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

Options

A. `(l_(1)+l_(2))/(2 sin theta//2),(m_(1)+m_(2))/(2 sin theta//2),(n_(1)+n_(2))/(2 sin theta//2)`
B. `(l_(1)+l_(2))/(2 cos theta//2),(m_(1)+m_(2))/(2 cos theta//2),(n_(1)+n_(2))/(2 cos theta//2)`
C. `(l_(1)-l_(2))/(2 sin theta//2),(m_(1)-m_(2))/(2 sin theta//2),(n_(1)-n_(2))/(2 sin theta//2)`
D. `(l_(1)-l_(2))/(2 cos theta//2),(m_(1)-m_(2))/(2 cos theta//2),(n_(1)-n_(2))/(2 cos theta//2)`

Answer

B

Explanation

NA