特殊角的三角比

GeoGebra 命令及参数

1. Segment(A, B) → f
2. OrthogonalLine(B, f) → g
3. Rotate(B, (a * π / 180), A) → B'
4. Angle(B, A, B') → α
5. Ray(A, B') → h
6. Circle(B, 2) → c
7. Intersect(c, g, 2) → C
8. Ray(B, C) → i
9. Intersect(h, i) → D
10. Segment(B, D) → j
11. Segment(A, D) → k
12. Polygon(A, B, D) → poly1, d, a_1, b
13. Rotate(B, If[0 < e ≤ 1, (-((e * (π / 2 - α)))), α - π / 2], D) → B'_1
14. Rotate(D, If[0 < e ≤ 1, (-((e * (π / 2 - α)))), α - π / 2], D) → D'
15. Segment(B'_1, D') → j'
16. Rotate(A, If[0 < l ≤ 1, (α * l), α], A) → A'
17. Rotate(B, If[0 < l ≤ 1, (α * l), α], A) → B'_2
18. Segment(A', B'_2) → f'
19. Rotate(B, If[0 < m ≤ 1, (m * π / 2), π / 2], B) → B'_3
20. Rotate(D, If[0 < m ≤ 1, (m * π / 2), π / 2], B) → D'_1
21. Segment(B'_3, D'_1) → j'_1
22. Textfield(a) → InputBox1
23. Angle(D, B, A) → β