Applying the trigonometric identity: $\cot\left(\theta \right) = \frac{\cos\left(\theta \right)}{\sin\left(\theta \right)}$

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

Applicare la formula: $x\cdot x$$=x^2$, dove $x=\cos\left(a\right)$

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