椭圆与圆的轨迹演示
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①本范例演示了通过两个圆的交点轨迹生成椭圆的过程;②涉及的核心数学概念包括圆、椭圆、轨迹、解析几何;③作图要点提炼自构造摘要,使用了Line(线段)、Circle(圆)、Intersect(交点)、Point(点)、Rotate(旋转)、Ray(射线)、Segment(线段)、CurveCartesian(笛卡尔曲线)、Polygon(多边形)、CircleArc(圆弧)等GeoGebra命令/对象;④适合高中及以上学生学习和理解椭圆的几何性质与参数方程。
GeoGebra 命令及参数
Line(A, xAxis) → nCircle(A, R) → cIntersect(c, n) → E, FPoint(c) → BCircle(A, R + r) → dRotate(F, (t * w), A) → B'Ray(A, B') → aIntersect(d, a) → C,Circle(B', C) → eRotate(C, (t * w1), B') → B''Ray(C, B'') → bSegment(C, B'') → iSegment(A, B') → jCurveCartesian(x(A) + ((R + r) * (cos((w * i)) + cos((w1 * i)))), y(A) + ((R + r) * (sin((w * i)) + sin((w1 * i)))), i, 0, t) → kPoint(i) → DIntersect(e, j) → J, KSegment(A, K) → hRay(A, B') → fIntersect(e, f) → H, IRotate(I, (t * w1), B') → I'Segment(B', I') → gCurveCartesian(x(A) + (R * cos((w * i))) + (r * cos(((w1 + w - π / 2) * i))), y(A) + (R * sin((w * i))) + (r * sin(((w1 + w - π / 2) * i))), i, 0, t) → lCurveCartesian(x(A) + (R * cos((w * i))) - (r * cos(((w1 + w) * i) + π)), y(A) + (R * sin((w * i))) - (r * sin(((w1 + w) * i) + π)), i, 0, t) → oCircle(A, R + r) → r_1Point(r_1) → LRotate(L, 120°, A) → L'Rotate(L, 240°, A) → L'_1Polygon(L'_1, L, L') → t1, l', l'_1, l_1CircleArc(L'_1, L, L') → sCircleArc(L, L', L'_1) → c_1CircleArc(L', L'_1, L) → d_1Point(c) → OSegment(O, A) → mMidpoint(O, A) → PMidpoint(g) → QSegment(A, N) → f_1Segment(A, M) → g_1Circle(A, I') → e_1Circle(A, N) → h_1Circle(A, M) → k_1Midpoint(g_1) → SMidpoint(f_1) → T