1.

If (l_(1),m_(1),n_(1)),(l_(2),m_(2),n_(2)) are direction cosines of two lines which inculude an angle 120^(@), then the direction cosines of the line which bisects the angle between them is

Answer»

`(l_(1)+l_(2)),(m_(1)+m_(2)),(n_(1)+n_(2))`
` ((l_(1)-l_(2))/(sqrt(3)),(m_(1)-m_(2))/(sqrt(3)),(n_(1)-n_(2))/(sqrt(3)))`
` ((l_(1)-l_(2))/(2),(m_(1)-m_(2))/(2),(n_(1)-n_(2))/(2))`
` ((l_(1)-l_(2))/(sqrt(2)),(m_(1)-m_(2))/(sqrt(2)),(n_(1)-n_(2))/(SQRT2))`

Answer :B


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