E6.14 By using magnetic bearings, a rotor is supported contactless. The technique of contactless support for rotors becomes more important in light and heavy industrial applications [14]. The matrix differential equation for a magnetic bearing system is

0 5 -1 *(1) 2 -4 7 x(t), -13 4 where x(t)=(y(t), y(t), i(t)), y(t) = bearing gap, and i(t) is the electromagnetic current. Determine whether the system is stable.