圆锥、圆柱与扇形的表面积相等关系(2D/3D动态演示)

圆锥、圆柱与扇形的表面积相等关系(2D/3D动态演示)
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2017-05-04 01:37
该范例通过二维与三维联动视图,直观演示圆锥、圆柱以及展开扇形三者表面积相等的几何关系。核心数学概念包括圆锥与圆柱的侧面积公式、扇形面积与弧长、以及立体图形的展开与表面积分解。作图要点:利用GeoGebra的Vector、Circle、Segment、Polygon、Cylinder、Angle、Cone、Circumference、Distance、PointIn、Plane、Rotate、CircleSector、CircleArc等命令,构建了可调节的圆锥与圆柱参数(如高度、半径),并通过动态对象(如滑块)控制尺寸,实时计算并比较表面积。适合高中或大学低年级学生学习立体几何、面积公式推导及动态数学建模,也可用于教师课堂演示或学生自主探索几何量之间的关系。

GeoGebra 命令及参数

  1. Vector(W_i, O) → diameter
  2. Vector(O, C_0) → r
  3. Circle(C_0, r_i, yAxis) → f
  4. Vector(H_i, O) → h_yAxisDown
  5. Vector(O, H_i) → h_YaxisUp
  6. Segment(O, H_i) → h_yAxis
  7. Vector(EdgeOfCylinder, W_i) → v_1
  8. Vector(W_i, EdgeOfCylinder) → h_edge
  9. Segment(H_i, EdgeOfCylinder) → d
  10. Vector(EdgeOfCylinder, H_i) → diameter_rev
  11. Vector(H_i, EdgeOfCylinder) → u_1
  12. Polygon(O, H_i, EdgeOfCylinder, W_i) → Two_dCylinderRep, TwoDCylinderRep_3, TwoDCylinderRep_2, TwoDCylinderRep_1, TwoDCylinderRep_4
  13. Segment(C_0, C_h) → TwoDCylinderRep_h
  14. Circle(C_h, r_i, yAxis) → g
  15. Cylinder((1 / 2 * w), (1 / 2 * w) + h, r_i) → Cylinder_1, c_i, c_h, CylinderSurface
  16. Vector(W_i, C_h) → s_1
  17. Angle(C_0, W_i, C_h) → b
  18. Vector(O, C_h) → s_2
  19. Segment(C_h, w) → s
  20. Angle(C_h, O, C_0) → b'
  21. Angle(O, C_h, w) → a
  22. Vector(C_0, C_h) → Height_cylinder
  23. Angle(C_h, C_0, O, xOyPlane) → c'
  24. Angle(C_h, C_0, W_i) → c
  25. Polygon(C_h, O, W_i) → Two_dConeFrameAsTriangle, Hypotenuse2_dMiniTriangleL, TwoDCylinderRep_0, o
  26. Cone(C_0, C_h, r_i) → Cone_i, c_iCone, ConeSurface
  27. Circumference(c_iCone) → pi_dCone
  28. Circle(circle_1, O, W_i) → circle_{2}Slice
  29. Circumference(circle_{2}Slice) → pi_dCircleEnd
  30. Distance(C_h, circle_1) → slant
  31. Segment(O, C_0) → radiusCone
  32. Circumference(circle_{2}Slice) → pi_dCircleEndSlice
  33. Circle(C_h, slant, xOyPlane) → t
  34. Circumference(t) → pi_dCircleT
  35. PointIn(t) → Pointt
  36. Segment(CutStart, C_h) → CompassLength
  37. Segment(C_h, CutStart) → cutFromLine
  38. Plane(circle_{2}Slice) → plane_Circle
  39. Rotate(CutStart, (-cutAngleMin), C_h) → CutFrom'
  40. Vector(C_h, CutStart) → v
  41. Vector(C_h, CutFrom') → v'
  42. CircleSector(C_h, CutStart, CutFrom', xOyPlane) → slice
  43. CircleArc(C_h, CutFrom', CutStart, xOyPlane) → ArcLengthDifferenceOfCircumferences
  44. Angle(CutFrom', C_h, CutStart) → θ
  45. CircleSector(C_h, CutFrom', CutStart, xOyPlane) → circle_2SliceInside
  46. Rotate(CutStart, (-ratio360deg), C_h) → CutDont
  47. CircleSector(C_h, CutDont, CutStart, xOyPlane) → e
  48. Angle(CutDont, C_h, CutStart, xOyPlane) → α