If `l_(1), m_(1), n_(1)` and `l_(2), m_(2), n_(2)` are the direction cosines of two lines and `l`, m, n are the direction cosines of a line perpendicular to the given two lines, then

If (1,2,1), (1,-3,2) are the direction ratios of two lines and (l, m,n) are the direction cosines of a line perpendicular to the given lines, then l + m + n

If (l_(1),m_(1),n_(1)) and (l_(2),m_(2),n_(2)) are the direction cosines of two lines find the direction cosines of the line which is perpendicular to both these lines.

If l_(1), m_(1), n_(1) and l_(2),m_(2),n_(2) are the direction cosines of two mutually perpendicular lines, show that the direction cosines of the line perpendicular to both of these are m_(1)n_(2)-m_(2)n_(1),n_(1)l_(2)-n_(2)l_(1),l_(1)m_(2)-l_(2)m_(1) .

If l_(1), m_(1), n_(1) and l_(2),m_(2),n_(2) are the direction cosines of two mutually perpendicular lines, show that the direction cosines of the line perpendicular to both of these are m_(1)n_(2)-m_(2)n_(1),n_(1)l_(2)-n_(2)l_(1),l_(1)m_(2)-l_(2)m_(1) .

If l_(1), m_(1), n_(1) and l_(2),m_(2),n_(2) are the direction cosines of two mutually perpendicular lines, show that the direction cosines of the line perpendicular to both of these are m_(1)n_(2)-m_(2)n_(1),n_(1)l_(2)-n_(2)l_(1),l_(1)m_(2)-l_(2)m_(1) .

If l_(1), m_(1), n_(1) and l_(2), m_(2), n_(2) are the direction cosines of two mutually perpendicular lines show that the Direction Cosines of the line perpendicular to both of them are m_(1)n_(2) - n_(1)m_(2), n_(1)l_(2) - l_(1)n_(2), l_(1)m_(2) - m_(1)l_(2)