A new expression of root locus equations is derived.

Right angle coordinate equation and polar coordinates equation mutually melt is one of places easy to make mistakes in studying Analytic geometry.

In this paper, the symmetry of curved lined given by parametric equation and polar coordinates equation is discussed and the sufficient conditions are given.

An analysis of living example was carried out by the use of C language programming and obtained the tangential polar coordinates equation of the optimal pitch curve of noncircular chain wheel.

Kinematic analysis for certain and uncertain eccentricity plane lapping processes with the ring polishing machine were studied and compared,pace vector and track equation about one point relative to examination piece on polishing pad were presented.

By explaining the method of conic "not set up " and total elimination and concluding the law of the straight-line where the mid-point trajectory and the mid-point sting are in,this paper demonstrates the method of solving the track equation where the strings of the mid-point trajectory and the mid-point strings are in.