立方体中两平面的二面角

GeoGebra 命令及参数

1. Point(Circle[C, Distance[D, C], Segment[D, C]]) → B
2. Cube(D, C, B) → a, A, faceCDHG, faceEFGH, edgeAD, edgeAB, edgeBC, edgeCD, edgeAE, edgeDH, edgeEH, edgeEF, E, edgeBF, edgeFG, edgeCG, edgeGH, H, G, F, faceABCD, faceADHE, faceABFE, faceBCGF
3. Polygon(D, B, G) → poly1, g, d, b
4. Polygon(D, C, G) → poly2, g_1, d_1, c
5. Point(b) → X
6. OrthogonalPlane(X, b) → e
7. Intersect(d_1, e) → Y_1
8. Intersect(g, e) → Y
9. Intersect(edgeCG, e) → I
10. Intersect(edgeAB, e) → J
11. Polygon(X, Y_1, I) → poly3, i, K, y_1
12. Polygon(X, Y_1, Y) → poly4, L, M, y_2
13. Polygon(X, Y, J) → poly5, j, N, O
14. Angle(Y_1, X, D) → α
15. Angle(Y, X, G) → β