New exact periodic solutions to a category of nonlinear evolution equations

Based on the original expansion method of Jacobi elliptic function,other Jacobi elliptic functions—Glaisher symbol are introduced and expansion method of Jacobi elliptic function presented by Liu is expanded.Taking the mBBM equation and Gardner equation as examples,a series of new exact periodic solutions are obtained for these equations is found with the help of mathematics software—Mathematica.These solutions can degenerate into solitary wave solutions or trigonometric function solutions under a critical condition.