BITSAT 2012 Paper

If (l1,m1,n1) and (l2,m2,n2) are the direction ratios then angle between the lines is
cos θ =
Here l1 = 1, m1 = 1, n1 = 1 and
l2 = 1, m2 = – 1, n2 = n and θ = 60º
∴ cos 60° =
⇒

1

2

=

n

√3√2+n2

⇒ 3 (2 + n2) = 4n2
⇒ n2 = 6 ⇒ n = ± √6