开中间立方体:最大化表面积的几何与函数演示
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该范例演示“在一个立方体中挖去/打开中间部分(开中间立方体)”时,如何通过变形与求解使剩余表面积达到最大。核心数学概念包括:立体几何的表面积分解、立方体/棱柱的面与棱的关联、几何差与交集带来的面积表达、以及用二次函数/幂函数刻画表面积随参数变化的最值问题(常与坡度/斜率的分析相联系)。作图要点是先用 GeoGebra 的 Point 与 Cube 构造基准立方体,再通过 Translate 产生移动后的点/结构以形成“开口”边界;随后使用 Intersect 计算交线/交点并用 Segment 连接关键点,得到各面区域(如 face1~face8 等)与对应边(edge1~edge7 等),最终把表面积表达映射到由参数控制的面片集合。适合中学竞赛或高中拓展学习,用于立体几何建模、几何—代数联系与最值优化思维训练,也可作为课堂演示或自主探究作业。
GeoGebra 命令及参数
Point(Circle[(1, 0), Distance[(0, 0), (1, 0)], Segment[(0, 0), (1, 0)]]) → ACube((0, 0), (1, 0), A) → a, B, faceABFE, faceCDEF, edge2, edge1, edge4, edgeAB, edge3, edgeBF, edgeCF, edgeCD, C, edge5, edgeDE, edgeAE, edgeEF, D, E, F, face1, face3, face2, face4Point(Circle[(2, 0), Distance[(1, 0), (2, 0)], Segment[(1, 0), (2, 0)]]) → GCube((1, 0), (2, 0), G) → b, H, faceGHLK, faceIJKL, edge7, edge6, edge9, edgeGH, edge8, edgeHL, edgeIL, edgeIJ, I, edge10, edgeJK, edgeGK, edgeKL, J, K, L, face5, face7, face6, face8Point(Circle[(3, 0), Distance[(2, 0), (3, 0)], Segment[(2, 0), (3, 0)]]) → MCube((2, 0), (3, 0), M) → c, N, faceMNRQ, faceOPQR, edge12, edge11, edge14, edgeMN, edge13, edgeNR, edgeOR, edgeOP, O, edge15, edgePQ, edgeMQ, edgeQR, P, Q, R, face9, face11, face10, face12Translate(a, Vector[(0, 0, 1)]) → a'Translate(c, Vector[(0, 0, 1)]) → c'Translate(c, Vector[(0, 0, 2)]) → c'_{1}Intersect(edge1, zAxis) → SPoint(Segment[(0, 0, 2), (0, -3, 2)]) → TPoint(Circle[T + (1, 0, 0), Distance[T, T + (1, 0, 0)], Segment[T, T + (1, 0, 0)]]) → UCube(T, T + (1, 0, 0), U) → e, V, face17, face18, edgeTV, edge16, edge17, edgeUV, edgeTW, edge20, edge21, edgeWZ, W, edge18, edge22, edge19, edge23, Z, A_1, B_1, face13, face15, face14, face16Point(Segment[(1, 0, 2), (1, -3, 2)]) → C_1Point(Circle[C_1 + (1, 0, 0), Distance[C_1, C_1 + (1, 0, 0)], Segment[C_1, C_1 + (1, 0, 0)]]) → D_1Cube(C_1, C_1 + (1, 0, 0), D_1) → f, E_1, face23, face24, edge25, edge24, edge27, edge29, edge26, edge31, edge33, edge32, F_1, edge28, edge34, edge30, edge35, G_1, H_1, I_1, face19, face21, face20, face22Point(Segment[(1, 0, 1), (1, -3, 1)]) → J_1Point(Circle[J_1 + (1, 0, 0), Distance[J_1, J_1 + (1, 0, 0)], Segment[J_1, J_1 + (1, 0, 0)]]) → K_1Cube(J_1, J_1 + (1, 0, 0), K_1) → g, L_1, face29, face30, edge37, edge36, edge39, edge41, edge38, edge43, edge45, edge44, M_1, edge40, edge46, edge42, edge47, N_1, O_1, P_1, face25, face27, face26, face28Point(Circle[(1, 1, 0), Distance[(0, 1, 0), (1, 1, 0)], Segment[(0, 1, 0), (1, 1, 0)]]) → Q_1Cube((0, 1, 0), (1, 1, 0), Q_1) → d, R_1, face35, face36, edge49, edge48, edge51, edge53, edge50, edge55, edge57, edge56, S_1, edge52, edge58, edge54, edge59, T_1, U_1, V_1, face31, face33, face32, face34Translate(d, Vector[(1, 0)]) → d'Translate(d, Vector[(2, 0)]) → d'_{1}Translate(d, Vector[(0, 1)]) → d'_{2}Translate(d, Vector[(1, 1)]) → d'_{3}Translate(d, Vector[(2, 1)]) → d'_{4}Translate(d, Vector[(0, 0, 1)]) → d'_{5}Translate(d, Vector[(0, 0, 2)]) → d'_{6}Translate(d, Vector[(1, 0, 1)]) → d'_{7}Translate(d, Vector[(2, 0, 1)]) → d'_{8}Translate(d, Vector[(2, 0, 2)]) → d'_{9}Translate(d, Vector[(1, 0, 2)]) → d'_{10}Translate(d, Vector[(0, 1, 1)]) → d'_{11}Translate(d, Vector[(0, 1, 2)]) → d'_{12}Translate(d, Vector[(1, 1, 1)]) → d'_{13}Translate(d, Vector[(1, 1, 2)]) → d'_{14}Translate(d, Vector[(2, 1, 1)]) → d'_{15}Translate(d, Vector[(2, 1, 2)]) → d'_{16}Segment(I, E) → hSegment((0, 0, 2), (0, 1, 2)) → iSegment((0, 1, 2), (0, 1, 3)) → jSegment((0, 1, 3), (1, 1, 3)) → kSegment((0, 1, 2), (1, 1, 2)) → lSegment((0, 0, 2), (1, 0, 2)) → mSegment((1, 1, 3), (2, 1, 3)) → nSegment((2, 0, 3), (2, 1, 3)) → pSegment((2, 0, 3), (2, 0, 2)) → qSegment((1, 1, 3), (1, 1, 2)) → rSegment((2, 1, 2), (1, 1, 2)) → sSegment((1, 0, 2), (1, 0, 1)) → tSegment((2, 0, 2), (2, 0, 1)) → f_1Segment((2, 0, 1), (2, 1, 1)) → g_1Segment((2, 1, 2), (2, 1, 1)) → h_1Segment((2, 1, 2), (2, 1, 3)) → i_1
AI 绘图提示语参考
画一个立方体,然后在其中心移除一部分,形成一个开放中间的立方体结构。展示移除部分后剩余表面的各个面和边,用线段连接边界点,并用不同颜色或样式区分各个面和边。先画出原始立方体,再画出移除部分,最后连接剩余部分的边界,形成开放中间的立方体,并可视化其表面结构。
以上提示语为根据原始绘图命令整理而来,仅供参考。