Odpowiedź:
[tex] \cos \alpha = 0.8 = \frac{4}{5} \\ \\ { \sin }^{2} \alpha + { \cos }^{2} \alpha = 1 \\ { \sin}^{2} \alpha + ( \frac{4}{5} {)}^{2} = 1 \\ { \sin }^{2} \alpha + \frac{16}{25} = 1 \\ { \sin}^{2} \alpha = \frac{9}{25} \\ \sin( \alpha ) = \sqrt{ \frac{9}{25} } = \frac{3}{5} \\ \\ tg \alpha = \frac{sin \alpha }{cos \alpha } = \frac{ \frac{3}{5} }{ \frac{4}{5} } = \frac{3}{5} \times \frac{5}{4} = \frac{3}{4} = 0.75[/tex]
odp. istnieje taki kat
