球面三角形：象限三角形

GeoGebra 命令及参数

1. Sphere((0, 0, 0), 1) → a
2. Intersect(yAxis, a, 1) → A
3. Intersect(xAxis, a, 2) → B
4. CurveCartesian(cos(t), sin(t), 0, t, -90*°, 0*°) → b
5. PointIn(a) → C
6. Plane(C, D, A) → c
7. OrthogonalLine(D, c) → d
8. Plane(A, d) → e
9. OrthogonalLine(D, e) → f
10. Intersect(f, a, 2) → F
11. CurveCartesian((x(A) * cos(t)) + (x(F) * sin(t)), (y(A) * cos(t)) + (y(F) * sin(t)), (z(A) * cos(t)) + (z(F) * sin(t)), t, 0, Angle[A, D, C]) → g
12. Plane(C, D, B) → h
13. OrthogonalLine(D, h) → i
14. Plane(B, i) → j
15. OrthogonalLine(D, j) → k
16. Intersect(k, a, 2) → E
17. Segment(A, D) → m
18. Segment(D, B) → n
19. Angle(A, D, B) → α
20. Angle(C, D, B) → β
21. CurveCartesian((x(B) * cos(t)) + (x(E) * sin(t)), (y(B) * cos(t)) + (y(E) * sin(t)), (z(B) * cos(t)) + (z(E) * sin(t)), t, 0, β) → l
22. Segment(D, C) → p
23. OrthogonalPlane(C, p) → o