Matematika A - 2023. ljeto, 17.

\( \cos \varphi = \frac{x^{2}+y^{2}-z^{2}}{2 x y} \)

\( \cos \varphi=\frac{x^{2}+y^{2}-z^{2}}{2 y z} \)

\( \cos \varphi=\frac{x^{2}+z^{2}-y^{2}}{2 x y} \)

\( \cos \varphi=\frac{y^{2}+z^{2}-x^{2}}{2 y z} \)