Applicare la formula: $a\frac{b}{c}$$=\frac{ba}{c}$, dove $a=\cos\left(x\right)^2$, $b=\sin\left(x\right)^2$ e $c=\cos\left(x\right)^2$

Applicare la formula: $\frac{a}{a}$$=1$, dove $a=\cos\left(x\right)^2$ e $a/a=\frac{\sin\left(x\right)^2\cos\left(x\right)^2}{\cos\left(x\right)^2}$