A unity feedback control system has an open-loop transfer function,
\(G\left( s \right)H\left( s \right) = \frac{K}{{s\left( {s + 2} \right)\left( {s + 4} \right)}}\)
What is the value of K so that the gain margin of the system becomes 20 dB?
Enter numerical value using the virtual keypad. Round off where necessary.