$$z=1+\cos \left( \frac{ \pi }{2}+\theta \right)+\text{i}\sin \left( \frac{ \pi }{2}+\theta \right)=2{{\cos }^{2}}\frac{\frac{ \pi }{2}+\theta }{2}+2\text{i}\sin \frac{\frac{ \pi }{2}+\theta }{2}\cos \frac{\frac{ \pi }{2}+\theta }{2}$$  $$=2\cos \frac{\frac{ \pi }{2}+\theta }{2}\left( \cos \frac{\frac{ \pi }{2}+\theta }{2}+\text{i}\sin \frac{\frac{ \pi }{2}+\theta }{2} \right)$$．  当$$\frac{ \pi }{2} ~\textless{} ~\theta ~~\textless{} ~ \pi $$时，$$\overline{z}=-2\cos \frac{\frac{ \pi }{2}+\theta }{2}\left( -\cos \frac{\frac{ \pi }{2}+\theta }{2}+\text{i}\sin \frac{\frac{ \pi }{2}+\theta }{2} \right)$$  $$=-2\cos \left( \frac{ \pi }{4}+\frac{\theta }{2} \right)\left( \cos \left( \frac{3 \pi }{4}-\frac{\theta }{2} \right)+\text{i}\sin \left( \frac{3 \pi }{4}-\frac{\theta }{2} \right) \right)$$．  ∴辐角主值为$$\frac{3 \pi }{4}-\frac{\theta }{2}$$． 
已知复数$$z=1-\sin \theta +\text{i}\cos \theta \left( \frac{ \pi }{2} ~\textless{} ~\theta ~~\textless{} ~ \pi \right)$$，求$$z$$的共轭复数$$\overline{z}$$的辐角主值．
Options:
$$\frac{ \pi }{4}-\frac{\theta }{2}$$ 
$$\frac{ \pi }{4}+\frac{\theta }{2}$$ 
$$\frac{3 \pi }{4}-\frac{\theta }{2}$$ 
$$\frac{3 \pi }{4}+\frac{\theta }{2}$$ 