If `theta` is the angle between two lines whose d.c's are `(l_(1),m_(1),n_(1))` and `(l_(2),m_(2),n_(2))` then the lines are perpendicular if and only if

The direction cosines of the lines bisecting the angle between the lines whose direction cosines are l_(1),m_(1),n_(1) and l_(2),m_(2),n_(2) and the angle between these lines is theta, are

Two lines with direction cosines l_(1),m_(1),n_(1) and l_(2), m_(2), n_(2) are at right angle of

The direction cosines of the lines bisecting the angle between the lines whose direction cosines are I_(1),m_(1),n_(1) and I_(2),m_(2),n_(2) and the angle between these lines is theta ,are

The acute angle between the two lines whose d.cs are given by l+m-n=0 and l^(2)+m^(2)-n^(2)=0 is

If the direction cosines of two lines are l_(1), m_(1), n_(1) and l_(2), m_(2), n_(2) , then find the direction cosine of a line perpendicular to these lines.

The direction Cosines of two lines at right angles are l_(1),m_(1),n_(1)and l_(2),m_(2),n_(2) Then the direction cosines of a line which is perpendicular to both these lines are

The direction cosines of the lines bisecting the angle between the line whose direction cosines are l_1, m_1, n_1 and l_2, m_2, n_2 and the angle between these lines is theta , are

Find the angle between the line whose direction cosines are given by l+m+n=0 and 2l^(2)+2m^(2)-n^(2)-0

The angle between the lines whose does are given by the equation l^(2)+m^(2)-n^(2)=0,l+m+n=0 is