螺旋转分立方体

螺旋转分立方体
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2018-12-08 03:53
①本范例演示了通过螺旋转动将立方体沿中位线对半分割的几何现象;②涉及的核心数学概念包括立体几何、旋转变换、中位线、二次函数及超几何分布;③作图要点——从下方『构造摘要』提炼用到了 Point(点)、Cube(立方体)、CurveCartesian(笛卡尔曲线)、Rotate(旋转)、Surface(曲面)、Translate(平移)、Polygon(多边形)等 GeoGebra 命令/对象;④适合高中及以上学段学习空间几何、变换及概率统计的学生,也可用于数学教学演示。

GeoGebra 命令及参数

  1. Point(Circle[B, Distance[A, B], Segment[A, B]]) → C
  2. Cube(A, B, C) → a, D, faceCDHG, faceEFGH, edgeAD, edgeAB, edgeBC, edgeCD, edgeAE, edgeDH, edgeEH, edgeEF, E, edgeBF, edgeFG, edgeCG, edgeGH, F, G, H, faceABCD, faceADHE, faceABFE, faceBCGF
  3. CurveCartesian(1, tan(t - π / 4), (4 * t / π), t, 0, π / 2) → e
  4. Rotate(e, π) → f
  5. Surface((u * cos(t - π / 4)), (u * sin(t - π / 4)), (4 * t / π), t, 0, π / 2, u, -2, 2) → b
  6. Surface((u * x(e(t))) + ((1 - u) * x(f(t))), (u * y(e(t))) + ((1 - u) * y(f(t))), (u * z(e(t))) + ((1 - u) * z(f(t))), t, 0, π / 2, u, 0, 1) → d
  7. Translate(Rotate[d, n, zAxis], Vector[(0, 0, (4 * n / π))]) → g
  8. Translate(Rotate[Polygon[E, F, G], n, zAxis], Vector[(0, 0, (4 * n / π))]) → t1
  9. Translate(Rotate[Polygon[D, A, B], n, zAxis], Vector[(0, 0, (4 * n / π))]) → t2
  10. Translate(Rotate[Polygon[A, B, F, E], n, zAxis], Vector[(0, 0, (4 * n / π))]) → q1
  11. Translate(Rotate[Surface[1, (-u) + ((1 - u) * y(e(t))), (2 * u) + ((1 - u) * z(e(t))), t, 0, π / 2, u, 0, 1], n, zAxis], Vector[(0, 0, (4 * n / π))]) → h
  12. Surface(-1, (-u) + ((1 - u) * y(f(t))), ((1 - u) * z(f(t))), t, 0, π / 2, u, 0, 1) → i
  13. Translate(Rotate[i, n, zAxis], Vector[(0, 0, (4 * n / π))]) → j
  14. Surface(1, (u * y(e(t))) + (1 - u), (u * z(e(t))), t, 0, π / 2, u, 0, 1) → k
  15. Surface(-1, (u * y(f(t))) + (1 - u), (u * z(f(t))) + ((1 - u) * 2), t, 0, π / 2, u, 0, 1) → l
  16. Polygon(E, H, G) → t3, g_1, e_1, h_1
  17. Polygon(B, C, D) → t4, d_1, b_1, c_1
  18. Polygon(C, D, H, G) → q2, c_2, d_2, h_2, g_2