Quaternions can be defined from the axis angle of rotation by
Testing some escape charachters for html category with a generator has an injective cogenerator" now escape ” with "
![$\displaystyle \left[ \begin{array}{c} q_1 \ q_2 \ q_3 \ q_4 \end{array} \... ...( \alpha /2 ) \ e_3 sin( \alpha /2 ) \ cos( \alpha /2 ) \end{array} \right]$](http://images.physicslibrary.org/cache/objects/90/l2h/img1.png "$\displaystyle \left[ \begin{array}{c} q_1 \ q_2 \ q_3 \ q_4 \end{array} \... ...( \alpha /2 ) \ e_3 sin( \alpha /2 ) \ cos( \alpha /2 ) \end{array} \right]$")