Wykaż, że jeżeli \(\displaystyle{ \alpha + \beta + \gamma= \pi}\), to:
1. \(\displaystyle{ \frac{\sin + \sin \beta - \sin \gamma}{\sin + \sin \beta + \sin \gamma}=\tan \frac{\alpha}{2} \tan \frac{\beta}{2}}\)
2. \(\displaystyle{ \sin 2\alpha+\sin 2\beta+ \sin 2\gamma=4\sin \sin \beta \sin \gamma}\)