A unity feedback control system has forward loop transfer function as e^{-Ts}/s(s+1).

Its phase value will be zero at frequency ω_{1}.

Which of the following equations should be satisfied by ω_{1}?

A. ω_{1} = tan(Tω_{1})

B. ω_{1} = cot(Tω_{1})

C. Tω_{1} = cot(ω_{1})

D. Tω_{1} = tan(ω_{1})

## Show Answer

Answer: B

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