西瓦定理（塞瓦定理）的动态几何演示
2021-07-26 15:50
本范例演示西瓦定理（Ceva's Theorem），即在三角形ABC中，从三个顶点分别向对边引线段AD、BE、CF，这三条线段共点的充要条件为 (BD/DC)·(CE/EA)·(AF/FB) = 1。通过GeoGebra动态构造三角形、交点与线段，利用向量与比值计算展示定理的几何意义。用户可拖动顶点实时观察各线段比值乘积的变化，验证共点条件，直观理解三角形中线段交比与共点性的深刻联系。
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