الف) $\frac{1}{\cos \alpha} + \cot \alpha = \frac{1}{\sin \alpha}$

ب) $\frac{\sin \alpha}{1 + \cos \alpha} = \frac{1 - \cos \alpha}{\sin \alpha}$

ج) $\frac{1}{\sin \alpha} - \cot \alpha = \frac{\sin \alpha}{1 + \cos \alpha}$

د) $1 - \sin^2 \alpha = \frac{\cos \alpha}{1 + \cos \alpha}$

ه) $\frac{1 + \cot \alpha}{1 + \tan \alpha} = \cot \alpha$