Question
Find principal argument of $(1+\text{i}\sqrt{3})^2$

Answer

We have,
$\text{z}=(1+\text{i}\sqrt{3})^2$
$\Rightarrow\text{z}=1-3+2\text{i}\sqrt{3}$
$\Rightarrow\text{z}=-2+\text{i}(2\sqrt{3})$
So, z lies in second quadrant.
$\Rightarrow\arg(\text{z})=\pi-\tan^{-1}\Big|\frac{2\sqrt{3}}{-2}\Big|$
$\Rightarrow\arg(\text{z})=\pi-\tan^{-1}\sqrt{3}$
$\Rightarrow\arg(\text{z})=\pi-\frac{\pi}{3}$
$\Rightarrow\arg(\text{z})=\frac{2\pi}{3}$

Need a full question paper?

Generate a complete, print-ready paper with questions like this in minutes — across 16+ boards, with answer keys.

Start Generating Free