1.
Let A={θ(π2,π):3+2isinθ12isinθ is purely imaginary}A = \left\{\theta \in \left(-\dfrac{\pi}{2}, \pi\right) : \dfrac{3 + 2i\sin\theta}{1 - 2i\sin\theta} \text{ is purely imaginary}\right\}. Then the sum of the elements in AA is: