Show that the direction cosines of a vector equally inclined to the axes \( \mathrm{OX}, \mathrm...

Show that the direction cosines of a vector equally inclined to the axes \( \mathrm{OX}, \mathrm{OY} \) and \( \mathrm{OZ} \) are \( \frac{1}{\sqrt{3}}, \frac{1}{\sqrt{3}}, \frac{1}{\sqrt{3}} \).