正方形、切线与两相切圆
几何画板及绘图内容加载中,请稍等……
①本范例演示正方形、两相切圆及它们公共外切线的几何关系;②涉及核心数学概念包括圆、多边形、角、向量、函数、解析几何、几何作图等;③构造过程中运用了Circle(圆)、Segment(线段)、Intersect(交点)、Angle(角度)、Dilate(缩放)、Rotate(旋转)、Line(直线)、Midpoint(中点)、Polygon(多边形)、Vector(向量)、Translate(平移)等GeoGebra命令与对象;④适合高中阶段学生学习和理解几何构造与性质,可用于解析几何和几何作图的教学。
GeoGebra 命令及参数
Circle(A, D) → cCircle(B, F_2) → dSegment(H_1, G_1) → fCircle(G_1, f) → eCircle(H_1, f) → gIntersect(c, g, 1) → MIntersect(d, e, 2) → HAngle(M, H, G_1) → αAngle(H, G_1, E_2) → βAngle(G_1, H_1, M) → γAngle(H_1, M, H) → δSegment(M, H) → hSegment(H, G_1) → iSegment(M, H_1) → jDilate(A, If[0 < b ≤ 1, 1 - b, 0], D) → A'Segment(A, A') → lRotate(A, If[1 < b ≤ 2, ((b - 1) * π / 2), π / 2], A) → A'_1Rotate(A', If[1 < b ≤ 2, ((b - 1) * π / 2), π / 2], A) → A''Segment(A'_1, A'') → l'Rotate(A'_1, If[2 < b ≤ 3, ((b - 2) * π), π], C) → KRotate(A'', If[2 < b ≤ 3, ((b - 2) * π), π], C) → A'''Segment(K, A''') → l''Line(B, F_2) → mCircle(F_2, l / 5) → pIntersect(p, m) → L, M_1Circle(L, l / 5) → qIntersect(q, m) → N, OCircle(N, l / 5) → rIntersect(r, m) → P, QMidpoint(P, B) → RMidpoint(M, H) → SDilate(M, If[4 < b ≤ 5, 5 - b, 0], S) → I'Segment(M, I') → nDilate(S, If[5 < b ≤ 6, 6 - b, 0], H) → S'Segment(S, S') → sRotate(M, If[7 < b ≤ 8, ((b - 7) * π), π], S) → I'_1Rotate(I', If[7 < b ≤ 8, ((b - 7) * π), π], S) → I''Rotate(M, If[6 < b ≤ 7, ((b - 6) * π), π], S) → I'_2Rotate(I', If[6 < b ≤ 7, ((b - 6) * π), π], S) → I''_1Segment(I'_2, I''_1) → n'Rotate(M, If[7 < b ≤ 8, ((b - 7) * π / 2), π / 2], H) → GRotate(I', If[7 < b ≤ 8, ((b - 7) * π / 2), π / 2], H) → I''_2Segment(G, I''_2) → n'_1Rotate(I'_2, If[7 < b ≤ 8, ((b - 7) * π / 2), π / 2], H) → TRotate(I''_1, If[7 < b ≤ 8, ((b - 7) * π / 2), π / 2], H) → USegment(T, U) → n''Rotate(S, If[7 < b ≤ 8, ((b - 7) * π / 2), π / 2], H) → S'_1Angle(M, H, G_1) → εRotate(T, If[8 < b ≤ 9, ((b - 8) * π / 2), π / 2], G_1) → FRotate(U, If[8 < b ≤ 9, ((b - 8) * π / 2), π / 2], G_1) → U'Segment(F, U') → n'''Rotate(G, If[8 < b ≤ 9, ((b - 8) * π / 2), π / 2], G_1) → VRotate(I''_2, If[8 < b ≤ 9, ((b - 8) * π / 2), π / 2], G_1) → WSegment(V, W) → tRotate(S'_1, If[8 < b ≤ 9, ((b - 8) * π / 2), π / 2], G_1) → ZAngle(H, G_1, H_1) → ζRotate(F, If[9 < b ≤ 10, ((b - 9) * π / 2), π / 2], H_1) → T''Rotate(U', If[9 < b ≤ 10, ((b - 9) * π / 2), π / 2], H_1) → U''Segment(T'', U'') → f_1Rotate(Z, If[9 < b ≤ 10, ((b - 9) * π / 2), π / 2], H_1) → Z'Rotate(V, If[9 < b ≤ 10, ((b - 9) * π / 2), π / 2], H_1) → V'Rotate(W, If[9 < b ≤ 10, ((b - 9) * π / 2), π / 2], H_1) → W'Segment(V', W') → t'Polygon(H_1, G_1, H, M) → poly1, h_1, g_1, j_1, i_1Angle(G_1, H_1, M) → ηDilate(H_1, If[10 < b ≤ 11, 11 - b, 0], D) → H'Dilate(G_1, If[10 < b ≤ 11, 11 - b, 0], F_2) → ESegment(G_1, E) → k_1Segment(H_1, H') → l_1Angle(H_1, D, A) → θDilate(F_2, If[11 < b ≤ 12, 12 - b, 0], N) → F'Segment(F_2, F') → m_1Dilate(N, If[12 < b ≤ 13, 13 - b, 0], R) → N'Segment(N, N') → n_1Dilate(R, If[13 < b ≤ 14, 14 - b, 0], B) → R'Segment(R, R') → p_1Dilate(H, If[14 < b ≤ 15, 15 - b, 0], N) → J'Vector(H, J') → uTranslate(T, u) → T'_1Translate(U, u) → U'_1Segment(T'_1, U'_1) → n'''_1Translate(S'_1, u) → A_1Translate(G, u) → B_1Translate(I''_2, u) → C_1Segment(B_1, C_1) → q_1Dilate(H, If[15 < b ≤ 16, 16 - b, 0], R) → J'_1Vector(H, J'_1) → vTranslate(S'_1, v) → D_1Translate(T, v) → T'_2Translate(U, v) → U'_2Segment(T'_2, U'_2) → n'''_2Translate(G, v) → E_1Translate(I''_2, v) → F_1Segment(E_1, F_1) → r_1Dilate(H, If[16 < b ≤ 17, 17 - b, 0], B) → J'_2Vector(H, J'_2) → wTranslate(T, w) → T'_3Translate(U, w) → U'_3Segment(T'_3, U'_3) → n'''_3Angle(B, F_2, G) → ι