Question

Simplify:
$\frac{1-\cos x}{1+\cos x}$.

Answer 1

Now,

$\frac{1-\cos x}{1+\cos x}$

$=\frac{2{\sin }^2\frac{x}{2}}{2{\cos }^2\frac{x}{2}}$ [ Since $1-\cos x=2{\sin }^2\frac{x}{2}$ and $1+\cos x=2{\cos }^2\frac{x}{2}$]

$={\tan }^2\frac{x}{2}$.