12. Find the shortest distance between the lines r ⃗=(i ̂+2j ̂+k ̂ )+λ(i ̂-j ̂+k ̂ ) and r ⃗=2

12. Find the shortest distance between the lines
r ⃗=(i ̂+2j ̂+k ̂ )+λ(i ̂-j ̂+k ̂ ) and
r ⃗=2i ̂-j ̂-k ̂+μ(2i ̂+j ̂+2k ̂)