The distance between the lines r ̅ = ( ̂i + ̂j + ̂k) + λ (3 ̂i + ̂j + 2 ̂k) and r ̅ = ( ̂2i + 2 ̂j +3 ̂k) + μ (3 ̂i + ̂j +2 ̂k) is-
Answer & explanation
Correct answer: option 1
The given lines are r ̅ = ( ̂i + ̂j + ̂k) + λ (3 ̂i + ̂j + 2 ̂k) and r ̅ = ( ̂2i + 2 ̂j +3 ̂k) + μ (3 ̂i + ̂j +2 ̂k)
The given lines are parallel
a1 ̅ =( ̂i + ̂j + ̂k), a2 ̅ = (2 ̂i + 2 ̂j +3 ̂k) and b ̅ = (3 ̂i + ̂j +2 ̂k)
Therefore the distance between the two lines is given by
d= mod{ b ̅ x (a2 ̅ - a1 ̅ )/ mod(b) }
⇒ d= mod{ (3 ̂i + ̂j +2 ̂k) x ( ̂i + ̂j +2 ̂k)/ √9+1+4 }
⇒ d= mod{ ( 0 ̂i + 4 ̂j +2 ̂k)/ √14 }
⇒ d= (√20/ √14 )