Pair Of Straight Lines Question 102

Question: The equation of the bisectors of angle between the lines represented by equation $ {{(y-mx)}^{2}}={{(x+my)}^{2}} $ is

Options:

A) $ mx^{2}+(m^{2}-1)xy-my^{2}=0 $

B) $ mx^{2}-(m^{2}-1)xy-my^{2}=0 $

C) $ mx^{2}+(m^{2}-1)xy+my^{2}=0 $

D) None of these

Show Answer

Answer:

Correct Answer: A

Solution:

The equation is $ y^{2}+m^{2}x^{2}-2mxy-x^{2}-m^{2}y^{2}-2mxy=0 $

$ \Rightarrow x^{2}(m^{2}-1)+y^{2}(1-m^{2})-4mxy=0 $

Therefore, the equation of bisectors is $ \frac{x^{2}-y^{2}}{xy} $

$ =\frac{(m^{2}-1)-(1-m^{2})}{-2m} $

$ \Rightarrow mx^{2}+(m^{2}-1)xy-my^{2}=0 $ .