Extended F-expansion method and periodic wave solutions for the generalized Zakharov equations

We present an extended F-expansion method for finding periodic wave solutions of nonlinear evolution equations in mathematical physics, which can be thought of as a concentration of extended Jacobi elliptic function expansion method proposed more recently. By using the extended F-expansion, without calculating Jacobi elliptic functions, we obtain simultaneously a number of periodic wave solutions expressed by various Jacobi elliptic functions for the generalized Zakharov equations. In the limit cases, the solitary wave solutions are obtained as well.