旋转多边形绕轴

旋转多边形绕轴
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2017-03-23 01:46
①本范例演示多边形绕轴旋转形成的三维图形与轨迹;②涉及核心数学概念包括多边形、三维向量、旋转变换、圆柱体表面形成;③作图要点运用了点、交点、多边形、旋转、笛卡尔曲线、曲面的GeoGebra命令;④适合高中立体几何、解析几何教学及空间想象能力培养。

GeoGebra 命令及参数

  1. Point(yAxis) → A
  2. Intersect(xAxis, yAxis) → B
  3. Point(xAxis) → C
  4. Polygon(A, B, C) → poly1, c, a, b
  5. Rotate(A, (-α), yAxis) → A'_1
  6. Rotate(B, (-α), yAxis) → B'_1
  7. Rotate(C, (-α), yAxis) → C_2
  8. Polygon(A'_1, B'_1, C_2) → poly1'_1, c'_1, a'_1, b'_1
  9. CurveCartesian(x(A) + (t * (x(C_2) - x(A))), y(A) + (t * (y(C_2) - y(A))), z(A) + (t * (z(C_2) - z(A))), t, 0, 1) → d
  10. CurveCartesian(x(B) + (t * (x(C_2) - x(B))), y(B) + (t * (y(C_2) - y(B))), z(B) + (t * (z(C_2) - z(B))), t, 0, 1) → e
  11. Surface((t * cos(u)), f(t), (t * sin(u)), t, 0, x(C), u, 0, α) → g
  12. Surface((t * cos(u)), 0, (t * sin(u)), t, 0, x(C), u, 0, α) → h