“…For example, when (a, b, c, k) = (4, 10, 5, 0), system (26) can generate three coexisting chaotic attractors whose Lyapunov exponents are equal to 0.699, 0.457 and 0.520. Also, this system is characterized by a variable equilibriums number by varying the parameter c. If c < 16bk 2 /(4ab + 1) 2 , system (26) has three equilibriums. If c = 16bk 2 /(4ab + 1) 2 , it has four equilibriums and if c > 16bk 2 /(4ab+1) 2 , it has five equilibriums.…”