Answer by Kunal Yadav for Why is $\cos(x)^2$ written as $\cos^2(x)$?

Well because when you write $$ \cos(x)^2 $$ it can be misunderstood as cosine of (square of x) not the square of the whole value so to avoid confusion its written as $$\cos^2(x)=(\cos(x))^2$$