棱锥体积猜想的动态演示(复制)
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① 本范例通过GeoGebra动态构造一个棱锥及其相关几何元素,直观演示棱锥体积与底面积、高之间的关系,并引导用户进行体积公式的猜想。② 核心数学概念包括棱锥体积公式(V = 1/3 × 底面积 × 高)、定积分在体积计算中的应用、算术平均与三角形/球体等几何体的关联,以及空间几何中的平移、旋转等变换。③ 作图要点:从构造摘要可见,使用了Sequence、Element、Point、Polygon、Segment、PointIn、Translate等命令,创建了多个点、多边形、线段和辅助对象(如z、w、v、a、O、P、α、β、sinα、cosα等),并利用滑块(echelle)控制缩放,通过平移构造棱锥的复制体(cube'),同时包含文本对象(texte1、texte2)用于显示公式或提示。④ 适合高中或大学低年级学生,用于立体几何教学、体积公式的探究性学习,也可作为微积分中定积分应用(如旋转体体积)的直观引入。
GeoGebra 命令及参数
Sequence(Mat * Element[cube, k], k, 1, 8) → cube'Element(Element[AE, 3], 1) → droiteSequence((Element[cube', k, 1, 1], Element[cube', k, 2, 1]), k, 1, 8) → listepointsPoint(listepoints) → APoint(listepoints) → EPoint(listepoints) → C_1Point(listepoints) → DPolygon(A, E, C_1, D) → poly1, a_1, b, c_1, dPoint(listepoints) → BPoint(listepoints) → FPoint(listepoints) → GPoint(listepoints) → HPolygon(B, F, G, H) → poly2, e, f, g, hPoint(listepoints) → CPolygon(F, C, A, B) → poly3, f_1, i, a_2, b_1Element(AB, 3, 1) → avantPolygon(C_1, G, H, E) → poly4, c_2, g_1, h_1, e_1Element(AC, 3, 1) → dessusPolygon(F, C, C_1, G) → poly5, f_2, c_3, c_4, g_2Polygon(A, B, H, E) → poly6, a_3, b_2, h_2, e_2Segment(E, A) → cSegment(A, C) → jSegment(A, B) → kSegment(C, C_1) → lSegment(C_1, E) → mSegment(H, E) → nSegment(A, B) → pSegment(B, H) → qSegment(H, E) → rSegment(H, G) → sSegment(B, F) → tSegment(G, C_1) → d_1Segment(F, G) → i_1Segment(F, C) → j_1PointIn(poly5) → JTranslate(J, Vector[val1 * Vector[A, B]]) → pyr1_1Translate(A, Vector[val1 * Vector[A, B]]) → pyr1_2Translate(B, Vector[val1 * Vector[A, B]]) → pyr1_3Translate(H, Vector[val1 * Vector[A, B]]) → pyr1_4Translate(E, Vector[val1 * Vector[A, B]]) → pyr1_5Polygon(pyr1_1, pyr1_2, pyr1_3) → poly11, pyr1_6, pyr1_7, pyr1_8Polygon(pyr1_1, pyr1_3, pyr1_4) → poly12, pyr1_9, pyr1_{10}, pyr1_{11}Polygon(pyr1_5, pyr1_1, pyr1_2) → poly13, pyr1_{12}, pyr1_{13}, pyr1_{14}Polygon(pyr1_5, pyr1_4, pyr1_3, pyr1_2) → poly14, pyr1_{15}, pyr1_{16}, pyr1_{17}, pyr1_{18}Translate(J, Vector[val2 * Vector[A, E]]) → pyr2_1Translate(E, Vector[val2 * Vector[A, E]]) → pyr2_2Translate(H, Vector[val2 * Vector[A, E]]) → pyr2_3Translate(C_1, Vector[val2 * Vector[A, E]]) → pyr2_4Translate(G, Vector[val2 * Vector[A, E]]) → pyr2_5Polygon(pyr2_1, pyr2_2, pyr2_3) → poly15, pyr2_6, pyr2_7, pyr2_8Polygon(pyr2_1, pyr2_4, pyr2_5) → poly16, pyr2_9, pyr2_{10}, pyr2_{11}Polygon(pyr2_1, pyr2_3, pyr2_5) → poly17, pyr2_{12}, pyr2_{13}, pyr2_{14}Polygon(pyr2_4, pyr2_2, pyr2_3, pyr2_5) → poly18, pyr2_{15}, pyr2_{16}, pyr2_{17}, pyr2_{18}Translate(J, Vector[val3 * Vector[D, A]]) → pyr3_1Translate(F, Vector[val3 * Vector[D, A]]) → pyr3_2Translate(B, Vector[val3 * Vector[D, A]]) → pyr3_3Translate(G, Vector[val3 * Vector[D, A]]) → pyr3_4Translate(H, Vector[val3 * Vector[D, A]]) → pyr3_5Polygon(pyr3_1, pyr3_3, pyr3_2) → poly19, pyr3_6, pyr3_7, pyr3_8Polygon(pyr3_2, pyr3_4, pyr3_5, pyr3_3) → poly20, pyr3_9, pyr3_{10}, pyr3_{11}, pyr3_{12}Polygon(pyr3_1, pyr3_2, pyr3_4) → poly21, pyr3_{13}, pyr3_{14}, pyr3_{15}Polygon(pyr3_1, pyr3_5, pyr3_4) → poly22, pyr3_{16}, pyr3_{17}, pyr3_{18}