阿基米德命题3动态演示
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这个范例动态演示了阿基米德《引理书》中命题3的图形。①它通过动态图形展示了命题中的几何关系;②涉及核心数学概念包括圆、直角三角形、角度、旋转和相似性;③作图要点使用了GeoGebra命令如半圆、线段、中点、垂线、交点、圆弧、点、角度、旋转、圆、缩放和线段;④适合高中数学教学,用于理解几何命题的证明和动态变化。
GeoGebra 命令及参数
Semicircle(A, B) → cLine(A, B) → fMidpoint(A, B) → COrthogonalLine(C, f) → gIntersect(c, g) → D,CircleArc(C, D, A) → dPoint(d) → EOrthogonalLine(E, f) → hIntersect(h, f) → FAngle(E, C, A) → βRotate(E, (-β), C) → E'Angle(E', C, E) → γCircle(F, A) → eIntersect(e, f, 2) → GSemicircle(A, B) → kAngle(A, F, E) → αDilate(A, If[0 < a ≤ 1, 1 - a, 0], F) → A'Segment(A, A') → iDilate(E, If[0 < a ≤ 1, 1 - a, 0], F) → E'_1Segment(E, E'_1) → jRotate(A, If[1 < a ≤ 2, ((-(a - 1)) * π), (-π)], F) → A'_1Rotate(A', If[1 < a ≤ 2, ((-(a - 1)) * π), (-π)], F) → A''Segment(A'_1, A'') → i'Rotate(A, If[2 < a ≤ 3, ((-(a - 2)) * β), (-β)], C) → A'_2CircleArc(C, A'_2, A) → pRotate(p, If[4 < a ≤ 5, ((-(a - 4)) * β), (-β)], C) → p'Rotate(E, If[4 < a ≤ 5, ((-(a - 4)) * β), (-β)], C) → E'_2Angle(E', B, A) → δDilate(A'_1, If[6 < a ≤ 7, 7 - a, 0], B) → HSegment(A'_1, H) → lRotate(A'_1, If[7.5 < a ≤ 8.5, ((-(a - 7.5)) * δ), (-δ)], B) → IRotate(H, If[7.5 < a ≤ 8.5, ((-(a - 7.5)) * δ), (-δ)], B) → H'Segment(I, H') → l'