“…When a = 0.039, 0.046, 0.0534, zero is the largest Lyapunov exponent of system (21). System (20) presents 1-period, Let (n, b, r, µ, c, l, ω 1 , ω 2 , ε 1 , ε 2 ) = (2, 1, 0.08, 0.12, 0.4, 0.2, 1.25, √ 6, 0.5, 0.5), and the initial values of systems (20) and ( 21) are (u, v) = (1, −0.42) and (u, v, w, z, p, q) = (1, −0.42, 0.8, 0.8, 0.6, 0.6), respectively. In system (21), the largest Lyapunov exponent is zero when a = 0.035, 0.041.…”