非传统弦与切线定理动态演示
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所属专题
Circles (Theorems)
①本范例动态演示了一个不常被提及的、同时关联弦与切线的定理。②涉及的核心数学概念包括圆、角、共线、旋转、相似等。③作图要点:运用了Circle(圆)、Point(点)、Tangent(切线)、Segment(线段)、Angle(角)、Rotate(旋转)、CircleArc(圆弧)、Intersect(交点)、CircleSector(扇形)、Dilate(缩放)、Ray(射线)、Distance(距离)等GeoGebra命令与对象。④适合高中及以上数学学习者,用于理解复杂几何定理的直观表现与证明思路。
GeoGebra 命令及参数
Circle(A_1, R) → cPoint(c) → BPoint(c) → ATangent(A, c) → j,Segment(A, B) → hAngle(B, A_1, A) → αRotate(B, α / 2, A_1) → D'CircleArc(A_1, A, B) → ePoint(e) → NTangent(N, c) → g,Intersect(g, j) → FSegment(D', F) → kIntersect(h, k) → PCircle(P, A) → p_2Intersect(p_2, h) → V, WSegment(A_1, R) → fCircleArc(A_1, B, A) → dAngle(B, A_1, D') → βTangent(B, c) → i,Intersect(g, i) → GSegment(D', G) → lIntersect(h, l) → QSegment(A, P) → mSegment(P, Q) → nSegment(Q, B) → pSegment(A_1, B) → qSegment(A_1, D') → rSegment(A_1, A) → sCircle(A_1, (0.2 * r)) → tIntersect(t, q, 1) → JIntersect(t, r, 1) → KCircleSector(A_1, J, K) → c_1Dilate(A_1, If[0 < b ≤ 1, 1 - b, 0], A) → A'Dilate(A_1, If[0 < b ≤ 1, 1 - b, 0], B) → J'Segment(A_1, J') → f_1Segment(A_1, A') → g_1Dilate(A_1, If[6 < b ≤ 7, 7 - b, 0], D') → A'_1Segment(A_1, A'_1) → h_1Circle(B, (0.2 * r)) → e_1Circle(A, (0.2 * r)) → k_1Intersect(k_1, j) → L, MIntersect(k_1, g_1) → N_1,Intersect(e_1, i) → O, P_1Intersect(e_1, f_1) → Q_1,CircleSector(A, N_1, M) → p_1CircleSector(B, O, Q_1) → q_1Rotate(q_1, If[1.5 < b ≤ 2.5, ((b - 1.5) * π / 2), π / 2], B) → s_1Dilate(A_1, If[3.5 < b ≤ 4.5, 4.5 - b, 0], N) → A'_2Segment(A_1, A'_2) → i_1Circle(N, (0.2 * r)) → t_1Intersect(t_1, g, 1) → R_1Intersect(t_1, i_1, 1) → SCircleSector(N, R_1, S) → c_2Dilate(N, If[2.5 < b ≤ 3.5, 3.5 - b, 0], G) → C'Dilate(N, If[2.5 < b ≤ 3.5, 3.5 - b, 0], F) → C'_1Segment(N, C') → j_1Segment(N, C'_1) → l_1Rotate(c_2, If[5 < b ≤ 6, ((b - 5) * π / 2), π / 2], N) → d_2Rotate(c_1, If[7.5 < b ≤ 8.5, ((b - 7.5) * β), β], A_1) → d_1Ray(B, O) → m_1Circle(G, 1) → e_2Intersect(e_2, i, 2) → TCircle(F, 1) → f_2Intersect(f_2, j, 1) → URay(A, M) → n_1Ray(F, U) → a_1Ray(G, T) → b_1Segment(B, G) → g_2Segment(A, F) → h_2Rotate(p_1, If[1.5 < b ≤ 2.5, ((-(b - 1.5)) * π / 2), ((-π)) / 2], A) → r_1Dilate(F, If[8.5 < b ≤ 9.5, 9.5 - b, 0], D') → D''Segment(D', D'') → i_2Dilate(G, If[9.5 < b ≤ 10.5, 10.5 - b, 0], D') → D''_1Segment(D', D''_1) → j_2Distance(D', P) → oDistance(D', F) → uDistance(D', Q) → wDistance(D', G) → o_1Dilate(A, If[10.5 < b ≤ 11.5, 11.5 - b, 0], P) → E'Segment(A, E') → k_2Dilate(P, If[11.5 < b ≤ 12.5, 12.5 - b, 0], W) → H'Segment(P, H') → l_2Dilate(Q, If[13.5 < b ≤ 14.5, 14.5 - b, 0], B) → I'Segment(Q, I') → m_2Dilate(W, If[12.5 < b ≤ 13.5, 13.5 - b, 0], Q) → W'Segment(W, W') → n_2Rotate(A, If[15 < b ≤ 16, ((b - 15) * π), π], P) → E'_1Rotate(E', If[15 < b ≤ 16, ((b - 15) * π), π], P) → E''Segment(E'_1, E'') → q_2Rotate(Q, If[16 < b ≤ 17, ((-(b - 16)) * π), (-π)], Q) → I'_1Rotate(I', If[16 < b ≤ 17, ((-(b - 16)) * π), (-π)], Q) → I''Segment(I'_1, I'') → r_2Segment(F, D'') → s_2Segment(G, D''_1) → t_2