等腰三角形与菱形的单位圆平移动画
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该范例展示了一个基于单位圆的动态几何动画,通过旋转、平移和缩放等变换,在圆内构造等腰三角形、四边形及菱形等图形,并观察它们随参数变化而运动的过程。核心数学概念包括等腰三角形的性质、菱形的判定、单位圆上的角度关系、向量的平移与缩放,以及几何变换的复合。作图要点使用了GeoGebra的Rotate(旋转)、Angle(角度)、Ray(射线)、Point(点)、Circle(圆)、Intersect(交点)、Segment(线段)、Line(直线)、LineBisector(中垂线)、CircleSector(扇形)、Dilate(缩放)、Vector(向量)、Translate(平移)、Midpoint(中点)、Polygon(多边形)等命令,涉及大量辅助对象如B_1、C、A'、α、f、g等。适合高中或大学低年级学生用于理解几何变换与动态构造,也可作为教师演示动画辅助教学。
GeoGebra 命令及参数
Rotate(B_1, 45°, C) → A'Angle(B_1, C, A') → αRay(C, A') → fRay(C, B_1) → gRotate(A', 45°, C) → A''Angle(A', C, A'') → βRay(C, A'') → hPoint(f) → ACircle(C, A) → cIntersect(c, h, 1) → DSegment(A, D) → iLine(A, g) → jIntersect(j, h) → ELineBisector(A, E) → kIntersect(k, g) → BSegment(A, B) → lSegment(B, E) → mCircle(C, m / 2) → dIntersect(d, h, 1) → FSegment(B, F) → nSegment(A, C) → pSegment(C, B) → qLine(C, F) → rCircle(C, 1) → eIntersect(e, r, 1) → GRay(C, G) → sCircle(E, (0.3 * Distance[E, D])) → tIntersect(t, j, 2) → HIntersect(t, h, 2) → ICircleSector(E, H, I) → c_1Segment(A, E) → aSegment(D, C) → bRotate(c_1, If[0 < o ≤ 1, ((-o) * π / 2), ((-π)) / 2], E) → d_1Dilate(E, If[1.5 < o ≤ 2.5, 2.5 - o, 0], C) → E'Vector(E, E') → uTranslate(d_1, u) → e_1Circle(C, Radius[t]) → f_1Intersect(f_1, p, 1) → JIntersect(f_1, q) → K,Dilate(C, If[2.5 < o ≤ 3.5, 3.5 - o, 0], A) → C'Rotate(D, If[2.5 < o ≤ 3.5, ((-(o - 2.5)) * π / 4), ((-π)) / 4], C) → D'Rotate(C, If[2.5 < o ≤ 3.5, ((-(o - 2.5)) * π / 4), ((-π)) / 4], C) → C'_1Segment(D', C'_1) → b'Intersect(f_1, b) → L,CircleSector(C, J, L) → g_1Rotate(g_1, If[4 < o ≤ 5, ((-(o - 4)) * π / 4), ((-π)) / 4], C) → h_1Segment(C, F) → i_1Segment(F, E) → j_1Segment(E, D) → k_1Dilate(C, If[5 < o ≤ 6, 6 - o, 0], F) → C'_2Segment(C, C'_2) → l_1Midpoint(B, E) → MDilate(B, If[6 < o ≤ 7, 7 - o, 0], M) → B'Segment(B, B') → m_1Dilate(M, If[7 < o ≤ 8, 8 - o, 0], E) → M'Segment(M, M') → n_1Line(M, j_1) → p_1Point(p_1) → NAngle(N, M, B) → γDilate(F, If[8 < o ≤ 9, 9 - o, 0], M) → F'Vector(F, F') → vTranslate(C, v) → C'_3Translate(C'_2, v) → OSegment(C'_3, O) → q_1Rotate(C'_3, If[9 < o ≤ 10, ((-(o - 9)) * (π - γ)), (-(π - γ))], M) → PRotate(O, If[9 < o ≤ 10, ((-(o - 9)) * (π - γ)), (-(π - γ))], M) → O'Segment(P, O') → r_1Rotate(P, If[10 < o ≤ 11, ((-(o - 