JEE Main & Advanced Mathematics Pair of Straight Lines Question Bank Angle between the pair of straight lines, Condition for parallel and perpendicular lines

  • question_answer
    Pair of straight lines perpendicular to each other represented by                                                              [Roorkee 1990]

    A)            \[2{{x}^{2}}=2y(2x+y)\]   

    B)            \[{{x}^{2}}+{{y}^{2}}+3=0\]

    C)            \[2{{x}^{2}}=y(2x+y)\]     

    D)            \[{{x}^{2}}=2(x-y)\]

    Correct Answer: A

    Solution :

               Since\[2{{x}^{2}}=2y(2x+y)\Rightarrow {{x}^{2}}-2xy-{{y}^{2}}=0\].            Hence, coefficient of \[{{x}^{2}}+\]coefficient of \[{{y}^{2}}=1-1=0\].            Hence the lines are perpendicular.


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