GoGeometry 第156题动态图解:四边形旋转与概率函数
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该范例动态演示了GoGeometry网站第156题,通过可拖拽的交互图形展示一般四边形在旋转、平移等变换下的几何关系,并关联概率与函数图像。核心数学概念包括一般四边形的性质、旋转变换、线段中点、角平分线、圆与圆弧、函数图像以及概率统计中的随机事件表示。作图要点基于GeoGebra命令:使用Rotate、Translate、Dilate等变换命令构造动态图形,通过Point、Segment、LineBisector、Intersect、Circle、Angle、Ray、Midpoint、Polygon、CircleSector、Vector等基础对象构建几何结构,并利用Min、Function Graph等命令生成函数曲线。适合高中及以上学段用于探究几何变换、动态几何与概率结合的综合问题,也可作为教师演示或学生自主探索的素材。
GeoGebra 命令及参数
Rotate(C, π / 3, A) → BSegment(B, C) → iPoint(i) → DLineBisector(A, D) → jLineBisector(D, B) → kIntersect(j, k) → C_1Circle(C_1, D) → dAngle(C, A, D) → αRotate(C, α / 2, A) → C'Ray(A, C') → lIntersect(d, l) → F_1, FRay(D, F) → mSegment(A, C) → nIntersect(m, n) → GMidpoint(G, C) → QDilate(A, If[0 < c ≤ 1, 1 - c, 0], C) → A'Segment(A, A') → fRotate(G, π / 3, F) → G'Ray(F, G') → j_1Intersect(f, j_1) → MMidpoint(F, M) → OMidpoint(O, M) → PPolygon(A, C, B) → t1, b', a, bRotate(C, If[1 < c ≤ 2, ((c - 1) * π / 3), π / 3], A) → B'_1Segment(A, B'_1) → gRotate(A, If[2 < c ≤ 3, ((c - 2) * π / 3), π / 3], B) → A'_1Segment(B, A'_1) → hAngle(C, A, C') → βIntersect(h, l) → EIntersect(d, n) → H, ICircle(A, (0.6 * Distance[A, I])) → eIntersect(e, n) → J,Dilate(C_1, If[6 < c ≤ 7, 7 - c, 0], B) → KCircle(C_1, K) → pSegment(C_1, K) → qSegment(A, F) → rDilate(A, If[8 < c ≤ 9, 9 - c, 0], D) → A'_2Segment(A, A'_2) → sRotate(J, If[9 < c ≤ 10, ((c - 9) * β), β], A) → J'Dilate(A, If[9 < c ≤ 10, 10 - c, 0], F) → A'_3Segment(A, A'_3) → tCircleSector(A, J, J') → c_1Dilate(F, If[10 < c ≤ 11, 11 - c, 0], E) → F'Segment(F, F') → f_1Rotate(c_1, If[11 < c ≤ 12, ((c - 11) * β), β], A) → d_1Dilate(D, If[12 < c ≤ 13, 13 - c, 0], F) → D'Segment(D, D') → g_1Dilate(F, If[13 < c ≤ 14, 14 - c, 0], G) → F'_1Segment(F, F'_1) → h_1Angle(B, F, A) → γAngle(G, F, E) → δRotate(A, If[15 < c ≤ 16, ((-(c - 15)) * γ), (-γ)], F) → A'_4Rotate(A'_3, If[15 < c ≤ 16, ((-(c - 15)) * γ), (-γ)], F) → LSegment(A'_4, L) → t'Rotate(F, If[16 < c ≤ 17, (((-(c - 16)) * 2) * π / 3), (-2 * π / 3)], F) → F'_2Rotate(F', If[16 < c ≤ 17, (((-(c - 16)) * 2) * π / 3), (-2 * π / 3)], F) → F''Segment(F'_2, F'') → i_1Angle(G, F, G') → εMin({Distance[E, C], Distance[G, C], f_1}) → oCircle(C, (0.6 * o)) → e_1Intersect(e_1, h, 1) → NRotate(N, If[17 < c ≤ 18, ((c - 17) * π / 3), π / 3], C) → N'Dilate(F, If[17 < c ≤ 18, 18 - c, 0], P) → F'_3CircleSector(C, N, N') → k_1Dilate(C, If[19 < c ≤ 20, 20 - c, 0], Q) → C'_1Segment(F, F'_3) → l_1Vector(C, C'_1) → uTranslate(k_1, u) → p_1Line(C, l_1) → m_1Point(m_1) → RAngle(A, C, R) → ζRotate(p_1, If[20 < c ≤ 21, ((c - 20) * ζ), ζ], Q) → q_1Dilate(Q, If[21 < c ≤ 22, 22 - c, 0], F) → Q'Vector(Q, Q') → vTranslate(q_1, v) → r_1Rotate(r_1, If[23 < c ≤ 24, ((c - 23) * π / 3), π / 3], F) → s_1