sin^2\alpha+cos^2\alpha=1 jedynka trygonometryczna
sin^2\alpha+(\frac{3}{5})^2=1
sin^2\alpha+\frac{9}{25}=1 \ |-\frac{9}{25}
sin^2\alpha=\frac{16}{25}
sin\alpha=\sqrt{\frac{16}{25}}
sin\alpha=\frac{4}{5}
tg\alpha=\frac{sin\alpha}{cos\alpha}=\frac{\frac{4}{5}}{\frac{3}{5}}=\frac{4}{\not5^1}\cdot \frac{\not5^1}{3}=\frac{4}{3}
ctg\alpha=\frac{1}{tg\alpha}=\frac{1}{\frac{4}{3}}=\frac{3}{4}