23.
그림의 블록선도와 같이 표현되는 제어 시스템의 전달함수 \(C(s)\)는?
①
\(\dfrac{G_1(s)G_2(s)}{1+G_2(s)G_3(s)+G_1(s)G_2(s)G_4(s)}\)
②
\(\dfrac{G_3(s)G_4(s)}{1+G_2(s)G_3(s)+G_1(s)G_2(s)G_4(s)}\)
③
\(\dfrac{G_1(s)G_2(s)}{1+G_1(s)G_2(s)+G_1(s)G_2(s)G_3(s)}\)
④
\(\dfrac{G_3(s)G_4(s)}{1+G_1(s)G_2(s)+G_1(s)G_2(s)G_3(s)}\)