无字证明:摆线下的面积
几何画板及绘图内容加载中,请稍等……
该范例通过动态几何演示了摆线(旋轮线)一个拱形下方区域的面积等于其生成圆面积的三倍这一经典结论,属于“无字证明”类型。核心数学概念包括摆线的参数方程、定积分求面积、以及几何直观与代数推导的对应关系。作图要点:使用GeoGebra的CurveCartesian命令绘制摆线参数曲线,通过Point、Intersect、Polygon等构造关键点与多边形,利用Centroid、Vector、Circle、Segment、Midpoint、Mirror、Translate等工具进行面积分割与变换,配合滑块Animation实现动态展示,并辅以文本对象说明面积关系。适合高中至大学阶段的微积分、解析几何教学,也可用于数学科普演示,帮助学生直观理解积分几何意义。
GeoGebra 命令及参数
CurveCartesian((R * (i - sin(i))), (R * (1 - cos(i))), i, 0, Animation) → bPoint(b) → LIntersect(xAxis, yAxis) → OPolygon(D, B, O) → poly2, i, j, lCentroid(poly2) → MVector(M, J) → vCircle(M, If[Animation < 15, ((Animation - 10) * R / 5), R]) → hCircle(C, R) → cSegment(C, A) → dPolygon(D, E, O) → poly1, o, d_1, eSegment(D, B) → aMidpoint(a) → FMidpoint(O, B) → GMidpoint(B, E) → HCurveCartesian((R * (i - sin(i))), (R * (1 - cos(i))), i, 0, If[Animation < (2 * π), Animation, 6.283185307179586]) → fMirror(M, a) → M'Circle(M', If[Animation < 15, ((Animation - 10) * R / 5), R]) → gVector(M', I) → uTranslate(g, Vector[(If[Animation < 15, (-10 + Animation) / 5, 1] * u)]) → g'Circle(M', If[Animation < 15, ((Animation - 10) * R / 5), R]) → pTranslate(h, Vector[(If[Animation < 15, (-10 + Animation) / 5, 1] * v)]) → h'Translate(p, Vector[(If[Animation < 15, (-10 + Animation) / 5, 1] * u)]) → p'Circle(M, If[Animation < 15, ((Animation - 10) * R / 5), R]) → kTranslate(k, Vector[(If[Animation < 15, (-10 + Animation) / 5, 1] * v)]) → k'CurveCartesian((R * (i - sin(i))), (R * (1 - cos(i))), i, 0, If[Animation < (2 * π), Animation, 6.283185307179586]) → mPoint(m) → NVector(D, P) → wCircle(D, If[Animation < 15, ((Animation - 10) * R / 5), R]) → qTranslate(q, Vector[(If[Animation < 15, (-10 + Animation) / 5, 1] * w)]) → q'Circle(D, If[Animation < 15, ((Animation - 10) * R / 5), R]) → rTranslate(r, Vector[(If[Animation < 15, (-10 + Animation) / 5, 1] * w)]) → r'Point(p') → QSegment(I, Q) → nPoint(k') → SSegment(J, S) → sPoint(q') → TSegment(P, T) → a_1Midpoint(n) → UMidpoint(s) → VMidpoint(a_1) → WMidpoint(d) → ZCurveCartesian((R * (i - sin(i + π))), ((-R) * (1 - cos(i + π))) + (2 * R), i, (0 * R), If[Animation < (2 * π), Animation, 6.28319]) → zCurveCartesian((R * (i - sin(i + π))), ((-R) * (1 - cos(i + π))) + (2 * R), i, (0 * R), If[Animation < (2 * π), Animation, 6.28319]) → tCurveCartesian((R * (i - sin(i + π))), ((-R) * (1 - cos(i + π))) + (2 * R), i, (0 * R), If[Animation < π, Animation, 3.141592653589793]) → b_1Translate(q, Vector[(If[Animation < 15, (-10 + Animation) / 5, 1] * w)]) → q'_1
AI 绘图提示语参考
画一个动态的几何图形,展示一个摆线(旋轮线)下的面积等于其生成圆的三倍。首先绘制摆线,然后显示生成圆和摆线下的区域。通过动态滑块,展示摆线与圆的面积关系,并用几何方法分割和变换区域,最终证明面积关系。
以上提示语为根据原始绘图命令整理而来,仅供参考。