论文部分内容阅读
1.(满分20分)这里有全等的两幅小鸭子的图像(见下图).它们的位置是随意摆放的(对应部位的连线不平行).请你证明其中的一幅是由另一幅围绕平面上某一个点(旋转中心)旋转得到的.请你把这个旋转中心找出来,并且证明这个结论.
1. (out of 20 points) Here are the images of the two ducks that are congruent (see the picture below). Their positions are randomly placed (the lines of the corresponding parts are not parallel). Please prove that one of them By another around a plane on a point (center of rotation), please find out the center of rotation, and prove this conclusion.