Тригонометричен израз

[Гост]

[tex]{1+cos\alpha \choose sin\alpha}[/tex]

[Гост]

Да се опрости

[Zarrie]

[tex]\frac{1+cos\alpha}{sin\alpha}=\frac{2cos^\cancel{2} \frac{\alpha}{2}}{2sin\frac{\alpha}{2}\cancel{cos\frac{\alpha}{2}}}=\frac{cos \frac{\alpha}{2}}{sin \frac{\alpha}{2}} = cotg \frac{\alpha}{2}[/tex]