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

Applicare la formula: $\lim_{x\to c}\left(a\right)$=indeterminate, dove $a=\frac{\sin\left(x\right)}{x\cos\left(x\right)}$, $c=\infty $ e $x->c=x\to\infty $