三角形反射与对称变换演示
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该范例通过GeoGebra动态展示一个三角形关于某条直线(或轴)进行反射(镜像)后,得到其对称像的过程,并同时呈现多个相关几何对象(如反射后的三角形、辅助线段、角度、统计特征等)的联动变化。核心数学概念包括平面几何中的反射变换、轴对称、对称性、向量(二维向量)以及单位圆上的角度关系。作图要点:使用Polygon命令构造原始三角形(顶点A、B、C),利用Mirror命令生成反射后的三角形(顶点A2、B2、C2等),并通过Segment、Angle、TableText等命令绘制辅助线段、标注角度和生成数据表格;同时涉及SD(标准差)等统计特征,可能用于分析反射前后图形的几何量。该范例适合初中至高中阶段的学生学习几何变换、对称性质以及动态数学软件的操作,也可用于教师课堂演示,帮助学生直观理解反射变换对图形位置、形状和度量属性的影响。
GeoGebra 命令及参数
Polygon(A, B, C) → D2, E2, F2, G2Mirror(A2, F2) → A3Mirror(B2, G2) → B3Mirror(C2, E2) → C3Polygon(A3, B3, C3) → D3, E3, F3, G3Mirror(A3, F3) → A4Mirror(B3, G3) → B4Mirror(C3, E3) → C4Polygon(A4, B4, C4) → D4, E4, F4, G4Mirror(A4, F4) → A5Mirror(B4, G4) → B5Mirror(C4, E4) → C5Polygon(A5, B5, C5) → D5, E5, F5, G5Mirror(A5, F5) → A6Mirror(B5, G5) → B6Mirror(C5, E5) → C6Polygon(A6, B6, C6) → D6, E6, F6, G6Mirror(A6, F6) → A7Mirror(B6, G6) → B7Mirror(C6, E6) → C7Polygon(A7, B7, C7) → D7, E7, F7, G7Mirror(A7, F7) → A8Mirror(B7, G7) → B8Mirror(C7, E7) → C8Polygon(A8, B8, C8) → D8, E8, F8, G8Mirror(A8, F8) → A9Mirror(B8, G8) → B9Mirror(C8, E8) → C9Polygon(A9, B9, C9) → D9, E9, F9, G9Mirror(A9, F9) → A10Mirror(B9, G9) → B10Mirror(C9, E9) → C10Polygon(A10, B10, C10) → D10, E10, F10, G10Mirror(A10, F10) → A11Mirror(B10, G10) → B11Mirror(C10, E10) → C11Polygon(A11, B11, C11) → D11, E11, F11, G11SD({E2, F2, G2}) → J2SD({E3, F3, G3}) → J3SD({E4, F4, G4}) → J4SD({E5, F5, G5}) → J5SD({E6, F6, G6}) → J6SD({E7, F7, G7}) → J7SD({E8, F8, G8}) → J8SD({E9, F9, G9}) → J9SD({E10, F10, G10}) → J10SD({E11, F11, G11}) → J11Segment(A2, B2) → H2Segment(A3, B3) → H3Segment(A4, B4) → H4Segment(A5, B5) → H5Segment(A6, B6) → H6Segment(A7, B7) → H7Segment(A8, B8) → H8Segment(A9, B9) → H9Segment(A10, B10) → H10Segment(A11, B11) → H11Angle(D2) → α, β, γAngle(D2) → K2, L2, M2Angle(D3) → K3, L3, M3Angle(D4) → K4, L4, M4Angle(D5) → K5, L5, M5Angle(D6) → K6, L6, M6Angle(D7) → K7, L7, M7Angle(D8) → K8, L8, M8Angle(D9) → K9, L9, M9Angle(D10) → K10, L10, M10Angle(D11) → K11, L11, M11SD({K2, L2, M2}) → I2SD({K3, L3, M3}) → I3SD({K4, L4, M4}) → I4SD({K5, L5, M5}) → I5SD({K6, L6, M6}) → I6SD({K7, L7, M7}) → I7SD({K8, L8, M8}) → I8SD({K9, L9, M9}) → I9SD({K10, L10, M10}) → I10SD({K11, L11, M11}) → I11TableText({{F1, G1, H1, I1}, {F2, G2, H2, I2}, {F3, G3, H3, I3}, {F4, G4, H4, I4}, {F5, G5, H5, I5}, {F6, G6, H6, I6}, {F7, G7, H7, I7}, {F8, G8, H8, I8}, {F9, G9, H9, I9}, {F10, G10, H10, I10}, {F11, G11, H11, I11}}, "|_") → text1SD({K2, L2, M2}) → N2SD({K3, L3, M3}) → N3SD({K4, L4, M4}) → N4SD({K5, L5, M5}) → N5SD({K6, L6, M6}) → N6SD({K7, L7, M7}) → N7SD({K8, L8, M8}) → N8SD({K9, L9, M9}) → N9SD({K10, L10, M10}) → N10SD({K11, L11, M11}) → N11TableText({{K1, L1, M1, N1}, {K2, L2, M2, N2}, {K3, L3, M3, N3}, {K4, L4, M4, N4}, {K5, L5, M5, N5}, {K6, L6, M6, N6}, {K7, L7, M7, N7}, {K8, L8, M8, N8}, {K9, L9, M9, N9}, {K10, L10, M10, N10}, {K11, L11, M11, N11}}, "|_") → text2