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4-1.Complex numbers
medium
If $z $ is a complex number of unit modulus and argument $\theta$, then ${\rm{arg}}\left( {\frac{{1 + z}}{{1 + (\bar z)}}} \right)$ equals.
A
$ - \theta $
B
$\frac{\pi }{2} - \theta $
C
$\;\theta $
D
$\;\pi - \theta $
(JEE MAIN-2013)
Solution
$|z|=1,$ arg $z=\theta \quad z=e^{i \theta}$
$\bar{z}=\frac{1}{z}$
$\arg \left(\frac{1+z}{1+\frac{1}{z}}\right)=\arg (z)=\theta$
Standard 11
Mathematics