Se $\theta \in \left(0,\frac{\pi }{2}\right)$ a expressão

$$\frac{\frac{\cos (\theta )+\mathrm{sen}(\theta )}{\mathrm{sen}(\theta )}+\frac{\cos (\theta )-\mathrm{sen}(\theta )}{\cos (\theta )}}{\frac{\cos (\theta )+\mathrm{sen}(\theta )}{\cos (\theta )}+\frac{\cos (\theta )-\mathrm{sen}(\theta )}{\mathrm{sen}(\theta )}}$$

é equivalente a