动画161：三角形中线变换

GeoGebra 命令及参数

1. Polygon(A, B, C) → poly1, c, a, b
2. Segment(C, A) → f
3. Segment(C, B) → g
4. Midpoint(A, B) → M
5. Dilate(A, If[0 < d ≤ 1, 1 - d, 0], M) → A'
6. Segment(A, A') → h
7. Rotate(A, If[1 < d ≤ 2, ((-(d - 1)) * π), (-π)], M) → A'_1
8. Rotate(A', If[1 < d ≤ 2, ((-(d - 1)) * π), (-π)], M) → A''
9. Segment(A'_1, A'') → h'
10. Dilate(C, If[2 < d ≤ 3, 3 - d, 0], M) → C'
11. Segment(C, C') → i
12. Segment(C, M) → j