In a closed loop control system, what is the sensitivity of the gain of the overall system, M to the variation in H?
1
\(\frac{1}{{1 + G\left( s \right)H\left( s \right)}}\)
2
\(\frac{{ - G\left( s \right)H\left( s \right)}}{{1 + G\left( s \right)H\left( s \right)}}\)
3
\(\frac{{ - 1}}{{1 + G\left( s \right)H\left( s \right)}}\)
4
\(\frac{{G\left( s \right)H\left( s \right)}}{{1 + G\left( s \right)H\left( s \right)}}\)