两内切圆与内接等边三角形的动态演示
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该范例展示了两个内切圆和一个内接等边三角形的动态关系。核心数学概念包括圆、等边三角形和几何变换。通过使用GeoGebra命令如Circle、Rotate、Intersect等,可以动态调整圆的大小和位置,观察等边三角形的变化。适合初中及以上学生学习几何变换和圆的相关性质。
GeoGebra 命令及参数
Circle(A, B) → cPoint(c) → DRotate(D, (2 * π / 3), A) → D'Rotate(D', (2 * π / 3), A) → D''CircleArc(A, D', D'') → sPoint(s) → CSegment(A, C) → gPoint(g) → FSemicircle(D'', F) → tSegment(F, C) → hCircle(F, h) → eIntersect(e, t, 1) → HSemicircle(D, F) → kIntersect(e, k, 1) → EDilate(D'', If[6 < b ≤ 7, 7 - b, 0], H) → D'''Segment(D'', D''') → k_1Line(E, k_1) → p_1Point(p_1) → LSemicircle(D', F) → pIntersect(e, p, 1) → GDilate(D', If[3 < b ≤ 4, 4 - b, 0], G) → D''_1Segment(D', D''_1) → f_1Line(D, f_1) → l_1Point(l_1) → SPolygon(D, D', D'') → t1, d'', d, d'Line(A, C) → fSegment(D, E) → iSegment(D', G) → jSemicircle(C, D'') → qSemicircle(D'', F) → rSegment(D'', H) → lCircle(D, j) → c_1Intersect(c_1, i) → I,Dilate(D, If[0 < b ≤ 1, 1 - b, 0], D') → D'_1Segment(D, D'_1) → mRotate(D, If[1 < b ≤ 2, ((b - 1) * π / 3), π / 3], D) → D'_2Rotate(D'_1, If[1 < b ≤ 2, ((b - 1) * π / 3), π / 3], D) → JSegment(D'_2, J) → m'Rotate(D'_2, If[2 < b ≤ 3, ((b - 2) * π / 3), π / 3], D'') → KRotate(J, If[2 < b ≤ 3, ((b - 2) * π / 3), π / 3], D'') → J'Segment(K, J') → m''Angle(D', G, F) → αAngle(D'', H, F) → βAngle(D, E, F) → γDilate(F, If[3 < b ≤ 4, 4 - b, 0], G) → F'Segment(F, F') → nDilate(D, If[4 < b ≤ 5, 5 - b, 0], I) → D'_3Segment(D, D'_3) → g_1Dilate(I, If[5 < b ≤ 6, 6 - b, 0], E) → I'Segment(I, I') → h_1Dilate(F, If[5 < b ≤ 6, 6 - b, 0], E) → F'_1Segment(F, F'_1) → i_1Dilate(F, If[6 < b ≤ 7, 7 - b, 0], H) → F'_2Segment(F, F'_2) → j_1Angle(S, D, E) → δDilate(G, If[8 < b ≤ 9, 9 - b, 0], D) → G'Vector(G, G') → uTranslate(D', u) → D''_2Translate(D''_1, u) → MSegment(D''_2, M) → m_1Rotate(D''_2, If[9 < b ≤ 10, ((b - 9) * δ), δ], D) → ORotate(M, If[9 < b ≤ 10, ((b - 9) * δ), δ], D) → M'Segment(O, M') → n_1Angle(L, E, D) → εDilate(H, If[10 < b ≤ 11, 11 - b, 0], E) → H'Vector(H, H') → vTranslate(D'', v) → D'''_1Translate(D''', v) → QSegment(D'''_1, Q) → q_1Rotate(D'''_1, If[11 < b ≤ 12, ((b - 11) * ε), ε], E) → RRotate(Q, If[11 < b ≤ 12, ((b - 11) * ε), ε], E) → Q'Segment(R, Q') → r_1