Aplicamos a regra: $\frac{\frac{a}{b}}{c}$$=\frac{a}{bc}$, onde $a=r$, $b=4+\cot\left(x\right)$, $c=4\csc\left(x\right)+\sec\left(x\right)$, $a/b/c=\frac{\frac{r}{4+\cot\left(x\right)}}{4\csc\left(x\right)+\sec\left(x\right)}$ e $a/b=\frac{r}{4+\cot\left(x\right)}$