Guadou principle is also called friendship principle: if the distance ratio of two moving points to a fixed point is constant and the included angle is constant, the motion paths of the two moving points are the same. Guadou principle is a master-slave linkage trajectory problem. Call melons on the initiative and beans on the passive. Melon moves in a straight line, so does the path of beans. Melon moves in a circle, so does the path of beans. The key is to make the trajectory of the driven point, and make the special point connection trajectory of the driven point according to the special position of the driven point.

Math:

Mathematics is a subject that studies concepts such as quantity, structure, change, space and information.

Mathematics is a universal means for human beings to strictly describe the abstract structure and mode of things, and can be applied to any problem in the real world. All mathematical objects are artificially defined in essence. In this sense, mathematics belongs to formal science, not natural science. Different mathematicians and philosophers have a series of views on the exact scope and definition of mathematics.

Mathematics plays an irreplaceable role in the development of human history and social life, and it is also an indispensable basic tool for studying and studying modern science and technology.

Refer to the above? Baidu encyclopedia-mathematics