Surprising Property of Hyperbolas: Tangent Circles and Asymptote Segments
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①This example demonstrates that for each hyperbola in a family sharing the same pair of vertices, every circle tangent to both branches cuts equal-length segments along each asymptote, revealing a hidden geometric invariant. ②Core mathematical concepts include hyperbola definitions, asymptotes, tangent properties of circles, symmetry, and distance relations in analytic geometry. ③Construction details: Using GeoGebra commands such as Hyperbola, Segment, LineBisector, Intersect, Circle, Point, Tangent, Mirror, OrthogonalLine, and Asymptote, the construction builds foci, vertices, tangent circles, and asymptotes, with sliders (animate, button1) to dynamically explore different hyperbolas and verify the invariant. ④Suitable for high school to undergraduate courses in analytic geometry or geometric construction, ideal for inquiry-based learning to help students intuitively grasp the deep connection between hyperbola families and tangent circles.
GeoGebra Commands & Parameters
Hyperbola(F_1, F_2, C_1) → cSegment(F_1, F_2) → aLineBisector(F_1, F_2) → bIntersect(c, a, 2) → AIntersect(c, a, 1) → BIntersect(b, a) → CCircle(C, A) → dPoint(c) → DTangent(D, c) → e,Segment(F_1, D) → fSegment(D, F_2) → gMirror(D, b) → D'OrthogonalLine(D, e) → hIntersect(b, h) → ECircle(E, D) → kSegment(A, B) → iAsymptote(c) → j, lIntersect(k, l, 2) → FIntersect(k, l, 1) → GIntersect(k, j, 1) → HIntersect(k, j, 2) → ISegment(F, G) → mSegment(H, I) → n