等边三角形构建关系的动态演示
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①本范例动态演示了从任意三角形两边构建两个等边三角形时产生的特殊关系;②涉及核心数学概念包括全等、等边三角形、几何分布、对数、差值与斜率、三角函数;③作图要点:使用Segment、Rotate、Angle、Ray、Point、Polygon、Midpoint、Dilate等GeoGebra命令构建图形;④适合高中及以上数学学习者和教师用于探索几何变换与关系。
GeoGebra 命令及参数
Segment(A, B) → fRotate(B, (a * π / 180), A) → B'Angle(B, A, B') → αRay(A, B') → gPoint(g) → CSegment(B, C) → hSegment(A, C) → iPolygon(A, B, C) → poly1, c, a_1, bPolygon(C, B, 3) → poly2, j, k, l, DPolygon(A, C, 3) → poly3, m, n, p, ERotate(A, If[0 < d ≤ 1, (d * π / 3), π / 3], A) → A'Rotate(C, If[0 < d ≤ 1, (d * π / 3), π / 3], A) → C'Segment(A', C') → i'Rotate(B, If[0 < d ≤ 1, (d * π / 3), π / 3], C) → B'_1Rotate(C, If[0 < d ≤ 1, (d * π / 3), π / 3], C) → C'_1Segment(B'_1, C'_1) → h'Rotate(B'_1, If[1 < d ≤ 2, ((d - 1) * π / 3), π / 3], D) → IRotate(C'_1, If[1 < d ≤ 2, ((d - 1) * π / 3), π / 3], D) → JSegment(I, J) → h''Rotate(A', If[1 < d ≤ 2, ((d - 1) * π / 3), π / 3], E) → A''Rotate(C', If[1 < d ≤ 2, ((d - 1) * π / 3), π / 3], E) → C''Segment(A'', C'') → i''Midpoint(C, A) → FMidpoint(B, C) → GDilate(C, If[2 < d ≤ 3, 3 - d, 0], F) → C'_2Dilate(C, If[2 < d ≤ 3, 3 - d, 0], G) → C'_3Segment(C, C'_2) → qSegment(C, C'_3) → rRotate(C, If[3 < d ≤ 4, ((d - 3) * π), π], F) → C'_4Rotate(C'_2, If[3 < d ≤ 4, ((d - 3) * π), π], F) → HSegment(C'_4, H) → q'Rotate(C, If[3 < d ≤ 4, ((-(d - 3)) * π), (-π)], G) → C'_5Rotate(C'_3, If[3 < d ≤ 4, ((-(d - 3)) * π), (-π)], G) → KSegment(C'_5, K) → r'Midpoint(E, D) → LPolygon(F, G, L) → poly4, l_1, f_1, g_1Dilate(D, If[4 < d ≤ 5, 5 - d, 0], L) → D'Dilate(L, If[5 < d ≤ 6, 6 - d, 0], E) → L'Segment(D, D') → sSegment(L, L') → tRotate(D, If[6 < d ≤ 7, ((-(d - 6)) * π), (-π)], L) → D'_1Rotate(D', If[6 < d ≤ 7, ((-(d - 6)) * π), (-π)], L) → D''Segment(D'_1, D'') → s'Dilate(L, If[7 < d ≤ 8, 8 - d, 0], G) → L'_1Segment(L, L'_1) → eRotate(L, If[8 < d ≤ 9, ((d - 8) * π / 3), π / 3], G) → L'_2Rotate(L'_1, If[8 < d ≤ 9, ((d - 8) * π / 3), π / 3], G) → MSegment(L'_2, M) → e'Rotate(L'_2, If[9 < d ≤ 10, ((d - 9) * π / 3), π / 3], F) → NRotate(M, If[9 < d ≤ 10, ((d - 9) * π / 3), π / 3], F) → M'Segment(N, M') → e''