等角定理动态演示
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①本范例动态演示连接三角形顶点与外心的线段所形成的等角定理;②涉及核心数学概念包括等角定理、三角形外心、圆的性质;③作图要点提炼自构造摘要,使用了 Rotate(旋转)、Segment(线段)、LineBisector(角平分线)、Circle(圆)等 GeoGebra 命令/对象;④适合高中数学教学,用于理解三角形外心与等角定理的关联。
GeoGebra 命令及参数
Rotate(A, (-((a * π / 180))), B) → A'Angle(A', B, A) → αSegment(A, B) → fRay(B, A') → gPoint(g) → CSegment(A, C) → hSegment(B, C) → iLineBisector(i) → jLineBisector(f) → kIntersect(j, k) → DCircle(D, B) → cSegment(D, C) → lLine(A, B) → mOrthogonalLine(C, m) → nIntersect(m, n) → EMin({l, h, i}) → bCircle(C, (0.3 * b)) → dIntersect(d, h, 1) → FIntersect(d, l, 1) → GAngle(D, C, B) → βCircleSector(C, G, F) → eAngle(E, C, A) → γAngle(B, C, D) → δIntersect(d, i, 1) → HCircleSector(C, H, G) → pAngle(E, A, C) → εCircleSector(C, G, H) → qDilate(D, If[0 < o ≤ 1, 1 - o, 0], C) → D'Segment(D, D') → rRotate(C, If[1 < o ≤ 3, ((o - 1) * π), (2 * π)], D) → C'CircleArc(D, C, C') → sDilate(C, If[3 < o ≤ 4, 4 - o, 0], E) → C'_1Dilate(B, If[3 < o ≤ 4, 4 - o, 0], E) → B'Segment(B, B') → tSegment(C, C'_1) → f_1Angle(C, E, B) → ζCircleArc(C, G, F) → c_1Angle(F, C, G) → θRotate(e, If[5 < o ≤ 6, ((o - 5) * β), β], C) → e'Rotate(p, If[5 < o ≤ 6, ((-(o - 5)) * θ), (-θ)], C) → p'CircleArc(C, H, G) → d_1Point(f_1) → IMidpoint(A, B) → JSegment(A, E) → g_1Segment(A, J) → h_1Angle(I, C, H) → κRotate(q, If[5 < o ≤ 6, ((-(o - 5)) * κ), (-κ)], C) → q'CircleArc(C, G, H) → e_1CircleSector(C, F, G) → k_1Angle(G, C, H) → μRotate(k_1, If[5 < o ≤ 6, ((o - 5) * μ), μ], C) → p_1CircleArc(C, F, G) → q_1Polygon(A, B, C) → poly1, c_2, a_1, b_1Min(f, i) → uCircle(B, (0.2 * u)) → r_1Intersect(r_1, f) → K,Intersect(r_1, i) → L,CircleSector(B, L, K) → s_1