William Elliot <email@example.com> wrote in news:Pine.NEB.firstname.lastname@example.org:
> How do we find the shortest distance between two lines L, L' in R^3
Each line has a direction vector. The cross product n of the two direction vectors is perpendicular to both lines. Pick a point on each line, P and Q. The projection of the vector from P to Q onto the vector n is the distance.