Applicare l'identità trigonometrica: $\tan\left(\theta \right)$$=\frac{\sin\left(\theta \right)}{\cos\left(\theta \right)}$, dove $x=15$

Applicare la formula: $a+\frac{b}{c}$$=\frac{b+ac}{c}$, dove $a=1$, $b=-\sin\left(15\right)$, $c=\cos\left(15\right)$, $a+b/c=1+\frac{-\sin\left(15\right)}{\cos\left(15\right)}$ e $b/c=\frac{-\sin\left(15\right)}{\cos\left(15\right)}$

Applicare la formula: $1x$$=x$, dove $x=\cos\left(15\right)$

Applicare la formula: $\frac{\frac{a}{b}}{\frac{c}{f}}$$=\frac{af}{bc}$, dove $a=2\sin\left(15\right)$, $b=\cos\left(15\right)$, $a/b/c/f=\frac{\frac{2\sin\left(15\right)}{\cos\left(15\right)}}{\frac{-\sin\left(15\right)+\cos\left(15\right)}{\cos\left(15\right)}}$, $c=-\sin\left(15\right)+\cos\left(15\right)$, $a/b=\frac{2\sin\left(15\right)}{\cos\left(15\right)}$, $f=\cos\left(15\right)$ e $c/f=\frac{-\sin\left(15\right)+\cos\left(15\right)}{\cos\left(15\right)}$

Applicare la formula: $\frac{a}{a}$$=1$, dove $a=\cos\left(15\right)$ e $a/a=\frac{2\sin\left(15\right)\cos\left(15\right)}{\cos\left(15\right)\cdot \left(-\sin\left(15\right)+\cos\left(15\right)\right)}$