勾股定理剪切法证明
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①本范例通过剪切法演示勾股定理的证明过程;②涉及核心数学概念包括勾股定理、二次函数、等腰直角三角形、几何平均数、反射、圆;③构造要点:使用Intersect, Point, Semicircle, Midpoint, Circle, Rotate, Line, Vector, Length, If, Polygon, Angle等GeoGebra命令和对象;④适合高中数学教学和几何证明学习。
GeoGebra 命令及参数
Intersect(xAxis, yAxis) → APoint(xAxis) → BSemicircle(A, B) → hMidpoint(A, B) → OCircle(O, B) → oPoint(h) → CRotate(C, 90*°, A) → DRotate(A, 270*°, C) → ELine(D, E) → mVector(D, E) → v_bLength(v_b) → k_bRotate(C, 270*°, B) → FRotate(B, 90*°, C) → GLine(F, G) → nIntersect(m, n) → HLine(H, yAxis) → hcVector(E, H) → u_aLength(u_a) → ku_bVector(G, H) → u_bLength(u_b) → ku_aVector(F, G) → v_aLength(v_a) → k_aRotate(B, 270*°, A) → IVector(A, I) → v_cLength(v_c) → k_cCircle(H, (ku_a * ku_b / k_c)) → dIntersect(d, hc) → K, LVector(H, L) → v_hRotate(A, 90*°, B) → JIf(a < ka_1, Point[F, Vector[(a / ka_1 * u_b)]], If[a < ka_2, Point[F, u_b], Point[F, Vector[u_b + ((a - ka_2) / (1 - ka_2) * v_c)]]]) → F'Polygon(B, C, G, F) → P, b_1, c, g, fIf(a < ka_1, Point[G, Vector[(a / ka_1 * u_b)]], If[a < ka_2, Point[H, Vector[((a - ka_1) / (ka_2 - ka_1) * v_h)]], Point[L, Vector[((a - ka_2) / (1 - ka_2) * v_c)]]]) → G'If(a < ka_1, C, If[a < ka_2, Point[C, Vector[((a - ka_1) / (ka_2 - ka_1) * v_h)]], Point[C, Vector[v_h + ((a - ka_2) / (1 - ka_2) * v_c)]]]) → Ca'Vector(G', Ca') → uIf(a < ka_1, B, If[a < ka_2, B, Point[B, Vector[((a - ka_2) / (1 - ka_2) * v_c)]]]) → B'Vector(F', B') → vPolygon(B', Ca', G', F') → Q, b', c', g', f'If(b < kb_1, Point[E, Vector[(b / kb_1 * u_a)]], If[b < kb_2, Point[H, Vector[((b - kb_1) / (kb_2 - kb_1) * v_h)]], Point[L, Vector[((b - kb_2) / (1 - kb_2) * v_c)]]]) → E'If(b < kb_1, Point[D, Vector[(b / kb_1 * u_a)]], If[b < kb_2, Point[D, u_a], Point[D, Vector[u_a + ((b - kb_2) / (1 - kb_2) * v_c)]]]) → D'If(b < kb_1, C, If[b < kb_2, Point[C, Vector[((b - kb_1) / (kb_2 - kb_1) * v_h)]], Point[C, Vector[v_h + ((b - kb_2) / (1 - kb_2) * v_c)]]]) → Cb'If(b < kb_1, A, If[b < kb_2, A, Point[A, Vector[((b - kb_2) / (1 - kb_2) * v_c)]]]) → A'Polygon(A, C, E, D) → R, a_1, c_1, e, d_1Polygon(A', Cb', E', D') → S, a', cb', e', d'Polygon(A, B, J, I) → T, a_2, b_2, j, iAngle(A, C, B) → αMidpoint(C, B) → MMidpoint(A, C) → NMidpoint(a_2) → U