IF vector a ,vector b ,vector c and vector d are unit vectors such that
(vector a cross vector b) dot (vector c cross vector d )=1 and
vector a dot vector c =1/2 then
IF vector a ,vector b ,vector c and vector d are unit vectors such that
(vector a cross vector b) dot (vector c cross vector d )=1 and
vector a dot vector c =1/2 then