For the system 2 the approximate time taken for a step

For the system 2 the approximate time taken for a step response to
(s + 1)

reach 98% of its final value is

Given : G(s) =	2	=	A
	s + 1		Ts + 1

∴ Time constant, T = 1
For 98%, time required = 4T = 4 sec

∴	C(s)	=	2
	R(s)		s + 1

∴ C(s) =	2	.	1
	s + 1		s

⇒ C(s) = 2		1	-	1
		s		s + 1

⇒ C(t) = 2 [1 - e^-t ] = 2 × 0.98
⇒ 1 – e^-t = 0.98
⇒ e ^–t = 0.02
⇒ t = - ln 0.2 = 3.91 sec

For the system	2	the approximate time taken for a step response to
	(s + 1)