余弦A-B公式及其应用

GeoGebra 命令及参数

1. Circle(O, 1) → UC
2. Point(UC) → A
3. Point(UC) → B
4. Rotate((1, 0), Angle[B, O, A]) → AminB
5. Polygon(LL, LR, UR, UL) → theBox, ll, lr, ur, ul
6. Segment(O, A) → Aseg
7. Segment(O, B) → Bseg
8. Segment(O, AminB) → ABseg
9. Angle(P0, O, A) → angA
10. Midpoint(ABseg) → AminBmid
11. Midpoint(Aseg) → Asegmid
12. CircleArc(O, AminBmid, Asegmid) → Bminarc
13. Intersect(Bminarc, AngularBisector[Aseg, ABseg]) → Bminmid,
14. Midpoint(Bseg) → Bsegmid
15. Angle(AminB, O, A) → Bneg
16. Angle(B, O, A) → AminB1
17. Angle((1, 0), O, AminB) → AminBs
18. Segment(A, B) → cordAB
19. Segment((1, 0), AminB) → cordAminB
20. Angle((1, 0), O, B) → angB
21. Textfield(stuAx) → inputAx
22. Textfield(stuAy) → inputAy
23. If(step > 2, "B_T&=(\cos B, \sin B)", "") → Bttext
24. If(step > 1, "A_T&=(\cos A, \sin A)", "") → Attext
25. If(step > 3, "(A-B)_T&=\Big(\cos(A-B), \sin(A-B)\Big)", "") → ABttext
26. Textfield(stuBx) → inputBx
27. Textfield(stuBy) → inputBy
28. Textfield(stuABy) → inputABy
29. Textfield(stuABx) → inputABx
30. Textfield(stud1) → inputd1
31. Textfield(stud2) → inputd2
32. If(step > 4, "d_1&=\sqrt{(\cos B-\cos A)^2+(\sin B-\sin A)^2}", "") → d1text
33. If(step > 4, "d_2&=\sqrt{\big(\cos (A- B)-1\big)^2+ \sin^2( A-B)}", "") → d2text
34. If(showjust, stepneg1supp, "") → stepneg12