“…A fourth-order MRK method of five-stage is given as follows [10]: To construct a modified RK method, we set 𝑑 2 , 𝑑 3 , and 𝑑 4 as free parameters and the other parameters are the same as in Table 2. Motivated by the approach in [8], we obtain the phase lag, phase lag derivative and the amplification factor, which depend on 𝑑 2 , 𝑑 3 and 𝑑 4 as follow: Now, solving equations ( 6), (7), and (8), we get the values of free parameters in terms of 𝑧, and the expressions are too complicated, we use the following Taylor series expressions,…”