阿基米德无限求和
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①本范例演示了阿基米德通过无限级数逼近圆面积的几何思想;②涉及核心数学概念包括级数求和、极限、连续性、上和与下和(黎曼和)、分段函数、几何变换、几何分布;③作图要点:使用 GeoGebra 的 Point, Intersect, Sequence, Polygon, Text 命令和对象,通过滑块 n 控制级数项数,动态展示逼近过程;④适合高中及以上学生及数学爱好者学习微积分和几何思想。
GeoGebra 命令及参数
Point(xAxis) → AIntersect(xAxis, yAxis) → BSequence(((2^(k) - 1) / 2^(k), (2^(k) - 1) / 2^(k)), k, 0, n_1 - 1, 1) → l1Polygon(B, A, 4) → poly1, f, g, h, i, C, DSequence((1, y(l1(k))), k, 1, n_1, 1) → l2Sequence(((2^(k) - 1) / 2^(k), (2^(k - 1) - 1) / 2^(k - 1)), k, 1, n_1, 1) → l4Sequence(Polygon[l1(k), l4(k), 4], k, 1, n_1 - 1, 1) → l5Sequence(Polygon[l1(k), l2(k), 4], k, 1, n_1 - 1, 1) → l3Sequence(Polygon[l4(k), l2(k), 4], k, 1, n_1 - 1, 1) → l6Sequence(Polygon[l1(k) + (0, 1 / 2^(k)), l4(k) + (0, 1 / 2^(k)), 4], k, 1, n_1 - 1, 1) → l7Text(Sum[Sequence[FractionText[l5(k)] + (If[k < n_1 - 1, "+", ""]) + (If[k ≟ 8, "+...", ""]), k, 1, n_1 - 1]], (1.03, 0.2), true, true) → text2Text(Sum[Sequence[FractionText[l5(k)] + (If[k < n_1 - 1, "+", ""]) + (If[k ≟ 8, "+...", ""]), k, 1, n_1 - 1]], (1.03, 0.35), true, true) → text1Text(Sum[Sequence[FractionText[l5(k)] + (If[k < n_1 - 1, "+", ""]) + (If[k ≟ 8, "+...", ""]), k, 1, n_1 - 1]], (1.03, 0.5), true, true) → text3