Answer:
This question is about half-angle trigonometric identities, which are specific formulas that help us to solve problems with half-angles.
In this case, if you need a half-angle identity for the tangent, you could use
[tex]tan(\frac{x}{2} )=\frac{sin(x)}{1+cos(x)}[/tex]
[tex]tan(\frac{x}{2})=\frac{1-cos(x)}{sin(x)}[/tex]
[tex]tan(\frac{x}{2})=\sqrt{\frac{1-cos(x)}{1+cos(x)} }[/tex]
Therefore, the right identity must satisfy the expression above.
