MathematicsMedium53×since 2002Q3170The sum of all possible values of θ∈[−π,2π]\theta \in[-\pi, 2 \pi]θ∈[−π,2π], for which 1+icosθ1−2icosθ\frac{1+i \cos \theta}{1-2 i \cos \theta}1−2icosθ1+icosθ is purely imaginary, is equal to :A4π4 \pi4πB3π3 \pi3πC2π2 \pi2πD5π5 \pi5πCheck answerSkip