10)) * π), (-π)], M) → P'Rotate(O', If[10 < o ≤ 11, ((-(o - 10)) * π), (-π)], M) → O''Segment(P', O'') → s_1Angle(A, B, E) → δRotate(P, If[11 < o ≤ 12, ((-(o - 11)) * δ), (-δ)], B) → P'_1Rotate(O', If[11 < o ≤ 12, ((-(o - 11)) * δ), (-δ)], B) → O''_1Segment(P'_1, O''_1) → t_1Rotate(P', If[11 < o ≤ 12, ((-(o - 11)) * δ), (-δ)], B) → P''Rotate(O'', If[11 < o ≤ 12, ((-(o - 11)) * δ), (-δ)], B) → O'''Segment(P'', O''') → a_1Dilate(A, If[12 < o ≤ 13, 13 - o, 0], D) → A'_1Segment(B, D) → f_2Circle(B, f_2 / 3) → c_2Intersect(c_2, f_2, 1) → QCircle(Q, f_2 / 3) → d_2Intersect(d_2, f_2, 2) → RDilate(B, If[13 < o ≤ 14, 14 - o, 0], Q) → B'_1Dilate(Q, If[14 < o ≤ 15, 15 - o, 0], R) → B'_2Dilate(R, If[15 < o ≤ 16, 16 - o, 0], D) → R'Segment(B, B'_1) → g_2Segment(Q, B'_2) → h_2Segment(R, R') → i_2Angle(D, B, C) → εRotate(C, If[16 < o ≤ 17, ((-(o - 16)) * ε), (-ε)], B) → C'_4Rotate(B, If[16 < o ≤ 17, ((-(o - 16)) * ε), (-ε)], B) → B'_3Segment(C'_4, B'_3) → q'Rotate(C'_4, If[17 < o ≤ 18, ((o - 17) * π), π], Q) → SRotate(B'_3, If[17 < o ≤ 18, ((o - 17) * π), π], Q) → TSegment(S, T) → q''Rotate(S, If[18 < o ≤ 19, ((o - 18) * π), π], R) → S'Rotate(T, If[18 < o ≤ 19, ((o - 18) * π), π], R) → T'Segment(S', T') → q'''Segment(B, F) → j_2Circle(B, q / 2) → e_2Intersect(e_2, j_2, 1) → UCircle(U, q / 2) → k_2Intersect(k_2, j_2, 2) → VDilate(B, If[19 < o ≤ 20, 20 - o, 0], U) → B'_4Dilate(U, If[20 < o ≤ 21, 21 - o, 0], V) → U'Dilate(V, If[21 < o ≤ 22, 22 - o, 0], F) → V'Dilate(F, If[19 < o ≤ 20, 20 - o, 0], V) → F'_1Dilate(V, If[20 < o ≤ 21, 21 - o, 0], U) → V'_1Dilate(U, If[21 < o ≤ 22, 22 - o, 0], B) → U'_1Segment(F, F'_1) → l_2Segment(V, V'_1) → m_2Segment(U, U'_1) → n_2Angle(F, B, C) → ζRotate(F, If[22 < o ≤ 23, ((o - 22) * π), π], V) → F'_2Rotate(F'_1, If[22 < o ≤ 23, ((o - 22) * π), π], V) → WSegment(F'_2, W) → p_2Rotate(F'_2, If[23 < o ≤ 24, ((o - 23) * π), π], U) → ZRotate(W, If[23 < o ≤ 24, ((o - 23) * π), π], U) → W'Segment(Z, W') → q_2Rotate(Z, If[24 < o ≤ 25, ((o - 24) * ζ), ζ], B) → Z'Rotate(W', If[24 < o ≤ 25, ((o - 24) * ζ), ζ], B) → W''Segment(Z', W'') → r_2Rotate(Z', If[25 < o ≤ 26, ((o - 25) * π), π], Z') → Z''Rotate(W'', If[25 < o ≤ 26, ((o - 25) * π), π], Z') → W'''Segment(Z'', W''') → s_2Polygon(A, D, C, B) → poly1, a_2, d_3, c_3, b_2Segment(A, D) → b_1