1. The problem statement, all variables and given/known data i meet problem below in control system : G(s)= K(s+4)/s(s+1)(s+2) its a unity feedback system. 1. determine the range of K that keeps the system stable. 2. determine the range of K that makes the system oscillate 3. calculate the frequency of oscillation when the system oscillate 2. Relevant equations characteristic equation for stability Routh Hurwitz Creation 3. The attempt at a solution i have solved the first by determine the range of K by using Routh Hurwitz Table. But, i m very confused when it comes to find the range of K that makes system oscillate. even, i dont understand the term for oscillate. conclusion number 2 and 3 is very confusing.