Vol. 43 No. 5 Journal of Shanghai Normal University5 Natural Sciences·MathematicsJ Oct.
I Using the method of multi-parameter perturbation theory and qualitative analysis a cubic system perturbed by degree four are investigated in this paper. After systematic analysis it is found that the studied system can have nine limit cycles with their distributions are obtained. Key wordsI PerturbationMHomoclinic orbitMMelnikov functionMbifurcationMlimit cycle. CLC numberI O 175. 12 Document codeI Afatcat:7brdugmhb5hj3eistvjwrrz44i