中国物理B ›› 2006, Vol. 15 ›› Issue (5): 895-898.doi: 10.1088/1009-1963/15/5/002

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Direct method of finding first integral of two-dimensional autonomous systems in polar coordinates

汪文珑1, 楼智美2   

  1. (1)Department of Mathematics, Shaoxing College of Arts and Sciences, Shaoxing 312000, China; (2)Department of Physics, Shaoxing College of Arts and Sciences, Shaoxing 312000, China
  • 收稿日期:2005-08-27 修回日期:2005-12-08 出版日期:2006-05-20 发布日期:2006-05-20

Direct method of finding first integral of two-dimensional autonomous systems in polar coordinates

Lou Zhi-Mei (楼智美)a, Wang Wen-Long (汪文珑)b   

  1. a Department of Physics, Shaoxing College of Arts and Sciences, Shaoxing 312000, China; b Department of Mathematics, Shaoxing College of Arts and Sciences, Shaoxing 312000, China
  • Received:2005-08-27 Revised:2005-12-08 Online:2006-05-20 Published:2006-05-20

摘要: A direct method to find the first integral for two-dimensional autonomous system in polar coordinates is suggested. It is shown that if the equation of motion expressed by differential 1-forms for a given autonomous Hamiltonian system is multiplied by a set of multiplicative functions, then the general expression of the first integral can be obtained. An example is given to illustrate the application of the results.

关键词: direct method, autonomous systems, first integral, polar coordinates

Abstract: A direct method to find the first integral for two-dimensional autonomous system in polar coordinates is suggested. It is shown that if the equation of motion expressed by differential 1-forms for a given autonomous Hamiltonian system is multiplied by a set of multiplicative functions, then the general expression of the first integral can be obtained. An example is given to illustrate the application of the results.

Key words: direct method, autonomous systems, first integral, polar coordinates

中图分类号:  (Lagrangian and Hamiltonian mechanics)

  • 45.20.Jj
45.05.+x (General theory of classical mechanics of discrete systems)