If the pair of straight lines ax2+2hxy−ay2=0 and bx2+2gxy−by2=0 be such that each bisect the angle between the other, then
If the bisector of the angles between the pairs of lines given by the equation ax2+2hxy+by2=0 and ax2+2hxy+by2+λ(x2+y2)=0 be coincident, then λ =