Question

The forward path transfer function is given by G(s) = 2/s(s+3). Obtain an expression for unit step response of the system.

(a) 1+2e^-t+e^-2t

(b) 1+e^-t-2e^-2t

(c) 1-e^-t+2e^-2t

(d) 1-2e^-t+e^+2t

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Asked question is from Time Response of Second Order Systems in chapter Time Response Analysis, Design Specifications and Performance Indices of Control Systems

Answer 1

The correct answer is (d) 1-2e^-t+e^+2t

Explanation: C(s)/R(s) = s/(s^2+3s+2)

C(s) = 1/s-2/s+1+1/s+2

c(t) = 1-2e^-t+e^+2t.