余弦定理证明 by Pierre Lacoste
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①本范例通过动态演示证明余弦定理,适用于任意三角形;②核心数学概念为余弦定理、三角函数、几何作图;③构造要点:使用Point、Segment、OrthogonalLine、Intersect、Angle、Polygon等命令构建三角形及辅助线,展示定理推导过程;④适合高中数学教学和学生自主探究。
GeoGebra 命令及参数
Point(xAxis) → APoint(xAxis) → CSegment(A, C) → bSegment(C, B) → aSegment(B, A) → cOrthogonalLine(B, xAxis) → dIntersect(d, b) → DSegment(A, D) → kSegment(D, C) → fSegment(D, B) → hOrthogonalLine(A, a) → h_1OrthogonalLine(B, h_1) → iIntersect(h_1, i) → ESegment(E, B) → jAngle(B, D, A) → βPolygon(A, D, B) → poly1, b_1, a_1, d_1Polygon(B, D, C) → poly2, e, m, n