Find the integrals of the functions $\frac{\cos x}{1+\cos x}$

Question

$\begin{array}{1 1}x-\tan \frac{x}{2}+c \\ x+\tan \frac{x}{2}+c \\ x-\cot \frac{x}{2}+c \\ x+\cot \frac{x}{2}+c \end{array}$