On two approaches of finding exact solutions to nonlinear evolution equations

In this work we give some discussions on the secq-tanhqsecq-tanhq method of finding exact solutions to the nonlinear evolution equations presented by Liu and Jiang. We conclude that the method is just one special case of the generalized projective Riccati equation method. Therefore these deformed hyperbolic function solutions do not pertain to a new class. Then based on the generalized projective Riccati equation method more exact solutions of the Hirota–Satsuma coupled KdV systems are obtained.