汤匙折叠的几何构造
几何画板及绘图内容加载中,请稍等……
①本范例演示了通过旋转和交点构造一个由汤匙折叠形成的几何图形;②涉及的核心数学概念包括分段函数、梯形、根、微积分和比例;③作图要点使用了PointIn, Segment, Point, Rotate, IntersectConic, Plane, Intersect, If, Polygon, Mirror, Distance, Circle, Ray等GeoGebra命令和对象;④适合高中及以上学生学习和理解复杂几何构造与微积分应用。
GeoGebra 命令及参数
PointIn(o) → ASegment(((-x(A)), y(A)), (x(A) - y(A) - 0.01, y(A))) → nnPoint(nn) → CSegment((Max[(-x(A)), x(Intersect[Circle[C, A], xAxis, 1])], 0), Intersect[Circle[C, A], xAxis, 2]) → jjPoint(jj) → BRotate(Polygon[{B, C, ((-x(A)), y(A)), ((-x(A)), 0)}], (pliage * π / 2), xAxis) → poly1Rotate(C, (pliage * π / 2), xAxis) → C'IntersectConic(Sphere[C', Distance[C, A]], Sphere[B, Distance[B, A]]) → cPlane(A, Plane[xAxis, zAxis]) → aIntersect(a, c) → D_1, D_2If(pliage ≟ 0, (x(A), y(A), 0), If[z(D_1) ≥ 0, D_1, D_2]) → DPolygon({B, C', D}) → poly2Polygon({B, D, Mirror[D, Plane[xAxis, zAxis]]}) → poly3Mirror(poly1, Plane[xAxis, zAxis]) → poly1'Mirror(poly2, Plane[xAxis, zAxis]) → poly2'Intersect(OrthogonalLine[B, Plane[C', D, Mirror[D, Plane[xAxis, zAxis]]]], Plane[C', D, Mirror[D, Plane[xAxis, zAxis]]]) → HSegment(B, H) → hPolygon({C', D, Mirror[D, Plane[xAxis, zAxis]]}) → poly4Polygon(A, ((-x(A)), y(A)), ((-x(A)), (-y(A))), (x(A), (-y(A)))) → poly5, a_1, f, g, iDistance(A, C) → distanceACCircle(C, A) → dSegment(B, (x(A), 0)) → kRay((x(D), 0, z(D)), (x(C'), 0, z(C'))) → lCircle(A, y(A)) → eSegment(B, A) → jSegment(B, C) → mMirror(B, xAxis) → B'Mirror(A, xAxis) → A'Segment(B', A') → j'Mirror(B, xAxis) → B'_1Mirror(C, xAxis) → C'_1Segment(B'_1, C'_1) → m'Segment(((-x(A)), 0), (x(A), 0)) → n