Find the shortest distance between the following pairs of nonparallel lines and find the points on the lines that are closest together.
(a) [x y z]T = [1 -1 0]T + s[1 1 1]T
[x y z]T = [2 -1 3]T + t[3 1 0]T
(b) [x y z]T = [1 2 3]T + s[2 0 -1]T
[x y z]T = [3 -1 0]T + t[1 1 0]T