Funkcje Cyklometryczne arcsin(cosPI/5) = ?

[latex]frac{pi}{2}-frac{3pi}{10}=frac{pi}{5}\cos(frac{pi}{2}-frac{3pi}{10})=sin(frac{3pi}{10})\ arcsin(sin(frac{3pi}{10}))=frac{3pi}{10}=54^circ[/latex]