Surface Area of a Sphere by Math Team - EnergyTech

Surface Area of a Sphere by Math Team - EnergyTech
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2018-09-20 13:39
This example demonstrates the calculation of a sphere's surface area. Key mathematical concepts include the geometric properties of a sphere and the surface area formula. Using GeoGebra commands such as Sphere, Rotate, and Segment, the generation process of the sphere and the changes in surface area can be dynamically displayed. Suitable for high school mathematics education and learning.

GeoGebra Commands & Parameters

  1. Line((0, 0, 1), (0, 1, 1)) → c
  2. Sequence(Rotate[(0, 0, 0), ((-((i * 15))))°, c], i, 0, 6) → list1
  3. Rotate(list1, 15°, zAxis) → list1'
  4. Line(Element[list1, 2], Element[list1', 2]) → l1
  5. Line((0, 0, 0), l1) → l0
  6. Sequence(Polygon[Element[list1, i], Element[list1', i], Element[list1', i + 1], Element[list1, i + 1]], i, 1, 6) → list2
  7. Segment(A, A + (0, 0, 1)) → a
  8. Point(a) → P
  9. If(z(P) ≥ 0.5, 0, (2 * (0.5 - z(P)))) → t
  10. If(z(P) ≥ 0.5, (2 * (1 - z(P))), 1) → s
  11. Translate(list2, Vector[(s * Vector[(0, 0, 0), (1, 0, 0)])]) → list2'
  12. Translate(l0, Vector[(s * Vector[(0, 0, 0), (1, 0, 0)])]) → l0'
  13. Sphere((0, 0, 1), 1) → b
  14. Sequence(Pyramid[Element[list2, i], (0, 0, 1)], i, 1, 6) → list3
  15. Translate(list3, Vector[(s * Vector[(0, 0, 0), (1, 0, 0)])]) → list3'
  16. Line(Element[list1, 3], Element[list1', 3]) → l2
  17. Line(Element[list1, 4], Element[list1', 4]) → l3
  18. Line(Element[list1, 5], Element[list1', 5]) → l4
  19. Line(Element[list1, 6], Element[list1', 6]) → l5
  20. Line(Element[list1, 7], Element[list1', 7]) → l6
  21. Rotate(Element[list3', 1], ((t * 7.5))°, l0') → d
  22. Translate(l1, Vector[(s * Vector[(0, 0, 0), (1, 0, 0)])]) → l1'
  23. Translate(l2, Vector[(s * Vector[(0, 0, 0), (1, 0, 0)])]) → l2'
  24. Translate(l3, Vector[(s * Vector[(0, 0, 0), (1, 0, 0)])]) → l3'
  25. Translate(l4, Vector[(s * Vector[(0, 0, 0), (1, 0, 0)])]) → l4'
  26. Rotate(l1', (7.5° * t), l0') → l1''
  27. Rotate(Rotate[Element[list3', 2], ((t * 7.5))°, l0'], ((t * 15))°, l1'') → e
  28. Rotate(Rotate[l2', ((t * 7.5))°, l0'], ((t * 15))°, l1'') → l2''
  29. Rotate(Rotate[Rotate[Element[list3', 3], ((t * 7.5))°, l0'], ((t * 15))°, l1''], ((t * 15))°, l2'') → f
  30. Rotate(Rotate[Rotate[l3', ((t * 7.5))°, l0'], ((t * 15))°, l1''], ((t * 15))°, l2'') → l3''
  31. Rotate(Rotate[Rotate[Rotate[Element[list3', 4], ((t * 7.5))°, l0'], ((t * 15))°, l1''], ((t * 15))°, l2''], (15° * t), l3'') → g
  32. Rotate(Rotate[Rotate[Rotate[l4', ((t * 7.5))°, l0'], ((t * 15))°, l1''], ((t * 15))°, l2''], ((t * 15))°, l3'') → l4''
  33. Rotate(Rotate[Rotate[Rotate[Rotate[Element[list3', 5], ((t * 7.5))°, l0'], ((t * 15))°, l1''], ((t * 15))°, l2''], (15° * t), l3''], (15° * t), l4'') → h
  34. Translate(l5, Vector[(s * Vector[(0, 0, 0), (1, 0, 0)])]) → l5'
  35. Rotate(Rotate[Rotate[Rotate[Rotate[l5', ((t * 7.5))°, l0'], ((t * 15))°, l1''], ((t * 15))°, l2''], ((t * 15))°, l3''], (15° * t), l4'') → l5''
  36. Rotate(Element[list2', 1], ((t * 7.5))°, l0') → poly1
  37. Rotate(Rotate[Rotate[Rotate[Rotate[Rotate[Element[list3', 6], ((t * 7.5))°, l0'], ((t * 15))°, l1''], ((t * 15))°, l2''], (15° * t), l3''], (15° * t), l4''], (15° * t), l5'') → i
  38. Rotate(Rotate[Element[list2', 2], ((t * 7.5))°, l0'], ((t * 15))°, l1'') → poly2
  39. Rotate(Rotate[Rotate[Element[list2', 3], ((t * 7.5))°, l0'], ((t * 15))°, l1''], ((t * 15))°, l2'') → poly3
  40. Rotate(Rotate[Rotate[Rotate[Element[list2', 4], ((t * 7.5))°, l0'], ((t * 15))°, l1''], ((t * 15))°, l2''], (15° * t), l3'') → poly4
  41. Rotate(Rotate[Rotate[Rotate[Rotate[Element[list2', 5], ((t * 7.5))°, l0'], ((t * 15))°, l1''], ((t * 15))°, l2''], (15° * t), l3''], (15° * t), l4'') → poly5
  42. Rotate(Rotate[Rotate[Rotate[Rotate[Rotate[Element[list2', 6], ((t * 7.5))°, l0'], ((t * 15))°, l1''], ((t * 15))°, l2''], (15° * t), l3''], (15° * t), l4''], (15° * t), l5'') → poly6
  43. OrthogonalPlane((0, 0, 1), zAxis) → m
  44. Translate(l6, Vector[(s * Vector[(0, 0, 0), (1, 0, 0)])]) → l6'
  45. Rotate(Rotate[Rotate[Rotate[Rotate[Rotate[l6', ((t * 7.5))°, l0'], ((t * 15))°, l1''], ((t * 15))°, l2''], ((t * 15))°, l3''], (15° * t), l4''], (15° * t), l5'') → l6''
  46. Rotate(Rotate[Rotate[Rotate[Rotate[Rotate[Rotate[m, ((t * 7.5))°, l0'], ((t * 15))°, l1''], ((t * 15))°, l2''], (15° * t), l3''], (15° * t), l4''], (15° * t), l5''], (7.5° * t), l6'') → n
  47. Mirror(i, n) → i'
  48. Mirror(h, n) → h'
  49. Mirror(g, n) → g'
  50. Mirror(f, n) → f'
  51. Mirror(e, n) → e'
  52. Mirror(d, n) → d'
  53. Mirror(poly6, n) → poly6'
  54. Mirror(poly5, n) → poly5'
  55. Mirror(poly4, n) → poly4'
  56. Mirror(poly3, n) → poly3'
  57. Mirror(poly2, n) → poly2'
  58. Mirror(poly1, n) → poly1'
  59. Sequence(Rotate[list3, 15° + ((15° * 22) * i), zAxis], i, 0, 1) → list4
  60. Mirror(list4, m) → list4'
  61. Sequence(Rotate[list2, (15° * i), zAxis], i, 1, 23) → list5
  62. Mirror(list5, m) → list5'