Pair Of Straight Lines Question 127
Question: If one of the lines of the pair $ ax^{2}+2hxy+by^{2}=0 $ bisects the angle between positive directions of the axes, then a, b, h satisfy the relation
[Roorkee 1992]
Options:
A) $ a+b=2|h| $
B) $ a+b=-2h $
C) $ a-b=2|h| $
D) $ {{(a-b)}^{2}}=4h^{2} $
Show Answer
Answer:
Correct Answer: B
Solution:
Bisector of the angle between positive directions of the axes is $ y=x $ .
Since it is one of the lines of the given pair $ ax^{2}+2hxy+by^{2}=0, $ we have $ x^{2}(a+2h+b)=0 $ or $ a+b=-2h $ .