TeX джерело:
\cos\alpha=\frac{a_{ {x}}b_{ {x}}+a_{ {y}}b_{{y}}+a_{ {z}}b_{ {z}}}{\sqrt{a_{ {x}}^{ e {2}}+a_{ {y}}^{{2}}+a_{ {z}}^{ {2}}}\,\sqrt{b_{ {x}}^{ {2}}+b_{ {y}}^{ {2}}+b_{ {z}}^{ {2}}}}.