Given the unity feedback system that has a forward transfer function.
\(G\left( s \right) = \frac{{k\left( {s - 2} \right)\left( {s - 4} \right)}}{{{s^2} + 4s + 3}}\)
The gain k where the root locus crosses the 0.5 damping ratio line is ______. ( Assume distance of point A from the origin is 0.5)
1
0.12
2
0.9
3
0.24
4
1.2