Teaching DSSSB PGT Mock Test 2025 Mathematics Three Dimensional Geometry Direction ratios and Direction cosines
Suppose L1 and L2 are two lines having the direction ratios 1, -2, -2 and 0, 2, 1 respectively. If the direction cosines of a line perpendicular to both L1 and L2 are l, m, n then |l| + |m| + |n| =
1
3
2
\(\frac{5}{3}\)
3
√3
4
\(\frac{7}{3}\)