element[listY, k + 1]) / n], k, 1, nn - 2) → spiralRemoveUndefined(Zip[If[LP[center + k] ≟ 1, Text[center + k, (2 * (cx - 0.15) / n, 2 * (cy - 0.05) / n)]], cx, listX, cy, listY, k, Sequence[nn - 1]]) → primesRemoveUndefined(Zip[Text[center + k, (2 * (cx - 0.15) / n, 2 * (cy - 0.05) / n)], cx, listX, cy, listY, k, Sequence[nn - 1]]) → numbersRemoveUndefined(Zip[If[LP[center + k] ≟ 1, 2 * (cx, cy) / n], cx, listX, cy, listY, k, Sequence[nn - 1]]) → prmsPointsZip(2 * (cx, cy) / n, cx, listX, cy, listY, k, Sequence[nn - 1]) → numsPoints