直角三角形上的正方形
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①本范例演示在直角三角形三边外侧分别作正方形,并探讨这些正方形与原三角形的关系;②涉及的核心数学概念包括勾股定理、正弦、余弦函数、向量及解析几何;③作图要点——使用 GeoGebra 命令 Point(点)、Intersect(交点)、Polygon(多边形)、Midpoint(中点)、Length(长度)、Sequence(序列);④适合高中数学教学,用于理解勾股定理的几何证明及三角函数的应用。
GeoGebra 命令及参数
Point(yAxis) → AIntersect(xAxis, yAxis) → BPoint(xAxis) → CPolygon(A, B, C) → poly1, c, a, bPolygon(A, C, 4) → poly2, f, g, h, i, D, EPolygon(B, A, 4) → poly3, j, k, l, m, F, GPolygon(C, B, 4) → poly4, n, p, q, r, H, IMidpoint(F, B) → JMidpoint(B, I) → KMidpoint(C, E) → LMidpoint(A, B) → MMidpoint(B, C) → NMidpoint(C, A) → OLength(b) → LHypSequence(A + (t * (C - A)), t, 0, 1, 1 / LHyp) → HypBSequence(E + (t * (D - E)), t, 0, 1, 1 / LHyp) → HypTSequence(A + (t * (E - A)), t, 0, 1, 1 / LHyp) → HypLSequence(C + (t * (D - C)), t, 0, 1, 1 / LHyp) → HypRSequence(Segment[Element[HypL, k], Element[HypR, k]], k, 1, LHyp) → HypLRSequence(Segment[Element[HypT, k], Element[HypB, k]], k, 1, LHyp) → HypTBLength(c) → LS1Length(a) → LS2Sequence(B + (t * (A - B)), t, 0, 1, 1 / LS1) → S1BSequence(G + (t * (F - G)), t, 0, 1, 1 / LS1) → S1TSequence(A + (t * (F - A)), t, 0, 1, 1 / LS1) → S1RSequence(B + (t * (G - B)), t, 0, 1, 1 / LS1) → S1LSequence(B + (t * (C - B)), t, 0, 1, 1 / LS2) → S2BSequence(H + (t * (I - H)), t, 0, 1, 1 / LS2) → S2TSequence(C + (t * (I - C)), t, 0, 1, 1 / LS2) → S2LSequence(B + (t * (H - B)), t, 0, 1, 1 / LS2) → S2RSequence(Segment[Element[S1L, k], Element[S1R, k]], k, 1, LS1) → S1LRSequence(Segment[Element[S2L, k], Element[S2R, k]], k, 1, LHyp) → S2LRSequence(Segment[Element[S1T, k], Element[S1B, k]], k, 1, LS1) → S1TBSequence(Segment[Element[S2T, k], Element[S2B, k]], k, 1, LS2) → S2TB