A feedback control system is represented by its transfer function: a T(s)=- s'+(1+ K)s² +10s + (5+15K) where parameter a is a positive constant, and parameter K must also be positive. (a) Find the...

Please do correct and Only handwritten otherwise skip

Extracted text: A feedback control system is represented by its transfer function: a T(s)=- s'+(1+ K)s² +10s + (5+15K) where parameter a is a positive constant, and parameter K must also be positive. (a) Find the maximum value K can assume before the system becomes unstable (b) When K is equal to this maximum value, the system oscillates. Determine the frequency of oscillation. Can this frequency be called natural frequency?