用几何作图展示对数与定积分的关系(任务6)
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该范例通过一组几何构造与辅助几何变换,直观演示包含对数刻画的量如何与“确定积分”所代表的面积/累积量联系起来。核心数学概念包括:对数函数(Logarithm)、由几何刻画得到的定积分思想(Definite Integral)、以及在图形中使用角与比例关系来搭建可计算对象。作图要点上,基于多边形与基本几何实体建立框架,使用 GeoGebra 的 Polygon 生成多边形轮廓,Circle 构造圆,Line 与 Segment 提供边界与线段,Intersect 用于求交点,Midpoint 用于中点定位;通过 OrthogonalLine 构造垂线并用 Angle 控制/标注关键角度;进一步用 Rotate、RotateText、Dilate、Translate 与 Vector 完成旋转、缩放、平移等变换,从而将中间几何量映射到目标表达式。适合高中到大学初级阶段的几何作图、函数建模与微积分直观教学,也可用于对数与积分概念的可视化演示与课堂探究。
GeoGebra 命令及参数
Polygon(A, B, C) → t1, c, a, bOrthogonalLine(C, b) → fCircle(C, 1) → dIntersect(d, f, 1) → DSegment(A, D) → gOrthogonalLine(D, g) → hCircle(D, 1) → eIntersect(e, h, 2) → ESegment(A, E) → iOrthogonalLine(E, i) → jCircle(E, 1) → kIntersect(k, j, 2) → FSegment(A, F) → lOrthogonalLine(F, l) → mCircle(F, 1) → pIntersect(p, m, 2) → GSegment(A, G) → nOrthogonalLine(G, n) → qCircle(G, 1) → rIntersect(r, q, 2) → HSegment(A, H) → sOrthogonalLine(H, s) → tCircle(H, 1) → c_1Intersect(c_1, t, 2) → ISegment(A, I) → f_1OrthogonalLine(I, f_1) → g_1Circle(I, 1) → d_1Intersect(d_1, g_1, 2) → JSegment(A, J) → h_1OrthogonalLine(J, h_1) → i_1Circle(J, 1) → e_1Intersect(e_1, i_1, 2) → KSegment(A, K) → j_1OrthogonalLine(K, j_1) → k_1Circle(K, 1) → p_1Intersect(p_1, k_1, 2) → LSegment(A, L) → l_1OrthogonalLine(L, l_1) → m_1Circle(L, 1) → q_1Intersect(q_1, m_1, 2) → MSegment(A, M) → n_1OrthogonalLine(M, n_1) → r_1Circle(M, 1) → s_1Segment(C, D) → m_2Segment(D, E) → n_2Segment(E, F) → p_2Segment(F, G) → q_2Segment(G, H) → r_2Segment(H, I) → s_2Segment(I, J) → t_2Segment(J, K) → a_2Segment(K, L) → b_2Segment(L, M) → f_3Angle(C, B, A) → αAngle(D, C, A) → βAngle(E, D, A) → γAngle(F, E, A) → δAngle(G, F, A) → εAngle(H, G, A) → ζAngle(I, H, A) → ηAngle(J, I, A) → θAngle(K, J, A) → ιAngle(L, K, A) → κAngle(M, L, A) → λSegment(A, B) → l_3Segment(C, B) → m_3Segment(C, A) → n_3RotateText(text1_{1}, atand(Slope[n_3])) → text2RotateText(text3, atand(Slope[g])) → text4Midpoint(f_1) → SMidpoint(n_1) → TRotateText(text5, pi / 4) → text6RotateText(text7, atan(Slope[g])) → text8RotateText(text9, atand(Slope[i])) → text10Rotate(D, If[0 < o ≤ 1, ((-o) * pi / 3), ((-pi)) / 3], E) → D'Rotate(E, If[0 < o ≤ 1, ((-o) * pi / 3), ((-pi)) / 3], E) → E'Segment(D', E') → p_3Rotate(D', If[1 < o ≤ 2, ((-(o - 1)) * pi), (-pi)], D') → D''Rotate(E', If[1 < o ≤ 2, ((o - 1) * pi), pi], D') → E''Segment(D'', E'') → q_3Dilate(A, If[3 < o ≤ 4, 4 - o, 0], I) → A'Vector(A, A') → uTranslate(C, u) → C'Translate(A, u) → A'_{1}Segment(C', A'_{1}) → r_3Translate(C, u) → C'_{1}Angle(A, I, C'_{1}) → σRotate(C', If[4 < o ≤ 5, ((-(o - 4)) * σ), (-σ)], I) → C''Rotate(A'_{1}, If[4 < o ≤ 5, ((-(o - 4)) * σ), (-σ)], I) → USegment(C'', U) → s_3Segment(A, S) → t_3Segment(S, I) → a_3Rotate(C'', If[5 < o ≤ 6, ((o - 5) * pi), pi], S) → C'''Rotate(U, If[5 < o ≤ 6, ((o - 5) * pi), pi], S) → U'Segment(C''', U') → b_3Angle(I, A, M) → τRotate(U', If[7 < o ≤ 8, ((o - 7) * τ), τ], A) → U''Dilate(A, If[7 < o ≤ 8, 8 - o, 0], M) → A'_{2}Vector(A, A'_{2}) → vTranslate(A, v) → A'_{3}Translate(D, v) → D'_{1}Segment(A'_{3}, D'_{1}) → g'Segment(M, T) → c_3Segment(T, A) → d_3Line(M, A) → e_3Point(e_3) → VAngle(D, A, V) → χRotate(A'_{3}, If[8 < o ≤ 9, ((o - 8) * χ), χ], M) → WRotate(D'_{1}, If[8 < o ≤ 9, ((o - 8) * χ), χ], M) → ZSegment(W, Z) → g''Rotate(W, If[9 < o ≤ 10, ((-(o - 9)) * pi), (-pi)], Z) → W'Rotate(Z, If[9 < o ≤ 10, ((o - 9) * pi), pi], Z) → Z'Segment(W', Z') → g'''Polygon(A, B, C) → t2, c_4, a_4, b_4Polygon(A, C, D) → t3, d_4, a_5, c_5Polygon(A, D, E) → t4, e_4, a_6, d_5Circle(A, Distance[A, C]) → k_4Polygon(A, H, I) → t5, i_5, a_7, h_5Polygon(A, L, M) → t6, m_5, a_8, l_5RotateText(text12, atand(Slope[c_3] + pi / 2)) → text13RotateText(text13, pi) → text14
AI 绘图提示语参考
从点A出发,依次构造一系列单位圆,每个圆与前一个圆的切线相交,形成新的点。具体地,先画一个三角形,从顶点C作对边的垂线,交单位圆于一点D;连接A与D,再过D作该线段的垂线,交下一个单位圆于E;如此反复,每次以新点为圆心作单位圆,并作垂线交圆得下一点,直至得到点M。最后用线段依次连接C、D、E、F、G、H等点,形成一条折线,展示对数与定积分面积之间的几何联系。
以上提示语为根据原始绘图命令整理而来,仅供参考。