Manipal MET2010MathematicsHyperbola
If the equation l x^2+2 m x y+n y^2=0 represents a pair conjugate diameter of the hyperbola x^2 a^2 - y^2 b^2 =1 , then
Options
- Al a^2+n b^2=0
- Bl a^2=n b^2
- C2 l a^2=n b^2
- DNone of these
Correct answer
B. l a^2=n b^2
Step-by-step solution
Let y=m₁ x and y=m₂ x be the lines represented by l x^2+2 m x y+n y^2=0 , then m₁ m₂= l n ...(i) But y=m₁ x and y=m₂ x are conjugate diameters of the hyperbola. m₁ m₂= b^2 a^2 ...(ii) From Eqs. (i) and (ii), we get l n = b^2 a^2 l a^2=n b^2