2. Questions Bank
  3. JEE Main & Advanced
  4. Mathematics
  5. Pair of Straight Lines

JEE Main & Advanced Mathematics Pair of Straight Lines Question Bank Equation of Pair of Straight Lines

  • question_answer
    The value of \[\lambda \] for which the equation \[{{x}^{2}}-\lambda xy+2{{y}^{2}}+3x-5y+2=0\] may represent a pair of straight lines is [Kurukshetra CEE 1996]

    A)            2    

    B)            3

    C)            4    

    D)            1

    Correct Answer: B

    Solution :

               \[1\times 2\times 2+2\times \left( \frac{-5}{2} \right)\times \frac{3}{2}\times \left( \frac{-\lambda }{2} \right)-1\times \frac{25}{4}-2\times \frac{9}{4}-2\frac{{{\lambda }^{2}}}{4}=0\]                    \[\Rightarrow \lambda =3,\,\frac{9}{2}\].


You need to login to perform this action.
You will be redirected in 3 sec spinner