Fórmulas del Ángulo Mitad

$$sen(\frac{\theta}{2})= \pm \sqrt{\frac{1 - cos \theta}{2}}$$

$$cos(\frac{\theta}{2})= \pm \sqrt{\frac{1 + cos \theta}{2}}$$

$$tan(\frac{\theta}{2})= \pm \sqrt{\frac{1 - cos \theta}{1 + cos \theta}}$$