For the control system with open loop transfer function G\(\left( {\rm{s}} \right) = \frac{{{\rm{K}}\left( {{\rm{s}} + 2} \right)}}{{{{\rm{s}}^3} + {\rm{b}}{{\rm{s}}^2} + 4{\rm{s}} + 3}}\)  . Find the value of K if the system oscillates at a frequency of 3 rad/sec