kat-alpha-jest-ostry-oraz-displaystyle-sinalpha-frac45-wtedy

$\displaystyle \cos\alpha= \frac{1}{5}$\displaystyle \cos\alpha= \frac{1}{5}

$\displaystyle \cos\alpha= -\frac{1}{5}$\displaystyle \cos\alpha= -\frac{1}{5}

$\displaystyle \cos\alpha= -\frac{3}{5}$\displaystyle \cos\alpha= -\frac{3}{5}

$\displaystyle \cos\alpha= \frac{3}{5}$\displaystyle \cos\alpha= \frac{3}{5}