1) \(\displaystyle{ \frac{ \cos7^{\circ}\cos10^{\circ} + \cos87^{\circ}\sin367^{\circ} }{ \sin440^{\circ} }}\)
2) \(\displaystyle{ \sin200^{\circ}\sin31^{\circ}+\cos340^{\circ}\cos50^{\circ}}\)
3) Udowodnij, że jeśli \(\displaystyle{ \alpha + \beta + \gamma = 90^{\circ}}\) i \(\displaystyle{ \cos\alpha\cos\beta\cos\gamma 0}\), to \(\displaystyle{ \tg\alpha\tg\beta+\tg\beta\tg\gamma+\tg\gamma\tg\alpha=1}\)