Fourier transform based on MATLAB symbolic operation;

In accordance with the functions of analytical solution and numerical solution for solving algebraical equation group,a design approach was introduced to conduct the pole placement of PI and PID controllers for first and second order controlled models using the symbolic operation.

MatLab has a strong symbolic operation function.

In this paper, a review is presented for the development in the theoretical analysis and symbolic computation of internal solitary waves in stratified fluids, including their application background, experimental reports and results in the theoretical analysis and symbolical computation as well as unsolved problems for future investigations.

In contrast to pure numerical modeling method, computer algebra system, which is characterized as symbolic calculation, is used.

Using the above results and the work previously done by authors and with the help of symbolic calculation language Mathematica TM , the authors calculate the first order Lie Bcklund invariant vector fields of high symmetry for plan elasticity equations and the Lie algebra of the stress fu.

How to use symbolic calculation of matlab in analysis of high order dynamic circuit is explained by two second order and four order examples,and relevant programs and running results are given.