For the combined equation (of the pair of straight lines) H = 0, the equations of bisectors of angles is
h(x2 – y2) = (a – b)xy
(i) A pair of lines L1 L2 = 0 is said to be equally inclined to a line L = 0
if the lines L1 = 0, L2 = 0 subtend the same angle with the line L = 0. Refer adjacent fig. (i)
(ii) Every pair of lines is equally inclined to either of its angle bisectors.
(iii) A pair of lines is equally inclined to a line L = 0
iff L = 0 is parallel to one of the angle bisectors.
(iv) Two pairs of lines L1L2 = 0 and L3L4 = 0 are said to be
equally inclined to each other if the angle between the lines L1 = 0 and L3 = 0 is
equal to the angle between the lines L2 = 0 and L4 = 0. Refer adjacent fig. (ii)
(v) Two pairs of concurrent lines are equally inclined to each other
iff both the pairs of lines have the same angle bisectors.