Wykaż poprawnosc rozsamosci

[-=Prezes=-]

\(\displaystyle{ \frac{cos \alpha + cos4 \alpha + cos7 \alpha }{sin \alpha + sin4 \alpha + sin7 \alpha }= ctg4 \alpha}\)



\(\displaystyle{ \frac{cos \frac{ \alpha + \beta}{2} }{cos \frac{ \alpha - \beta}{2} } = \frac{sin( \alpha + \beta)}{sin \alpha + sin \beta}}\)

[frej]

1.
\(\displaystyle{ cos x + cos 7x = \ldots}\)
\(\displaystyle{ sinx + sin 7x =}\)

2.

\(\displaystyle{ sin 2 \frac{x+y}{2} = sin 2\theta = \ldots}\)
\(\displaystyle{ sin x + sin y =}\)