1.The sum of all possible values of θ∈[−π,2π]\theta \in [-\pi, 2\pi]θ∈[−π,2π] for which 1+icosθ1−icosθ\dfrac{1 + i\cos\theta}{1 - i\cos\theta}1−icosθ1+icosθ is purely imaginary, is equal to:a.3π3\pi3πb.2π2\pi2πc.5π5\pi5πd.4π4\pi4πLogin to continueOnly logged in users canattempt or see the solution.