Current location - Training Enrollment Network - Mathematics courses - Mathematics of liberal arts in senior two.
Mathematics of liberal arts in senior two.
Firstly, it is proved that BE is parallel to the plane ACD, BE is on the plane EBMN, and the plane EBMN and the plane ACD intersect at MN, so BE is parallel to MN, so CD is parallel to MN. You can refer to the answer to the first question of solid geometry in 20 13 Shandong science examination paper.