废纸几乎可以随手可得,加工起来简单又方便,用纸可以玩很多游戏,也可以做各种演示,有时还真起到很大作用。比如你能想象只有一个面和一个边的结构吗?对,这种结构就是著名的莫比乌斯环,也称莫比乌斯带,它还有很多奇特的性质,那我们就找一张纸、一把剪刀和一瓶胶水来演示一下吧。找一张A4大小的纸,裁成有一定宽度的纸条,如果把纸条对头粘起来,形成一个圆环,它有两个面和两条边。如果在粘的时候把一端翻转180°(“扭曲”一次),两个面就连通在一起了,两条边也连成一条边了。这在数学上叫做单侧曲面,不信你用笔从这个圈的一面开始,沿着与边平行的方向画一条线(离边的距离相等),最后还会回到起点。这种单侧曲面在数学的积分运算中 Waste paper can be readily available, simple and convenient processing, the paper can play a lot of games, you can also do a variety of presentations, sometimes really play a big role. For example, can you imagine that there is only one side and one side of the structure? Yes, this structure is the famous Mobius ring, also known as Mobius band, it has a lot of peculiar nature, then we find a Paper, a pair of scissors and a bottle of glue to demonstrate it. Find a piece of A4 size paper, cut into a certain width of the note, if the piece of paper glued together to form a ring, it has two sides and two sides. If you flip one end 180 ° ( “twist ” once) while gluing, the two faces are connected together, and the two edges are joined together. This is mathematically called unilateral surface, do not believe you pen from the side of this circle, draw a line along the parallel direction (from the edge of the same distance), and finally will be back to the starting point. This unilateral surface in the mathematical integral operation