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Question

Mathematics Question on Complex Numbers and Quadratic Equations

If zz is a complex number of unit modulus and argument θ,\theta , then arg(1+z1+zˉ) \, arg \left(\frac{1 + z}{1 + \bar{z}}\right) is equal to

A

θ-\theta

B

π2θ\frac{\pi}{2}-\theta

C

θ\theta

D

πθ\pi - \theta

Answer

θ\theta

Explanation

Solution

The correct option is(C): θ.

Given, |z | = 1, arg 2 =θz=eiθ\theta \therefore \, z=e^{i\theta}
But zˉ=1z\bar{z}=\frac{1}{z}
arg(1+z1+12)=arg(z)=θ\therefore arg \bigg( \frac{1+z}{1+\frac{1}{2}}\bigg)=arg (z) =\theta