开放中间法：梯形面积问题的几何与积分构造

GeoGebra 命令及参数

1. Intersect(xAxis, yAxis) → A
2. Point(Ray[(0, 1), (0, 2)]) → B
3. Segment(A, B) → h
4. Ray(B, B + (1, 0)) → i
5. Point(Ray[A, A + (1, 0)]) → E
6. Segment(A, E) → j
7. Ellipse(B, E, (1 / 2 * (P - h - j))) → e
8. Intersect(e, f) → C, D
9. Polygon(B, D, E, A) → q1, b, d_1, e_1, a
10. PointIn(q1) → Pointq1
11. Midpoint(D, E) → F
12. Rotate(B, ((-π) * d), F) → B'
13. Rotate(D, ((-π) * d), F) → D'
14. Rotate(E, ((-π) * d), F) → E'
15. Rotate(A, ((-π) * d), F) → A'
16. Polygon(B', D', E', A') → q1', b', d', e', a'
17. Segment(B, D) → g
18. Segment(D, E) → k
19. Segment(A', B') → l
20. Segment(B', D') → m
21. Segment(D', E') → n
22. Segment(E', A') → p
23. Angle(E', A', B') → α
24. Angle(A', B', D') → β
25. Angle(E, A, B) → γ
26. Angle(A, B, D) → δ
27. SurdText(g) → text1
28. SurdText(k) → text2
29. SurdText(Distance[D', B']) → text3
30. Textfield(P) → InputBox1