Five Years of Magic, Three Years of Simulation

"Known: In the four-dimensional three-dimensional array, the core of the space confinement barrier is composed of two stable triangular arrays. Verification: The array substrate where the energy balance point is located must reach orthogonal resonance with the basic array substrate? " Liu Jingyang, who had just time-traveled into Caerleon, was confused and said in his heart, "Holy shit." But soon, under the influence of some kind of force, the magic terms in front of me turned into a high school math problem from the previous life on earth: "It is known that the tetrahedron ABCD is composed of four congruent equilateral triangles, and the point M is the midpoint of the edge AD. Prove: Plane MBC⊥Plane ABC." "Haha, going back to high school? It's interesting." "Then let's see if I, who scored 666 in the college entrance examination in my previous life, can get into the University of California and North Carolina in this world!"