defence exam Coast Guard Navik GD (General Duty) 02/2025 Mock Test Series Mathematics Vector Algebra Magnitude and Directions of a Vector
If l1, m1, n1 and l2, m2, n2 are the direction cosines of two concurrent lines, then the direction cosines of the lines bisecting the angles between them are proportional to :
1
\(\pm \frac{l_{1}}{l_{2}}, \pm \frac{m_{1}}{m_{2}}, \pm \frac{n_{1}}{n_{2}} \)
2
\(\pm \sqrt{l_{1} l_{2}}, \pm \sqrt{m_{1} m_{2}}, \pm \sqrt{n_{1} n_{2}} \)
3
l1 ± l2, m1 ± m2, n1 ± n2
4
\(\pm \sqrt{\frac{l_{1}}{l_{2}}}, \pm \sqrt{\frac{m_{1}}{m_{2}}}, \pm \sqrt{\frac{n_{1}}{n_{2}}} \)