For the unity feedback system shown below, the steady state,

For the unity feedback system shown below, the steady state, when the input is
R = 3 - 1 + 1
s s² 2s³

would be—

e_ss = _{s → 0}Lim sE (s) = _{s → 0}Lim	s·R(s)
	1 + G(s)H(s)

= _{s → 0}Lim	s		3	-	1	+	1
	1 + 4(s + 1)/s²(s + 2).1		s		s²		2s³

= _{s → 0}Lim	s³(s + 2)		3	-	1	+	1
	s³ + 2s² + 4s + 4		s		s²		2s³

= 0 + 0 + 1/4 = 1/4