$\pm\sqrt{\frac{1+\cos2x}{2}}$

$\pm\sqrt{\frac{1-\cos2x}{2}}$

$\pm\sqrt{\frac{1+\cos x}{2}}$

$\pm\sqrt{\frac{1-\cos x}{2}}$

 $\pm\sqrt{\frac{1+\cos x}{2}}$ 

 $\pm\sqrt{\frac{1-\cos x}{2}}$ 

 $\pm\sqrt{\frac{1+\cos x}{4}}$ 

 $\pm\sqrt{\frac{1-\cos x}{4}}$ 

 $\pm\sqrt{\frac{1-\cos2x}{2}}$ 

 $\pm\sqrt{\frac{1+\cos2x}{2}}$ 

 $\pm\sqrt{\frac{1+\cos2x}{4}}$ 

 $\pm\sqrt{\frac{1-\cos2x}{4}}$