等距变换案例4:独立平移与镜像(R&T)
几何画板及绘图内容加载中,请稍等……
该范例展示在给定几何配置下,通过“平移 + 镜像(Rotation/Reflection & Translation 的组合思路,此处以 R&T 表示)”实现等距对应,并在连续变换后保持边长与周长关系。核心数学概念包括:等距变换(保距/保角)、向量表示的平移、关于直线的镜像、对应点(preimage 与像点)与多边形的面积/周长不变量,以及由相似三角形与比例关系推导出的量的一致性。作图要点:利用 If、Vector、Translate、Line、Mirror、Point、Polygon 等 GeoGebra 命令构造基本几何元素;用 Line 与 lineOfReflection 指定镜像轴;用 Translate 结合 GRVector 进行平移得到像点(如 A'、B' 等的成对对象);用 Mirror 将平移后的结果进一步映射(得到 A''、B'' 等);通过 Animator/anim1/anim2 与中间量 interimRT、a'3 等实现分步动画;以 Polygon 连接点形成多边形/立体投影轮廓,并观察与周长、比值相关的保持现象。适合中学竞赛或高中几何拓展课程,用于讲解“等距变换如何生成对应图形”以及“相似与比例在变换下的一致性”。
GeoGebra 命令及参数
If(animator > 1, animator - 1, 0) → anim2Vector(K, L) → GRVectorTranslate(A, GRVector) → A'Line(I, J) → lineOfReflectionMirror(A', lineOfReflection) → A''If(animator > 1, 1, animator) → anim1Point(Circle[A, 1.2851459061133876]) → BPolygon(A, B, C, D, E, F) → preimage, a, b, c, d, e, fMirror(A, lineOfReflection) → A'_{1}Mirror(B, lineOfReflection) → B'_{1}Mirror(C, lineOfReflection) → C'_{1}Mirror(D, lineOfReflection) → D'_{1}Mirror(E, lineOfReflection) → E'_{1}Mirror(F, lineOfReflection) → F'_{1}Mirror(A, lineOfReflection) → A'_{3}Mirror(B, lineOfReflection) → B'_{3}Mirror(C, lineOfReflection) → C'_{3}Mirror(D, lineOfReflection) → D'_{3}Mirror(E, lineOfReflection) → E'_{3}Mirror(F, lineOfReflection) → F'_{3}Polygon(A'_{3}, B'_{3}, C'_{3}, D'_{3}, E'_{3}, F'_{3}) → interimRT, a'_{3}, b'_{3}, c'_{3}, d'_{3}, e'_{3}, f'_{3}Point(Circle[U, 1.2935928228236204]) → B_2Polygon(U, B_2, W, Z, G_1, H_1) → image, u, v, w, z_1, g_1, h_1Translate(A'_{3}, GRVector) → MTranslate(B'_{3}, GRVector) → B'Translate(C'_{3}, GRVector) → OTranslate(D'_{3}, GRVector) → PTranslate(E'_{3}, GRVector) → QTranslate(F'_{3}, GRVector) → RPolygon(M, B', O, P, Q, R) → finalRT, m, n, o, p, q, rTranslate(B, GRVector) → B'_{2}Translate(C, GRVector) → C'Translate(D, GRVector) → D'Translate(E, GRVector) → E'Translate(F, GRVector) → F'Polygon(A', B'_{2}, C', D', E', F') → intermTR, a', b'_{2}, c', d', e', f'Mirror(B'_{2}, lineOfReflection) → B''Mirror(C', lineOfReflection) → C''Mirror(D', lineOfReflection) → D''Mirror(E', lineOfReflection) → E''Mirror(F', lineOfReflection) → F''Polygon(A'', B'', C'', D'', E'', F'') → finalTR, a'', g, c'', d'', e'', f''Translate(B, Vector[(anim1 * GRVector)]) → B'_{4}Translate(C, Vector[(anim1 * GRVector)]) → C'_{2}Translate(D, Vector[(anim1 * GRVector)]) → D'_{2}Translate(E, Vector[(anim1 * GRVector)]) → E'_{2}Translate(F, Vector[(anim1 * GRVector)]) → F'_{2}Translate(A, Vector[(anim1 * GRVector)]) → A'_{2}Polygon(A'_{2}, B'_{4}, C'_{2}, D'_{2}, E'_{2}, F'_{2}) → interimTRsliding, a'_{2}, b'_{4}, c'_{2}, d'_{2}, e'_{2}, f'_{2}Polygon(A''_{moving}, B''_{moving}, C''_{moving}, D''_{moving}, E''_{moving}, F''_{moving}) → intermTRflipping, a''_{moving}, b''_{moving}, c''_{moving}, d''_{moving}, e''_{moving}, f''_{moving}Polygon(A'_{1moving}, B'_{1moving}, C'_{1moving}, D'_{1moving}, E'_{1moving}, F'_{1moving}) → interimRTflipping, a'_{1moving}, b'_{1moving}, c'_{1moving}, d'_{1moving}, e'_{1moving}, f'_{1moving}Translate(A'_{3}, Vector[(anim2 * GRVector)]) → GTranslate(B'_{3}, Vector[(anim2 * GRVector)]) → HTranslate(C'_{3}, Vector[(anim2 * GRVector)]) → NTranslate(D'_{3}, Vector[(anim2 * GRVector)]) → STranslate(E'_{3}, Vector[(anim2 * GRVector)]) → TTranslate(F'_{3}, Vector[(anim2 * GRVector)]) → VTranslate(A'_{3}, Vector[(anim2 * GRVector)]) → A_1Translate(B'_{3}, Vector[(anim2 * GRVector)]) → B_1Translate(C'_{3}, Vector[(anim2 * GRVector)]) → C_1Translate(D'_{3}, Vector[(anim2 * GRVector)]) → D_1Translate(E'_{3}, Vector[(anim2 * GRVector)]) → E_1Translate(F'_{3}, Vector[(anim2 * GRVector)]) → F_1Polygon(A_1, B_1, C_1, D_1, E_1, F_1) → interimRTsliding, a_1, b_1, c_1, d_1, e_1, f_1
AI 绘图提示语参考
绘制一个由多个对应顶点组成的封闭多边形,用于展示等距变换的“先平移后反射”与其结果。先给定一组原多边形顶点,确定一条作为反射轴的直线;用从两点定义的平移向量把原顶点分别移动得到一组平移后的对应点,并连成对应多边形。再将该平移后的多边形按同一条反射轴进行镜像,得到最终对应多边形。可同时保留原图、多边形的平移像以及镜像像,突出各顶点在变换下的对应关系与轮廓衔接。
以上提示语为根据原始绘图命令整理而来,仅供参考。