When I say $ z = r(\cos \theta + i \sin \theta)$
There are two ways we can find it’s square value ,
$z^2 = r^2(x^2 + y^2) = r^2(\cos \theta^2 + i \sin \theta^2)$ (Here I did the $x^2$ and $y^2$ separately)
Ok but if we directly square $= r(\cos \theta + i \sin \theta)$ this
Then , should we also get $2\sin\theta \cos \theta$ which means $ r^2(\cos \theta + \sin\theta)^2$
Why not in 1st one because when x = r cos theta , we will only get r ^2 = cos ^2 theta .
